Hidden high rate of pre-eclampsia in twin compared with singleton pregnancy

The prognostic nutritional index is associated with preeclampsia in twin pregnancies

OBJECTIVE

We aimed to investigate the relationship between the prognostic nutritional index (PNI) during the third trimester and the risk of preeclampsia (PE) in twin pregnancies.

METHOD

A total of 2998 twin pregnancies were enrolled in Fujian Maternal and Child Health Hospital from January 2015 to December 2021, including preeclampsia group (n = 421) and control group (n = 2577). The significance of the characteristic variables in predicting PE in twin pregnancies were calculated using the random forest algorithm (Boruta package) and the correlation between PNI and PE in twin pregnancies was examined in three distinct models using multivariable logistic regression corrected for confounders. Receiver operating characteristics (ROC) curves were used to evaluate the ability for PNI to predict PE in twin pregnancies.

RESULTS

PNI (37.92 ± 3.86 vs. 40.57 ± 3.63, P < 0.001) was significantly lower in the PE group than in the control group. After adjusting for all covariates, the PNI was negatively associated with PE in twin pregnancies (OR = 0.780; 95% CI: 0.753, 0.808). Meanwhile, the higher PNI remained an independent protective factor for PE in twin pregnancies compared to lower PNI (OR, 95% CI: 0.410, 0.438-0.530; 0.144, 0.103-0.201) in sensitivity analysis. ROC curve analysis revealed an area under curve (AUC) of 0.691 for PNI and the cut-off value of PNI was 40.162.

CONCLUSION

PNI was negatively correlated with the risk of PE in twin pregnancies, which may help in risk assessment for twin pregnancies.

CLINICAL TRIAL NUMBER

Not applicable.

Early prediction of preeclampsia from clinical, multi-omics and laboratory data using random forest model

BACKGROUND

Predicting preeclampsia (PE) within the first 16 weeks of gestation is difficult due to various risk factors, poorly understood causes and likely multiple pathogenic phenotypes of preeclampsia.  OBJECTIVES: In this study, we aimed to develop prediction models for early-onset preeclampsia (EPE) and late-onset preeclampsia (LPE) respectively using clinical data, metabolome and proteome analyses on plasma samples and laboratory data.

METHODS

We retrospectively recruited 56 EPE, 50 LPE patients and 92 normotensive controls from three tertiary hospitals and used clinical and laboratory data in early pregnancy. Models for EPE and LPE were fitted with the use of patient' clinical, multi-omics and laboratory data.

RESULTS

By comparing multi-omics and laboratory test variables between EPE, LPE and healthy controls, we identified sets of differentially expressed biomarkers, including 49 and 33 metabolites, 28 and 36 proteins as well as 5 and 7 laboratory variables associated with EPE and LPE respectively. Using the random forest algorithm, we developed a prediction model using seven clinical factors, seven metabolites, five laboratory test variables. The model yielded the highest accuracy for EPE prediction with good sensitivity (87.5%, 95% confidence interval [CI]: 67.64%-97.34%) and specificity (94.1%, 95% CI: 80.32%-99.28%). We also developed a prediction model that exhibited high accuracy in separating LPE from controls (sensitivity: 66.67%, 95% CI: 43.03%-85.41%; specificity: 94.12%, 95% CI: 80.32%-99.28%) using seven clinical factors, five metabolites and eight proteins.

CONCLUSION

Our study has identified a set of significant omics and laboratory features for PE prediction. The established models yielded high prediction performance for preeclampsia risk from clinical, multi-omics and laboratory information.

Prediction of hypertension and diabetes in twin pregnancy using machine learning model based on characteristics at first prenatal visit: national registry study

OBJECTIVE

To develop a prediction model for hypertensive disorders of pregnancy (HDP) and gestational diabetes mellitus (GDM) in twin pregnancy using characteristics obtained at the first prenatal visit.

METHODS

This was a cross-sectional study using national live-birth data in the USA between 2016 and 2021. The association of all prenatal candidate variables with HDP and GDM was tested on univariable and multivariable logistic regression analyses. Prediction models were built with generalized linear models using the logit link function and classification and regression tree (XGboost) machine learning algorithm. Performance was assessed with repeated 2-fold cross-validation and the area under the receiver-operating-characteristics curve (AUC) was calculated. A P value < 0.001 was considered statistically significant.

RESULTS

A total of 707 198 twin pregnancies were included in the HDP analysis and 723 882 twin pregnancies were included in the GDM analysis. The incidence of HDP and GDM increased significantly from 12.6% and 8.1%, respectively, in 2016 to 16.0% and 10.7%, respectively, in 2021. Factors associated with increased odds of HDP in twin pregnancy were maternal age < 20 years or ≥ 35 years, infertility treatment, prepregnancy diabetes mellitus, non-Hispanic Black race, overweight prepregnancy BMI, prepregnancy obesity and Medicaid as the payment source for delivery (P < 0.001 for all). Obesity Class II and III more than doubled the odds of HDP. Factors associated with increased odds of GDM in twin pregnancy were maternal age ≤ 24 years or ≥ 30 years, infertility treatment, prepregnancy hypertension, non-Hispanic Asian race, maternal birthplace outside the USA and prepregnancy obesity (P < 0.001 for all). Maternal age ≥ 30 years, non-Hispanic Asian race and obesity Class I, II and III more than doubled the odds of GDM. For both HDP and GDM, the performances of the machine learning model and logistic regression model were mostly similar, with negligible differences in the performance domains tested. The mean ± SD AUCs of the final machine learning models for HDP and GDM were 0.620 ± 0.001 and 0.671 ± 0.001, respectively.

CONCLUSIONS

The incidence of HDP and GDM in twin pregnancies in the USA is increasing. The predictive accuracy of the machine learning models for HDP and GDM in twin pregnancies was similar to that of the logistic regression models. The models for HDP and GDM had modest predictive performance, were well calibrated and did not have poor fit. © 2024 The Author(s). Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

Comparative study on the factors influencing pre-eclampsia symptoms at different pregnancy stages in Bangladeshi women: urban vs. rural perspectives

BACKGROUND

In Bangladesh, pre-eclampsia poses a significant concern, evident in the low attendance (37%) for antenatal care (ANC). Despite efforts to reduce maternal and neonatal mortality, the latest Bangladesh Maternal Mortality Survey (BMMS-2016) indicates limited progress. Access to essential maternal and newborn health services, including ANC, remains constrained, highlighting the challenge of translating service coverage into improved outcomes. A research gap on pre-eclampsia symptoms such as severe headache, blurred vision, high blood pressure, and oedema emphasizes the need for targeted interventions for these symptoms early so that we can reduce the prevalence of pre-eclampsia and therefore maternal mortality in Bangladesh. The aim of this study is to investigate and compare the risk factors for three stages of pre-eclampsia among Bangladeshi women living in urban and rural areas.

METHODS

The study utilized BMMS-2016 data, employing statistical analyses, including binary logistic regression, to identify associations. It assessed four pre-eclampsia symptoms prevalence across pregnancy stages, considering factors like maternal age, stillborn births, residency, ANC, healthcare facility delivery, education, and children.

RESULTS

Logistic regression highlights key associations with pre-eclampsia symptoms. Urban mothers aged 36 + face the highest risk during delivery (AOR = 2) and the lowest in rural areas after delivery (AOR = 1.43). Two or more stillborn births increase the risk in urban delivery by 97%. Complete ANC raises odds, notably in urban pregnancy (AOR = 1.5) and rural post-delivery (AOR = 1.16). Skilled ANC providers elevate risks during all stages, with the highest in urban pregnancy (AOR = 1.54) and lowest after rural delivery (AOR = 1.28). Unskilled ANC associates with symptoms only during pregnancy. Healthcare facility delivery increases odds at all stages, particularly in rural delivery (AOR = 1.74) and urban pregnancy (AOR = 1.26). Multifetal gestation raises urban delivery risk (AOR = 2.11). Rural areas show higher chances during both pregnancy and delivery. Higher education in rural pregnancy and 2 to 3 birth order in urban delivery reduce odds of pre-eclampsia symptoms.

CONCLUSIONS

Addressing pre-eclampsia symptoms in Bangladesh, especially among urban women, is urgent. Identified risk factors necessitate targeted interventions to enhance ANC and overall maternal health. Advocating findings to policymakers is crucial for effective policies, reducing pre-eclampsia and eclampsia, contributing to lower maternal mortality.

Hospitalization for cardiovascular disease in the year after delivery of twin pregnancies

BACKGROUND AND AIMS

Increased cardiovascular demand in twin pregnancies, even those without hypertensive disease of pregnancy (HDP), may pose a greater risk for cardiovascular complications compared with singletons. In this study, the risk of cardiovascular disease (CVD)-related hospitalizations and mortality within the year following delivery in relation to HDP was compared between twin and singleton pregnancies.

METHODS

Using the Nationwide Readmissions Database of US hospitals from 2010 to 2020, the rates of CVD readmission in four exposure groups (twin deliveries with and without HDP and singleton deliveries with and without HDP) were estimated. Cox proportional hazard regression models were used to determine associations with singletons without HDP as the reference.

RESULTS

Of 36 million delivery hospitalizations, the rates of CVD readmission in twin and singleton pregnancies were 1105.4 and 734.1 per 100 000 delivery admissions, respectively. Compared with singletons without HDP, the adjusted hazard ratio (HR) of CVD readmission was highest for twins with HDP [HR 8.21, 95% confidence interval (CI) 7.48-9.01], followed by singletons with HDP (HR 5.89, 95% CI 5.70-6.08) and then twins without HDP (HR 1.95, 95% CI 1.75, 2.17).

CONCLUSIONS

Compared with singletons without HDP, twin pregnancies, even in the absence of HDP, are associated with increased risks for CVD complications in the first year post-partum. These findings highlight the increased strain twin pregnancies place on the maternal cardiovascular system. These findings advocate the need for appropriate pre-conception counselling for those with cardiovascular risk factors undergoing infertility treatment, which increase the risks of multi-foetal gestation, and increased post-partum surveillance in twin pregnancies.

Twin delivery: does induction of labor make a difference?

PURPOSE

Induction of labor as well as delivery in twin pregnancies bears specific risks. The goal of this study was to analyze the delivery mode in twin pregnancies and influence of induction on the cesarean delivery (CD) rate and perinatal outcome and to identify risk factors for CD and an intertwin interval ≥ 15 min.

METHODS

This single-center retrospective cohort study analyzed the outcome of 267 twin pregnancies. Inclusion criteria for vaginal delivery in twins are gestational age (GA) > 34 weeks, leading twin in cephalic presentation, estimated weight difference ≤ 500 g and no previous uterine surgery. Women were divided into three groups: 1 = vaginal delivery, 2 = CD for both twins, 3 = emergency CD for second twin. Outcomes were mode of delivery, and influence of induction on the CD rate.

RESULTS

We had 156 women (58%) in group 1, 97 (36%) in 2 and 14 (5%) in 3. Induction of labor was performed in 147 cases and led to a higher CD rate (23% vs. 47%, p < 0.001). Induction of labor and nulliparity were associated with a higher risk for CD for both twins. Risk factors for an intertwin interval of ≥ 15 min were maternal age and weight of the second twin. An intertwin interval of ≥ 15 min was associated with a lower umbilical artery pH in the second twin.

CONCLUSION

The rate of CD doubled if induction of labor was necessary. These results emphasize on careful patient counseling that includes information about the risks of deliveries in twin pregnancies.

Association between twin status with cognitive, behavioral development and brain structure in early adolescence: a retrospective cohort analysis based on the Adolescent Brain Cognitive Development Study

Twin births are related with maternal and fetal adverse outcomes. Little was known about the comparability of the cognitive, behavioral development and brain structure between twins and singletons in early adolescence. This retrospective cohort study was based on data from the United States population-based, prospective, longitudinal observational Adolescent Brain Cognitive Development study. Children with complete twin status information were enrolled, and the exposure variable was twin status. Primary outcomes were cognitive, behavioral development and brain structure in early adolescence. Cognitive and behavioral outcomes were assessed by using the NIH Toolbox and Child Behavioral Checklist, respectively. Brain structure was evaluated by the cortical thickness, area, and volume extracted from the magnetic resonance imaging (MRI) data. Subgroup analyses were conducted by prematurity, birth weight, with sibling, genetic profiles, and twin types (zygosity). From 1st September 2016 to 15th November 2018, 11545 children (9477 singletons and 2068 twins) aged 9-10 years were enrolled. Twins showed mildly lower cognitive performance (|t|> 5.104, P-values < 0.001, False Discovery Rate [FDR] < 0.001), better behavioral outcome (|t|> 2.441, P-values < 0.015, FDR < 0.042), such as lower scores for multiple psychiatric disorders and behavioral issues, and smaller cortical volume (t = - 3.854, P-values < 0.001, FDR < 0.001) and cortical area (t = - 3.872, P-values < 0.001, FDR < 0.001). The observed differences still held when stratified for prematurity, birth weight, presence of siblings, genetic profiles, and twin types (zygosity). Furthermore, analyses on the two-year follow-up data showed consistent results with baseline data. Twin status is associated with lower cognitive and better behavioral development in early adolescence accompanied by altered brain structure. Clinicians should be aware of the possible difference when generalizing results from adolescent twin samples to singletons.

An Unusual and Severe Thyrotoxicosis in a Twin Pregnancy: Fortune Favors the Brave

Graves' disease (GD) and gestational transient thyrotoxicosis (GTT) are the most common causes of thyrotoxicosis during pregnancy, with prevalence ranging from 0.1% to 1% and from 1% to 3%, respectively. Hyperthyroidism during pregnancy can have severe consequences if not promptly recognized and treated. Even more severe, if possible, is the thyroid storm, a life-threatening complication of hyperthyroidism, characterized by severe and dramatic clinical manifestations of thyrotoxicosis. No prior history of thyroid disease, absence of GD stigmata, negative thyrotropin (TSH) receptor antibody levels, serum human chorionic gonadotropin (hCG) higher on average, and symptoms of emesis may lead to the diagnosis of GTT. Few cases of thyroid storm during pregnancy are reported in literature, mainly due to gestational trophoblastic disease. We report a rare and severe case of thyroid storm in a 24-year-old woman at 15 weeks' gestation with twins, likely due to GTT, precipitated by acute myocarditis. Initially presenting with weakness, vomiting, and sinus tachycardia, the patient rapidly deteriorated into a life-threatening condition characterized by hypokalemia, myocardial injury, and severe thyrotoxicosis. Cardiac imaging later revealed acute myocarditis. Thyroid function stabilized at the end of the pregnancy, allowing discontinuation of methimazole. Both fetuses were delivered via emergency cesarean section at 36 weeks, with no significant congenital abnormalities. This case highlights the complexity of diagnosing and managing hyperthyroidism in twin pregnancies, particularly in the context of hyperemesis gravidarum (HG).

Comparison of two aspirin doses for the prophylaxis of pre-eclampsia in twin pregnancy: a multicentre retrospective study with propensity score matching

BACKGROUND

Aspirin has proved its efficacy in reducing the rate of preeclampsia in singleton pregnancy; however, there is discrepancy about the efficient dosage that should be used. While some societies recommend daily 75 to 81 mg, others recommend higher dosage (160 mg). This discrepancy is due to the lack of randomized controlled studies that compare these 2 dosages. Moreover, there remains a considerable gap in our knowledge concerning the appropriate prophylactic aspirin dosage for twin pregnancies.

OBJECTIVE

This study aimed to assess the efficacy of various aspirin prophylaxis dosages in the prevention of preeclampsia and hypertensive disorders of pregnancy (HDP) in twin pregnancies.

STUDY DESIGN

This was an international multicentre retrospective cohort study that was conducted in 3 European centers. We included all twin pregnancies with 2 live fetuses at 13 weeks of gestation (WG). We excluded fetal malformations, twin-twin transfusion syndrome, twin anemia polycythemia sequence, twin reversed arterial perfusion sequence, twin pregnancies at onset but continued as singletons (vanishing twin/arrest before 13 WG), and loss of follow-up. Patients were categorized into 3 groups: no aspirin, daily 80 to 100 mg aspirin, and daily 160 mg aspirin. Primary outcomes were the incidence of preeclampsia and HDP, whereas secondary outcomes were small-for-gestational age, postpartum hemorrhage >1000 mL, antenatal bleeding of obstetrical origin, thrombocytopenia, miscarriage, intrauterine fetal demise, neonatal death, and gastritis. Propensity score matching and multivariate analyses were conducted to assess outcomes including pre-eclampsia, gestational hypertension, maternal complications, and gastritis. Propensity score matching was used to balance the 3 groups of study. Cox regression models were done for each outcome after matching to compare the 3 groups. A P-value<.05 was considered statistically significant.

RESULTS

A total of 1907 twin pregnancies were included: 1423 (74.62%) received no aspirin, 212 (11.12%) received 80 to 100 mg, and 272 (14.26%) received 160 mg. After using propensity score matching for maternal age, body mass index, race, parity, history of preeclampsia, chronic hypertension, diabetes mellitus, thrombophilia, spontaneous conception, and type of twin pregnancy, the 3 groups were adequately balanced (absolute standardized difference [ASD] <15%), except for age and thrombophilia (ASD 22.1% and 16.4%, respectively). The administration of aspirin 160 mg decreased the hazard ratio (HR) for preeclampsia to 0.63 and for HDP to 0.56, whereas the administration of aspirin 80 to 100 mg failed to decrease both HR below 1. In addition, aspirin 160 mg decreased the risk for preeclampsia <34 WG. No significant increase for aspirin-related complications, such as bleeding or thrombocytopenia, or other obstetrical outcomes was observed with the higher dose of aspirin.

CONCLUSION

The use of 160 mg aspirin for the prevention of hypertensive disorders of pregnancy may offer superior outcomes in twin pregnancies, with no discernible rise in complications when compared to aspirin doses ranging from 80 to 100 mg. Further research should explore long-term impacts and refine dosage strategies for optimal outcomes in twin pregnancies.

Predictive value of urine misfolded protein in preeclampsia in twin pregnancies

OBJECTIVE

To assess the utility of urinary misfolded proteins (MP) in predicting preeclampsia (PE) in high-risk twin pregnancies.

METHODS

A prospective study was conducted on 600 high-risk twin pregnancies at Shanghai First Maternity and Infant Hospital from March to August 2021. Clinical data were collected, and urinary MP levels were measured. Subsequently, fetal outcomes were monitored. The patients were categorized into three groups based on the presence of PE: unaffected PE group, early-onset PE (ePE) group (gestational age < 34 weeks), and late-onset PE (lPE) group (gestational age ≥ 34 weeks). The predictive value of MP in PE was evaluated using analysis of variance, Chi-square test, and ROC curve analysis.

RESULTS

A total of 464 twin pregnancies were included in the study, among which 66 cases (14.2%) developed PE, including 19 cases of ePE (4.1%) and 47 cases (10.1%) of lPE. Significant differences were found in maternal age, pre-pregnancy body mass index (BMI), BMI ≥ 28 km/m2, mean systolic blood pressure, diastolic blood pressure, mean arterial pressure (MAP), MAP ≥ 85 mmHg, history of PE, history of chronic hypertension, and positive urine protein. The maternal and fetal complications of twin pregnancies with PE were higher than those without PE (P < 0.05). When maternal factors (MF), MAP, and MP were used to predict ePE and lPE alone, the area under the ROC curve of MF was the largest, at 0.739 (95% CI 0.619-0.860) and 0.692 (95% CI 0.603-0.782), respectively. The area under the ROC curve of the combination of the three factors was 0.770 (95% CI 0.703-0.837), higher than that of a single index. In addition, MP predicted the positive predictive value (PPV) and negative predictive value (NPV) of PE from 12 to 15+6 gestational weeks as 57.9% and 89.2%, respectively; from 16 to 27+6 gestational weeks as 36.2% and 89.9%, respectively; and during the 12-27+6 gestational weeks as 42.4% and 92.2%, respectively.

CONCLUSION

The detection of MP in the urine of women with twin pregnancies is a non-invasive and convenient method for predicting PE. If the test result is positive, enhanced monitoring and timely transfer to a superior hospital are necessary. If the test result is negative, it indicates a low risk of developing PE, reducing the need for excessive clinical examination and intervention.

First-trimester uterine artery Doppler and hypertensive disorders in twin pregnancies: Use of twin versus singleton references

OBJECTIVE

To determine the association of first-trimester uterine artery Doppler with hypertensive disorders of pregnancy in twin pregnancies.

METHODS

This was a retrospective cohort study of twin pregnancies followed at the University Hospital Center of Central Lisbon, Portugal, between January 2010 and December 2022. First-trimester uterine artery pulsatility index (UtA-PI) was determined and compared between twin pregnancies (n = 454) and singleton pregnancies (n = 908), matched to maternal and pregnancy characteristics. Maternal characteristics and mean UtA-PI were analyzed for gestational age, birth weight, gestational hypertension, early- and late-onset pre-eclampsia, HELLP (hemolysis, elevated liver enzymes, low platelets) syndrome, and preterm birth. Univariable and multivariable logistic regression models were used.

RESULTS

The mean first-trimester UtA-PI was significantly lower in dichorionic twins than in singletons (P < 0.001). To study hypertensive disorders of pregnancy in twins, 390 pregnancies were included: 311 (79.7%) dichorionic and 79 (20.3%) monochorionic twins. The observed rates of early- and late-onset pre-eclampsia, gestational hypertension, and HELLP syndrome were 1.0%, 4.4%, 7.4%, and 1.5%, respectively. We achieved a 100% detection rate for early-onset pre-eclampsia using the UtA-PI 90th centile for twins. However, when singleton references were considered, the detection rate decreased to 50%. UtA-PI at or above the 95th centile was associated with increased odds for preterm birth before 32 weeks (adjusted odds ratio 4.1, 95% confidence interval 1.0-16.7, P = 0.043).

CONCLUSIONS

Unless other major risk factors for hypertensive disorders are present, women with low UtA-PI will probably not benefit from aspirin prophylaxis. Close monitoring of all twin pregnancies for hypertensive disorders is still recommended.

The impact of maternal serum biomarkers on maternal and neonatal outcomes in twin pregnancies: a retrospective cohort study conducted at a tertiary hospital

Background

Prior prediction models used for screening preeclampsia (PE) in twin pregnancies were found to be inadequate. In singleton pregnancies, various maternal biomarkers have been shown to be correlated with negative pregnancy outcomes. However, the impact of these biomarkers in twin pregnancies remained uncertain.

Methods

A retrospective cohort study was carried out on 736 twin pregnancies at a tertiary hospital in Hangzhou, China. Multivariable logistic models were employed to examine the association between levels of serological markers and the likelihood of adverse pregnancy outcomes. The final logistic model was formulated as a user-friendly nomogram. The primary outcome assessed was the occurrence of PE. Results were presented as odds ratios (ORs) with corresponding 95% confidence intervals (CIs).

Results

The prevalence of PE in the study was 10.3%. When comparing women diagnosed with PE to those without, it was evident that the former group experienced a significantly higher risk of unfavorable maternal and neonatal outcomes. A multivariable logistic regression analysis revealed notable associations between various factors including maternal age, parity, gestational weight gain, a family history of hypertension, as well as levels of cholesterol, albumin, and creatinine and the risk of developing PE, with a significance level of P < 0.05. The concordance index for the constructed nomogram was determined to be 0.792 (95% CI: [0.739-0.844]). Furthermore, an increment of 1 * 1012/L in red blood cell (RBC) count was associated with more than a two-fold increase in the odds of experiencing adverse maternal outcomes (OR 2.247, 95% CI: [1.229-4.107]). However, no significant correlations were identified between any of the examined variables and neonatal outcomes.

Conclusions

In this study, we developed a user-friendly predictive model that achieves notable detection rates by incorporating maternal serum biomarker levels alongside maternal characteristics and medical history. Our findings indicate that the probability of adverse maternal outcomes increases with elevated levels of RBCs. Obstetricians should consider intensifying surveillance for these women in clinical practice.

The Role of Chorionicity in Placenta-Related Disorders

INTRODUCTION

Twin pregnancy is associated with higher rates of maternal morbidities including gestational diabetes and hypertension. Dichorionic twins are believed to have greater placental mass. Our objective was to study the incidence of two placenta-related disorders: gestational diabetes and hypertension, in dichorionic versus monochorionic twin pregnancies.

METHODS

Patients' data of all consecutive twin pregnancies over a period of 12 years were collected from medical records. Data on chorionicity were retrieved from 1st trimester ultrasound reports. Maternal complications including gestational hypertension and diabetes were collected, and incidence was compared between dichorionic and monochorionic twin pregnancies. Records lacking chorionicity data and cases with pregestational diabetes were excluded.

RESULTS

A total of 960 twin pregnancies, 121 monochorionic and 839 dichorionic, were included. Average maternal age did not differ significantly between the groups. The median gestational age at delivery was 36.0 weeks in monochorionic and 36.7 in dichorionic twins. Primiparity (40.4% vs. 23.1%, p < 0.001) and the rate of infertility treatments (51.5% vs. 7.4%, p < 0.001) were both more common in the dichorionic group. The incidence of gestational hypertension disorders was 14% in monochorionic versus 11% in dichorionic twins (p = 0.36). Gestational diabetes was more common in dichorionic compared to monochorionic twins (9.4% and 2.5%, respectively); however, logistic multivariate analysis showed that gestational diabetes was highly correlated with maternal age (p < 0.001) and infertility treatments (p < 0.001) but not with chorionicity (p = 0.136).

CONCLUSION

Our results may imply that greater placental mass does not increase the risk for gestational hypertension and diabetes. This might support the role of additional multiple maternal factors associated with these complications.

Prevention of preeclampsia

Preeclampsia is a relatively common pregnancy complication and constitutes a major cause of morbidity and mortality for mothers and children worldwide. It disproportionally affects low-resource countries. Appropriate identification of individuals at increased risk and prevention of the disease and its complications remain healthcare and research priorities, and the investigation of potential interventions to prevent preeclampsia has driven much of the obstetric research in recent decades. In this article, we review the scientific literature on the topic, highlighting established benefits and remaining questions regarding different non-pharmacological and pharmacological strategies, including exercise, the timing of birth, aspirin and calcium use, among others, as well as potential novel therapies under investigation.

Incidence of neonatal morbidity in small-for-gestational-age twins based on singleton and twin charts

OBJECTIVE

To compare morbidity, as measured by length of stay in the neonatal intensive care unit (NICU), in twin and singleton gestations classified as small-for-gestational age (SGA) according to estimated fetal weight < 10th percentile on twin or singleton growth charts.

METHODS

NICU length of stay was compared in 1150 twins and 29 035 singletons that underwent ultrasound assessment between 35 + 0 and 36 + 6 weeks' gestation. Estimated fetal weight was obtained from measurements of head circumference, abdominal circumference and femur length using the Hadlock formula. Gestational age was derived from the first-trimester crown-rump length measurement, using the larger of the two twins. Singletons and twins were compared in terms of NICU admission rate and length of stay according to classification as SGA by the Fetal Medicine Foundation singleton and twin reference distributions.

RESULTS

The overall proportions of twins and singletons admitted to NICU were similar (7.3% vs 7.4%), but twins tended to have longer lengths of stay in NICU (≥ 7 days: 2.4% vs 0.8%; relative risk (RR), 3.0 (95% CI, 1.6-4.4)). Using the singleton chart, a higher proportion of twins were classified as SGA compared with singletons (37.6% vs 7.0%). However, the proportion of SGA neonates entering NICU was similar (10.2% for twins and 10.1% for singletons) and the proportion of SGA neonates spending ≥ 7 days in NICU was substantially higher for twins compared with singletons (3.7% vs 1.4%; RR, 2.6 (95% CI, 1.4-4.7)).

CONCLUSIONS

When singleton charts are used to define SGA in twins and in singletons, there is a greater degree of growth-related neonatal morbidity amongst SGA twins compared with SGA singletons. Consequently, singleton charts do not inappropriately overdiagnose fetal growth restriction in twins and they should be used for monitoring fetal growth in both twins and singletons. © 2023 International Society of Ultrasound in Obstetrics and Gynecology.

Predictive value of the soluble fms-like tyrosine kinase 1 to placental growth factor ratio for preeclampsia in twin pregnancies: a systematic review and meta-analysis

OBJECTIVE

In recent years, the ratio of soluble fms-like tyrosine kinase 1 to placental growth factor for use in predicting preeclampsia has been explored extensively. Despite extensive research, available data on its effectiveness in predicting preeclampsia in twin pregnancies are limited and conflicting. This meta-analysis aimed to assess the diagnostic accuracy of the soluble fms-like tyrosine kinase 1 to placental growth factor ratio in distinguishing cases with preeclampsia in twin pregnancies from healthy controls.

DATA SOURCES

Studies that evaluated the use of the soluble fms-like tyrosine kinase 1 to placental growth factor ratio in predicting preeclampsia were searched in PubMed, Embase, and Cochrane databases from inception to August 6, 2023, without language restriction.

STUDY ELIGIBILITY CRITERIA

The following population, exposure, comparators, outcomes, and study designs were included: women with twin pregnancies; an increased soluble fms-like tyrosine kinase 1 to placental growth factor ratio with preeclampsia as the outcome; women without preeclampsia; a 2 × 2 diagnostic table, diagnostic accuracy data, and the incidence of preeclampsia; and prospective cohort studies and observational comparative studies, respectively.

STUDY APPRAISAL AND SYNTHESIS METHODS

The quality of the included studies was evaluated. Key parameters, including the specificity, sensitivity, positive likelihood ratio, negative likelihood ratio, and diagnostic odds ratio, were calculated using the random- and fixed-effects models. In addition, the area under the receiver operating characteristic curve and the summary receiver operating characteristic curve were evaluated.

RESULTS

A total of 7 studies were included, including 442 women with twin pregnancies (115 patients with preeclampsia and 327 controls without preeclampsia). The results highlighted the promising effectiveness of the soluble fms-like tyrosine kinase 1 to placental growth factor ratio in predicting preeclampsia in twin pregnancies with a pooled specificity of 0.89 (95% confidence interval, 0.80-0.95), a sensitivity of 0.84 (95% confidence interval, 0.73-0.93), a positive likelihood ratio of 32.76 (95% confidence interval, 12.82-83.74), and a negative likelihood ratio of 0.03 (95% confidence interval, 0.01-0.08). The combined diagnostic odds ratio was 35.72 (95% confidence interval, 12.92-98.76), and the area under the receiver operating characteristic curve was 0.92.

CONCLUSION

These collective findings underscore the potential of the soluble fms-like tyrosine kinase 1 to placental growth factor ratio as an accurate marker for identifying preeclampsia among women with twin pregnancies.

Longitudinal maternal hemodynamic evaluation in uncomplicated twin pregnancies according to chorionicity: physiological cardiovascular dysfunction in monochorionic twin pregnancy

OBJECTIVE

Maternal cardiac function plays a crucial role in placental function and development. The maternal hemodynamic changes in twin pregnancy are more pronounced than those in singleton pregnancy, presumably due to a greater plasma volume expansion. In view of the correlation between maternal cardiac and placental function, it is plausible that chorionicity could influence maternal cardiac function. The aim of this study was to compare the longitudinal maternal hemodynamic changes between uncomplicated dichorionic (DC) and monochorionic (MC) twin pregnancies and in comparison to singleton pregnancies.

METHODS

Included in the study were 40 MC diamniotic and 35 DC diamniotic uncomplicated twin pregnancies. These were compared with a group of 294 healthy singleton pregnancies from a previous cross-sectional study. All participants underwent a hemodynamic evaluation using an Ultrasound Cardiac Output Monitor (USCOM®), at three different stages in pregnancy (11-15 weeks, 20-24 weeks and 29-33 weeks). The following parameters were recorded: mean arterial pressure (MAP), stroke volume (SV), stroke volume index (SVI), heart rate, cardiac output (CO), cardiac index (CI), systemic vascular resistance (SVR), systemic vascular resistance index (SVRI), stroke volume variation, Smith-Madigan inotropy index (INO) and potential-to-kinetic-energy ratio (PKR).

RESULTS

In the first trimester, DC and MC twin pregnancies showed lower MAP, SVR and PKR and higher CO and SV in comparison to singleton pregnancy. In the second trimester, maternal CO (8.33 vs 7.30 L/min, P = 0.03) and CI (4.52 vs 4.00 L/min/m2 , P = 0.02) were significantly higher in MC compared with DC twin pregnancy. In the third trimester, compared with in singleton pregnancy, women with MC twin pregnancy showed significantly higher PKR (24.06 vs 20.13, P = 0.03) and SVRI (1837.20 vs 1698.48 dynes × s/cm5 /m2 , P = 0.03), and significantly lower SV (78.80 vs 88.80 mL, P = 0.01), SVI (42.79 vs 50.31 mL/m2 , P < 0.01) and INO (1.70 vs 1.87 W/m2 , P = 0.03); these differences were not observed between DC twin and singleton pregnancies.

CONCLUSIONS

Maternal cardiovascular function undergoes significant change during uncomplicated twin pregnancy and chorionicity influences maternal hemodynamics. In both MC and DC twin pregnancy, hemodynamic changes are detectable as early as the first trimester, showing higher maternal CO and lower SVR compared with singleton pregnancy. In DC twin pregnancy, the maternal hemodynamics remain stable during the rest of pregnancy. In contrast, in MC twin pregnancy, the rise in maternal CO continues in the second trimester in order to sustain the greater placental growth. There is a subsequent crossover, with a reduction in cardiovascular performance during the third trimester. © 2023 International Society of Ultrasound in Obstetrics and Gynecology.

Fetal Medicine Foundation charts for fetal growth in twins

OBJECTIVE

To derive reference distributions of estimated fetal weight (EFW) in twins relative to singletons.

METHODS

Gestational-age- and chorionicity-specific reference distributions for singleton percentiles and EFW were fitted to data on 4391 twin pregnancies with two liveborn fetuses from four European centers, including 3323 dichorionic (DC) and 1068 monochorionic diamniotic (MCDA) twin pregnancies. Gestational age was derived using the larger of the two crown-rump length measurements obtained during the first trimester of pregnancy. EFW was obtained from ultrasound measurements of head circumference, abdominal circumference and femur length using the Hadlock formula. Singleton percentiles were obtained using the Fetal Medicine Foundation population weight charts for singleton pregnancies. Hierarchical models were fitted to singleton Z-scores with autoregressive terms for serial correlations within the same fetus and between twins from the same pregnancy. Separate models were fitted for DC and MCDA twins.

RESULTS

Fetuses from twin pregnancies tended to be smaller than singletons at the earliest gestational ages (16 weeks for MCDA and 20 weeks for DC twins). This was followed by a period of catch-up growth until around 24 weeks. After that, both DC and MCDA twins showed reduced growth. In DC twins, the EFW corresponding to the 50th percentile was at the 50th percentile of singleton pregnancies at 23 weeks, the 43rd percentile at 28 weeks, the 32nd percentile at 32 weeks and the 22nd percentile at 36 weeks. In MCDA twins, the EFW corresponding to the 50th percentile was at the 36th percentile of singleton pregnancies at 24 weeks, the 29th percentile at 28 weeks, the 19th percentile at 32 weeks and the 12th percentile at 36 weeks.

CONCLUSIONS

In DC and, to a greater extent, MCDA twin pregnancies, fetal growth is reduced compared with that observed in singleton pregnancies. Furthermore, after 24 weeks, the divergence in growth trajectories between twin and singleton pregnancies becomes more pronounced as gestational age increases. © 2023 International Society of Ultrasound in Obstetrics and Gynecology.

Potential impact on using aspirin as the primary prevention of adverse pregnancy outcomes in twins conceived using ART

With the development of assisted reproductive technology, the number of twin pregnancies is increasing year by year. Given the increased risk of pregnancy complications associated with twin pregnancies, and the fact that these babies are rare and difficult to obtain through assisted reproductive technology, clinicians urgently require finding effective and safe drugs to improve pregnancy outcomes. Low-dose aspirin can not only promote placental blood supply, but also effectively anti-inflammatory. Whether Low-dose aspirin can effectively reduce the risk of pregnancy complications in this special group needs to be clarified. We therefore retrospectively analyzed 665 twin pregnancies from assisted reproduction technology, grouped according to aspirin use, and followed pregnancy outcomes to assess bleeding risk. Low-dose aspirin was found to be effective in preventing preeclampsia without a significant risk of bleeding. However, aspirin does not prevent specific complication in twin pregnancies and seems to have a better preventive effect only when the mother is under 30, which should alarm clinicians should not blindly using aspirin in this particular group.

Exploration of Serum lipid levels during twin pregnancy

Objective: This study aims to characterize changes in serum lipid levels throughout twin pregnancies and explore the relationship between lipid levels and gestational diabetes mellitus (GDM) and hypertensive disorders complicating pregnancy (HDCP).Methods: We retrospectively studied 297 twin pregnancies of women who received regular prenatal care and delivered at the Beijing Obstetrics and Gynecology Hospital over a period of two years. Demographic and medical data of the participants were collected by questionnaires and medical records review. Serum lipid levels were measured in the first trimester (6-13 weeks), second trimester (24-28 weeks), and third trimester (34-37 weeks). A multivariate regression model was constructed to examine the association between lipid levels and pregnancy complications. A decision tree was used to explore the relationship between early serum lipid glucose levels and GDM and HDCP in twin pregnancies.Results: Triglyceride (TG), total cholesterol (TC) and low-density lipoprotein cholesterol (LDL-C) levels increased significantly from the first trimester to the third trimester, with the exception of high-density lipoprotein cholesterol (HDL-C), which decreased in the third trimester in twin pregnancies (p < 0.001). The levels of TC in the GDM and HDCP group were significantly elevated compared to those in the normal group in early pregnancies (p < 0.05, p < 0.05). In the second trimester, TG in the HDCP group was substantially higher than that in the normal group (p = 0.01). In the third trimester, LDL-C and HDL-C levels in the GDM group are significantly lower than that in the normal group (p < 0.05, p < 0.05). After adjusting for confounders, body mass index (BMI) is independently associated with GDM (odds ratio [OR] = 1.129, 95% confidence interval [CI]: 1.007-1.266) and HDCP(odds ratio [OR] = 1.170, 95% confidence interval [CI]: 1.031-1.329). The variation amplitude of HDL-C in the third trimester is related to the occurrence of GDM and HDCP(GDM:OR = 0.271, 95%CI: 0.095-0.778; HDCP: OR =0.249, 95% CI: 0.075-0.823). TG and TC levels in DCDA twins were significantly higher than that in MCDA twins in the first trimester(TG: p < 0.05, TC: p < 0.05). In the decision tree model for GDM, fasting blood glucose in the first trimester (FBG), TC, and pre-pregnancy BMI were identified as important nodes, while in the HDCP model, pre-pregnancy BMI, TC, and TG were key nodes.Conclusion: Serum lipid levels in twin pregnancies increase gradually during pregnancy. BMI is independently associated with the occurrence of GDM and HDCP. HDL-C may serve as a protective factor for GDM and HDCP. The predictive effect of early blood lipid on GDM and HDCP in twin pregnancy needs further study.

National and international guidelines on the management of twin pregnancies: a comparative review

Twin gestations are associated with increased risk of pregnancy complications. However, high-quality evidence regarding the management of twin pregnancies is limited, often resulting in inconsistencies in the recommendations of various national and international professional societies. In addition, some recommendations related to the management of twin gestations are often missing from the clinical guidelines dedicated to twin pregnancies and are instead included in the practice guidelines on specific pregnancy complications (eg, preterm birth) of the same professional society. This can make it challenging for care providers to easily identify and compare recommendations for the management of twin pregnancies. This study aimed to identify, summarize, and compare the recommendations of selected professional societies from high-income countries on the management of twin pregnancies, highlighting areas of both consensus and controversy. We reviewed clinical practice guidelines of selected major professional societies that were either specific to twin pregnancies or were focused on pregnancy complications or aspects of antenatal care that may be relevant for twin pregnancies. We decided a priori to include clinical guidelines from 7 high-income countries (United States, Canada, United Kingdom, France, Germany, and Australia and New Zealand grouped together) and from 2 international societies (International Society of Ultrasound in Obstetrics and Gynecology and the International Federation of Gynecology and Obstetrics). We identified recommendations regarding the following care areas: first-trimester care, antenatal surveillance, preterm birth and other pregnancy complications (preeclampsia, fetal growth restriction, and gestational diabetes mellitus), and timing and mode of delivery. We identified 28 guidelines published by 11 professional societies from the 7 countries and 2 international societies. Thirteen of these guidelines focus on twin pregnancies, whereas the other 16 focus on specific pregnancy complications predominantly in singletons but also include some recommendations for twin pregnancies. Most of the guidelines are recent, with 15 of the 29 guidelines published over the past 3 years. We identified considerable disagreement among guidelines, primarily in 4 key areas: screening and prevention of preterm birth, using aspirin to prevent preeclampsia, defining fetal growth restriction, and the timing of delivery. In addition, there is limited guidance on several important areas, including the implications of the "vanishing twin" phenomenon, technical aspects and risks of invasive procedures, nutrition and weight gain, physical and sexual activity, the optimal growth chart to be used in twin pregnancies, the diagnosis and management of gestational diabetes mellitus, and intrapartum care.This consolidation of key recommendations across several clinical practice guidelines can assist healthcare providers in accessing and comparing recommendations on the management of twin pregnancies and identifies high-priority areas for future research based on either continued disagreement among societies or limited current evidence to guide care.

The initial number of fetuses in multiple pregnancy before reduction affects perinatal outcomes

OBJECTIVE

In this study, we aimed to evaluate the perinatal outcomes of dichorionic diamniotic (DCDA) twin pregnancies reduced by the fetal reduction (FR) procedure and cases with continuing DCDA twin pregnancies without FR.

MATERIALS AND METHODS

FR performed in a university hospital in the last 10 years was evaluated. Pregnancies reduced to DCDA twin pregnancies by reduction from three or more pregnancies and pregnancies that started with DCDA twins and continued with DCDA twins were compared in terms of perinatal outcomes. In the subgroup analysis, those who were reduced from three-chorionic three-amniotic (TCTA) triplets to DCDA twins and those who were reduced to DCDA twin pregnancies from four or more were compared in terms of perinatal outcomes.

RESULTS

A total of 119 pregnant women were included in the study, 36 patients underwent FR, while 83 patients were DCDA twins who did not undergo FR. The groups were similar in terms of preterm delivery (p = 0.370). There was a higher rate of miscarriage (21.4% vs. 0.0%, p = 0.019) in the group that was reduced to DCDA twins from quadruplet and above pregnancies compared to the group that was reduced from TCTA triplets to DCDA twins. The gestational week at birth was lower in the group reduced to DCDA twins from quadruplets and above pregnancies (31.00 ± 4.31 vs. 34.64 ± 2.88, p = 0.019).

CONCLUSION

The study's results show that the perinatal outcomes of multiple pregnancies with and without FR are the same As the number of reduced fetuses increases, the rates of preterm birth and miscarriage also increase.

Clinical Factors for Predicting Pharmacotherapy in Twin Pregnancies Complicated by Gestational Diabetes Mellitus

Controlling blood glucose levels is the main target in pregnant women with gestational diabetes mellitus (GDM). Twin pregnancies are offered the same screening selection and have the same diagnostic criteria as well as treatment of gestational diabetes as singleton pregnancies, even though the risks for pregnancy complications are increased. The aim of this study was to assess the association between predicting factors, OGTT glucose levels and pharmacotherapy requirements in twin pregnancies with GDM. This retrospective cohort study included 446 GDM patients with twin pregnancies (246 managed with lifestyle modifications and 200 requiring pharmacotherapy) over a time period of 18 years. An evaluation of maternal characteristics and a standardized 75 g oral glucose test (OGGT) for glucose concentrations at fasting, 1 h and 2 h were conduced. OGTT glucose levels at fasting (=0 min, p < 0.01) and 1 h (p < 0.01) were significantly associated with the later requirement of pharmacotherapy. Also, clinical risk factors (pre-pregnancy BMI p < 0.01, multiparity p < 0.05, GDM in previous pregnancy p < 0.01, assisted reproduction p < 0.05) showed a predictive accuracy for insulin therapy in twin pregnancies complicated by GDM, whereas age and chorionicity had no effect. OGTT glucose measures in addition to clinical risk factors are promising variables for risk stratification in mothers with GDM and twin pregnancy.

Induction of Labor in Twins-Double Trouble?

OBJECTIVE

To determine and compare the safety and efficacy of different methods of induction of labor in twin gestations and their effect on maternal and neonatal outcomes.

METHODS

A retrospective observational cohort study was conducted at a single university-affiliated medical center. Patients with a twin gestation undergoing induction of labor at >32 + 0 weeks comprised the study group. Outcomes were compared to patients with a twin gestation at >32 + 0 weeks who went into labor spontaneously. The primary outcome was cesarean delivery. Secondary outcomes included operative vaginal delivery, postpartum hemorrhage, uterine rupture, 5 min APGAR < 7, and umbilical artery pH < 7.1. A subgroup analysis comparing outcomes for the induction of labor with oral prostaglandin E1 (PGE1), IV Oxytocin ± artificial rupture of membranes (AROM), and extra-amniotic balloon (EAB)+ IV Oxytocin was performed. Data were analyzed using Fisher's exact test, ANOVA, and chi-square tests.

RESULTS

268 patients who underwent induction of labor with a twin gestation comprised the study group. 450 patients with a twin gestation who went into labor spontaneously comprised the control group. There were no clinically significant differences between the groups for maternal age, gestational age, neonatal birthweight, birthweight discordancy, and non-vertex second twin. There were significantly more nulliparas in the study group compared to the control group (23.9% vs. 13.8% p < 0.001). The study group was significantly more likely to undergo a cesarean delivery of at least one twin (12.3% vs. 7.5% OR, 1.7 95% CI 1.04-2.85 p = 0.03). However, there was no significant difference in the rate of operative vaginal delivery (15.3% vs. 19.6% OR, 0.74, 95% CI 0.5-1.1 p = 0.16), PPH (5.2% vs. 6.9% OR, 0.75 95% CI 0.39-1.42 p = 0.37), 5-min APGAR scores < 7 (0% vs. 0.2% OR, 0.99 95%CI 0.99-1.00 p = 0.27), umbilical artery pH < 7.1 (1.5% vs. 1.3% OR, 1.12 95% CI 0.3-4.0), or combined adverse outcome (7.8% vs. 8.7% OR, 0.93 95% CI 0.6-1.4 p = 0.85). Furthermore, there were no significant differences in the rates of cesarean delivery or combined adverse outcomes in patients undergoing induction with oral PGE1 compared to IV Oxytocin ± AROM (13.3% vs. 12.5% OR, 1.1 95% CI 0.4-2.0 p = 1.0) (7% vs. 9.3% OR, 0.77 95% CI 0.5-3.5 p = 0.63 ) or EAB+ IV Oxytocin (13.3% vs. 6.9% OR, 2.1 95% CI 0.1-2.1 p = 0.53) (7% vs. 6.9% OR, 1.4 95% CI 0.15-3.5 p = 0.5) or between patients undergoing induction of labor with IV Oxytocin ± AROM and EAB+ IV Oxytocin (12.5% vs. 6.9% OR, 2.1 95% CI 0.1-2.4 p = 0.52) (9.3% vs. 6.9% OR, 0.98 95% CI 0.2-4.7 p = 0.54). There were no cases of uterine rupture in our study.

CONCLUSIONS

Induction of labor in twin gestations is associated with a two-fold increased risk of cesarean delivery, although this is not associated with adverse maternal or neonatal outcomes. Furthermore, the method of induction of labor used does not affect the chances of success nor the rate of adverse maternal or neonatal outcomes.

Clinical practice guidelines on the use of aspirin in pregnancy: Systematic review

BACKGROUND

Placental related disorders, including preeclampsia and fetal growth restriction (FGR) are among the main determinants of adverse maternal and perinatal outcomes in both singleton and twin pregnancies. In view of its relevance, aspirin administration is commonly recommended to women at high risk for preeclampsia or FGR by the various national and international guidelines.

OBJECTIVES

To establish the clinical heterogeneity among the clinical practice guidelines (CPGs) on aspirin use in pregnancy and to investigate the quality of these CPGs.

METHODS

We performed a systematic review of Clinical practice guidelines on main databases searching for all peer-reviewed guidelines into the literature, analyzing the following aspects related to use of aspirin in pregnancy: indications for aspirin administration, dosage, starting of therapy, ending of therapy, safety and side effects. The assessment of risk of bias and quality assessment of the included CPGs were performed using "The Appraisal of Guidelines for REsearch and Evaluation (AGREE II)" tool.

RESULTS

16 CPGs were included. There was an overall general agreement among the published CPGs as regards to the indication for aspirin intake in pregnancy, with prior preeclampsia, chronic hypertension, autoimmune disease, and diabetes mellitus type 1 or 2 recognized as solitary major risk factors for Aspirin administration in 93.7% (15/16) of CPGs. There was heterogeneity in the recommendations provided by the different CPGs as regards the gestational age at which aspirin should be commenced.

CONCLUSION

There is general agreement in the reported indications for aspirin intake in pregnancy, with prior preeclampsia and maternal medical co-morbidity associated with increased risk of preeclampsia being the major indications for aspirin intake. Conversely, there was heterogeneity in the recommended dose, gestational age at initiation and discontinuation of therapy among the different CPGs.

Different pathways for preterm birth between singleton and twin pregnancies: a population-based registry study of 481 176 nulliparous women

OBJECTIVE

To explore the contribution of pregnancy-related complications on the prevalence of extremely, very and late preterm births in singleton and twin pregnancies. To study the risk of spontaneous preterm birth in twin pregnancies compared with singleton pregnancies.

DESIGN

Population-based registry study.

SETTING

Medical birth registry of Norway and Statistics Norway.

POPULATION

Nulliparous women with singleton (n = 472 449) or twin (n = 8727) births during 1999-2018.

METHODS

Prevalence rates of pregnancy-related complications for extremely, very and late preterm birth in twin and singleton pregnancies were calculated with 95% confidence intervals. Multivariable logistic regression was applied to assess odds ratios for preterm birth, adjusted for obstetric and socio-economic factors.

MAIN OUTCOME MEASURES

Extremely preterm (<28⁺⁰  weeks of gestation), very preterm (28⁺⁰ -33⁺⁶  weeks of gestation) and late preterm (34⁺⁰ -36⁺⁶  weeks of geatation) birth.

RESULTS

Preterm birth was significantly more prevalent in twin pregnancies than in singleton pregnancies in all categories: all preterm (54.7% vs 6.1%), extremely preterm (3.6% vs 0.4%), very preterm (18.2% vs 1.4%) and late preterm (33.0% vs 4.3%) births. Stillbirth, congenital malformation and pre-eclampsia were more prevalent in twin pregnancies than in singleton pregnancies, but the prevalence of complications differed in the three categories of preterm birth. Pre-eclampsia was more prevalent in singleton than in twin pregnancies ending in extremely and very preterm birth. The adjusted odds of spontaneous preterm live birth were between 19- and 54-fold greater in twin pregnancies than in singleton pregnancies.

CONCLUSIONS

Singleton and twin pregnancies seem to have different pathways leading to extremely, very and late preterm birth.

Optimal cutoffs of growth discordance for the risk of preeclampsia in twin pregnancies: A single-center retrospective cohort study

Objective

To explore the optimal cutoffs of growth discordance for the risk of preeclampsia in twin pregnancies.

Methods

A retrospective cohort study in a university hospital which included twins delivered from February 2013 to September 2020. Restrictive cubic spline (RCS) model was applied to the trend of intertwin birthweight difference (BWD) with the risk of preeclampsia. Logistic regression and subgroup analysis were performed to find the cut-off with statistical significance and clinical meaningfulness.

Results

A total of 2,631 women pregnant with twins were enrolled. RCS showed a nonlinear upward trend of preeclampsia with BWD, and the BWD of 15% was the initial rising point. With the confounders adjusted, only the group with BWD ≥ 25% was found to be significantly associated with an increased risk of preeclampsia (adjusted odds ratio [aOR], 2.44; 95% confidence interval [CI]: 1.74-3.42). Additionally, subgroup analysis showed that both monochorionic (MC) and small for gestational age (SGA) twins were more likely to complicate with preeclampsia.

Conclusion

The growth discordance of 15% during pregnancy may be the preventive point of preeclampsia, and 25% may be the interventional point.

Analysis of the characteristics of blood lipid metabolism in twin pregnancy

To investigate the characteristics of blood lipid metabolism in twin pregnancy combined with gestational diabetes mellitus (GDM) or pregnancy-induced hypertension (PIH). This study retrospectively analyzed 96 cases of twin pregnancy and 232 cases of full-term singleton pregnancy. General data and blood lipid levels, including triglyceride (TG) and total cholesterol (TC), between twin and singleton pregnancies were compared. Blood lipid levels between GDM (PIH) and non-GDM (non-PIH) groups in twin pregnancy were compared. The TG level for twin pregnancy was higher than that for singleton pregnancy (p<0.05), while there was no significant difference in the TC level between them (p>0.05). The TG level in the GDM group was higher than that in the non-GDM group (p<0.05), while the TC level in the GDM group was not different from that in the non-GDM group (p>0.05). The TG level in the PIH group was higher than that in the non-PIH group (p<0.05), while there was no difference in the TC level between them (p>0.05). Logistic regression analysis showed that age was a risk factor for GDM and PIH in singleton and twin pregnancies. The lipid levels in twin pregnancy increased with the increase of gestational age, and the TG level in twin pregnancy complicated with GDM or PIH was higher than that in twin pregnancy without GDM or PIH, indicating that the blood lipid metabolism was related to the occurrence of GDM and PIH in twin pregnancy to some extent.

Histopathologic evaluation of dichorionic twin placentas in unassisted and in vitro fertilized pregnancies affected by preeclampsia

OBJECTIVE

Pregnancies achieved with assisted reproductive technology have an increased risk of multiple gestations, preeclampsia, and placental morphologic abnormalities. Inflammatory processes affect dichorionic twin pregnancies disproportionately more than singleton gestations and have been associated with adverse pregnancy outcomes, such as fetal growth restriction and preeclampsia. Our objective is to investigate the placental morphology of dichorionic twin pregnancies complicated by preeclampsia conceived with in vitro fertilization (IVF) versus unassisted.

METHODS

This is a retrospective analysis of placentas from dichorionic twin pregnancies affected by preeclampsia conceived with IVF versus without assistance from 2010 to 2016 at a tertiary care university hospital. Placental pathology findings were analyzed both independently and in aggregate stratified into composite outcome scores using a modified placental synoptic framework. Individual placental abnormalities were grouped into composite categories based on the site of origin: anatomic placental abnormalities; maternal vascular malperfusion; placental villous maldevelopment; fetal vascular malperfusion; chronic utero-placental separation; maternal-fetal interface disturbance; inflammation of infectious etiology; and inflammation of idiopathic etiology. Placental histopathological statistical analysis was performed using Fisher's exact test. Demographic variables and pregnancy outcomes were compared between groups using the Student's t test or Mann-Whitney U test, where appropriate. p < .05 defined statistical significance.

RESULTS

Of 117 dichorionic twin pregnancies, 60 resulted from IVF (Group A) and 57 were conceived without assistance (Group B). Patients in Group A were older (36 [29-37] vs. 33 [32-38] respectively; p = .042) and less parous (18.3% vs. 38.6% percent parous in Group A and Group B, respectively p = .009) than Group B, respectively. No differences were found between groups regarding mode of delivery, gestational age at delivery, placental weight/birthweight, fetal growth restriction, and discordance of fetal growth. There were significantly more inflammatory changes of unknown etiology and composite inflammatory abnormalities in Group A versus Group B (26.7% vs. 10.5%, p = .02). The cumulative number of inflammatory abnormalities per patient had a significantly different distribution among groups (p = .005), and Composite Chronic Inflammation and Infection were found to be significantly more abundant in Group A versus Group B (p = .02). The distribution of placental composite anatomic placental abnormalities, maternal vascular malperfusion, placental villous maldevelopment, fetal vascular malperfusion, chronic utero-placental separation, or maternal-fetal interface disturbance was not statistically different between groups. The distribution of placental abnormalities was not different between groups for any individually analyzed pathological condition. Due to the relatively small sample size, adjustment for potential confounders was not performed.

CONCLUSION

Dichorionic twin pregnancies affected by preeclampsia are associated with more placental inflammatory abnormalities if conceived with IVF versus unassisted. Further research is needed to ascertain the underlying mechanisms of these observed differences.

Intertwin growth discordance throughout gestation and hypertensive disorders of pregnancy

BACKGROUND

Previous studies have established the association between intertwin birthweight discordance and hypertensive disorders of pregnancy. However, longitudinal fetal size discordance concerning gestational hypertension or preeclampsia remains unclear.

OBJECTIVE

This study aimed to compare the patterns of estimated fetal weight discordance throughout gestation among normotensive women, women with gestational hypertension, and women with preeclampsia and to evaluate the association between crown-rump length discordance at 11 to 14 weeks of gestation and hypertensive disorders of pregnancy.

STUDY DESIGN

This was a retrospective cohort study of women with twin pregnancies who had antenatal care visits and delivered at a tertiary hospital between January 2013 and June 2021. The crown-rump length was measured at 11 to 14 weeks of gestation. Estimated fetal weight was calculated based on ultrasound examinations of fetal biometrics at 16 to 18, 20 to 24, 28 to 32, and ≥34 weeks of gestation, respectively. Crown-rump length and estimated fetal weight discordances were calculated: (larger crown-rump length - smaller crown-rump length)/larger crown-rump length × 100% and (larger estimated fetal weight - smaller estimated fetal weight)/larger estimated fetal weight × 100%, respectively. Multiple imputation was used to handle missing data, and all models accounted for the imputation. Multilevel model analysis was used to compare the differences in estimated fetal weight discordances throughout gestation among normotensive women, women with gestational hypertension, and women with preeclampsia. Generalized linear models were used to evaluate the association between crown-rump length discordance and hypertensive disorders of pregnancy, assuming a Poisson distribution. The possible nonlinear relationship between continuous crown-rump length discordance and hypertensive disorders of pregnancy was examined by generalized additive models. All analyses were stratified by chorionicity.

RESULTS

Of the 3280 women with twin pregnancies who met the inclusion criteria, 187 (5.7%) developed gestational hypertension, and 436 (13.3%) developed preeclampsia, including 125 (3.8%) early-onset preeclampsia and 311 (9.5%) late-onset preeclampsia. In women with dichorionic twin pregnancies, compared with normotensive women, a substantial progression of estimated fetal weight discordance throughout pregnancy was identified in women who developed preeclampsia, and a large progression of estimated fetal weight discordance in late pregnancy was identified in women who developed gestational hypertension. In women with monochorionic twin pregnancies, estimated fetal weight discordances were more progressive from 20 to 24 weeks of gestation onward in women who developed preeclampsia than in normotensive women. Crown-rump length discordance at 11 to 14 weeks of gestation was associated with an increased risk of preeclampsia (relative risk, 1.03; 95% confidence interval, 1.00-1.05), particularly early-onset preeclampsia (relative risk, 1.09; 95% confidence interval, 1.04-1.13). A crown-rump length discordance of ≥10% had 1.2 times the increased risk of developing early-onset preeclampsia (relative risk, 2.27; 95% confidence interval, 1.28-4.03). This association was identified in dichorionic twins, but not in monochorionic twins.

CONCLUSION

Our study demonstrated distinct growth discordant patterns among normotensive women, women with gestational hypertension, and women with preeclampsia in twin pregnancies. Intertwin crown-rump length discordance at 11 to 14 weeks of gestation was associated with an increased risk of preeclampsia, especially early-onset preeclampsia in dichorionic twin pregnancies, with a dose-response pattern.

Gestational hypertensive disease and small for gestational age infants in twin pregnancy: A systematic review and meta-analysis

AIM

The review is to explore the connection between gestational hypertension diseases (GHD) and small for gestational age (SGA) in twin pregnancies.

METHODS

According to the recommendations of PRISMA, relevant studies were systematically searched through PubMed, Web of Science, Cochrane Library, Embase from inception until January 16, 2022. Subgroup analysis was performed according to chorionicity and diagnostic criteria of SGA. Odds ratios (OR) were assessed to judge the link between GHD and SGA in twin pregnant women. A random-effect model was used to estimate the pooled hazard ratio when there was significant heterogeneity (I²  > 50%); otherwise, a fixed-effect model was conducted.

RESULTS

Seven articles containing 470 589 twin pregnant women were included. The increased risk of SGA was connected to the twin pregnancies complicated with GHD (OR = 1.57, 95% confidence interval [CI] = 1.10-2.24, p = 0.01). After subgroup analysis, the connection between SGA and GHD had no statistical significance (OR = 1.17, 95% CI = 0.95-1.44, p = 0.14) when the enrolled studies using the SGA diagnosis referred to singleton birth weight, but significant (OR = 2.14, 95% CI = 1.77-2.60, p<0.001) in the group using the SGA diagnosis referred to twin birth weight. Stratified by chorionicity, SGA was relevant to GHD in the dichorionic (DC) group (OR = 1.68, 95% CI = 1.17-2.42, p = 0.005), while not in the monochorionic (MC) group (OR = 1.68, 95% CI = 0.93-3.03, p = 0.09). More future articles are warranted to confirm these outcomes.

CONCLUSIONS

Our review demonstrated that GHD in DC twin pregnancies was related to an enlarged risk of SGA. Two SGA diagnosis references led to different results. Twin pregnancies complicated with GHD were at significantly higher risk of SGA when twin birth weight reference was used.

Neutrophil Gelatinase-Associated Lipocalin and Hypertensive Disorders of Pregnancy: A Cohort Study in Twin Pregnancies

Hypertensive disorders complicate more than 10% of twin pregnancies. Several studies showed increased neutrophil gelatinase-associated lipocalin (NGAL) values in women with singleton pregnancies and preeclampsia. This study aimed to assess NGAL values in twin pregnancies complicated by hypertensive disorders. We conducted a study of 242 consecutive twin pregnancies at the Medical University of Vienna. Serum NGAL was evaluated twice during pregnancy and once in the postpartum period. Furthermore, serum NGAL values were compared between women who developed hypertensive disorders and those who had normal blood pressure. In all twin pregnancies, mean NGAL values increased significantly from the first to the second visit (p = 0.004) and, further, after delivery (p < 0.001). NGAL was significantly higher in pregnancies that developed pregnancy hypertension or preeclampsia when compared to the control group at the first visit (109.2 ± 48.9 ng/mL vs. 91.9 ± 29.4 ng/mL, p = 0.04, respectively). The predictive power of first visit NGAL values for development of pregnancy hypertension or preeclampsia was evaluated. When using a cut-off value of 115 ng/mL, we obtained a sensitivity of 45% with a specificity of 77%. We conclude that women with twin pregnancies who develop hypertensive disorders of pregnancy showed increased NGAL values at 11−16 weeks.

Maternal cardiac function in twin pregnancy at 19-23 weeks' gestation

OBJECTIVES

To compare maternal cardiovascular indices at 19-23 weeks' gestation between twin and singleton pregnancies and assess the impact of chorionicity on these parameters.

METHODS

This was a prospective observational study in women with twin pregnancy attending for a hospital visit at 19 + 1 to 24 + 3 weeks' gestation. This visit included recording of maternal demographic characteristics and medical history and maternal cardiovascular assessment. In a previous study of 4795 women with singleton pregnancies at 19-23 weeks' gestation, multivariable linear regression models were fitted between the various cardiovascular indices and elements of maternal characteristics and medical history. In this study, we calculated multiples of the median (MoM) and delta values according to the singleton models and assessed the distributional properties of these MoM and delta values in twin as compared with singleton pregnancies.

RESULTS

The study population of 155 women with twin pregnancy included 86 dichorionic and 69 monochorionic cases. In general, there was a similar distribution of maternal cardiovascular indices in monochorionic and dichorionic twin pregnancies. In both types of twin pregnancy, compared with singleton pregnancy, there was an increase in isovolumetric relaxation time, left atrial area and myocardial performance index, and a decrease in mitral valve E/A. Left ventricular mass indexed for body surface area and relative wall thickness were also increased in twin compared with singleton pregnancy. The magnitude of the increase in left atrial area was greater in dichorionic compared with monochorionic pregnancies. Additionally, mitral valve E was decreased and left atrial volume was increased in dichorionic but not in monochorionic pregnancies, while isovolumetric contraction time was increased in monochorionic but not in dichorionic pregnancies. Left ventricular myocardial deformation was similar between twin and singleton pregnancies.

CONCLUSIONS

In twin pregnancies at mid-gestation, maternal systolic and diastolic function is reduced when compared with singletons. The patterns of cardiovascular adaptation are similar between monochorionic and dichorionic pregnancies and resemble those reported in uncomplicated singleton pregnancy later in gestation. © 2022 International Society of Ultrasound in Obstetrics and Gynecology.

Maternal echocardiographic changes in twin pregnancies with and without pre-eclampsia

OBJECTIVE

Twin pregnancies are at increased risk of developing hypertensive disorders of pregnancy (HDP) compared with singleton pregnancies, resulting in a substantially higher rate of maternal and perinatal complications. The strain caused by twin pregnancy on the maternal cardiovascular system has not been studied extensively. The objective of this study was to evaluate the changes in maternal cardiac morphology and diastolic function in a cohort of women with normotensive and those with hypertensive twin pregnancies.

METHODS

This was a cross-sectional study conducted at a tertiary referral university center. Women with singleton or twin pregnancy were enrolled prospectively to undergo maternal transthoracic echocardiography throughout pregnancy. Multiples of the median (MoM) were calculated for each index using a reference group of uncomplicated singleton pregnancies (n = 411) in order to adjust for changes associated with gestational age. Cardiac findings were indexed for body surface area and compared among normotensive twin pregnancies, singleton pregnancies complicated by HDP and twin pregnancies complicated by HDP.

RESULTS

The total cohort included 119 HDP singleton pregnancies, 52 normotensive twin pregnancies and 24 HDP twin pregnancies. Left ventricular mass index (LVMi) MoM (median (interquartile range)) did not differ between singleton pregnancies complicated by HDP and normotensive twin pregnancies, but was significantly higher in HDP twin compared with HDP singleton pregnancies (1.31 (1.08-1.53) vs 1.17 (0.98-1.35), P = 0.032). Two diastolic indices, left atrial volume index MoM (1.12 (0.66-1.38) vs 0.65 (0.55-0.84), P = 0.003) and E/e' MoM (1.29 (1.09-1.54) vs 0.99 (0.99-1.02), P = 0.036), were significantly higher in HDP twin compared with normotensive twin pregnancies. In normotensive twin compared with HDP singleton pregnancies, stroke volume index (SVi) MoM was higher (1.20 (1.03-1.36) vs 1.00 (0.81-1.15), P = 0.004) and total vascular resistance index (TVRi) was lower (0.73 (0.70-0.86) vs 1.29 (1.04-1.56), P < 0.0001). In contrast, SVi MoM was lower (1.10 (1.02-1.35) vs 1.20 (1.03-1.36), P = 0.018) and TVRi was higher (1.00 (0.88-1.31) vs 0.73 (0.70-0.86), P = 0.029) in HDP twin compared with normotensive twin pregnancies.

CONCLUSION

The maternal cardiovascular system is altered severely in twin pregnancy with or without HDP. Despite the low total vascular resistance, cardiac changes in normotensive twin pregnancies are comparable to those seen in singleton pregnancies complicated by HDP, reflecting the high cardiovascular demand imposed by twin pregnancy. © 2022 International Society of Ultrasound in Obstetrics and Gynecology.

A New Model for the Predicting the Risk of Preeclampsia in Twin Pregnancy

Objective

We aimed to develop an effective nomogram model for predicting the risk of preeclampsia in twin pregnancies.

Methods

The study was a retrospective cohort study of women pregnant with twins who attended antenatal care and labored between January 2015 and December 2020 at the Fujian Maternity and Child Health Hospital, China. We extracted maternal demographic data and clinical characteristics. Then we performed the least absolute shrinkage and selection operator regression combined with clinical significance to screen variables. Thereafter, multivariate logistic regression was used to construct a nomogram that predicted the risk of preeclampsia in twin pregnancies. Finally, the nomogram was validated using C-statistics (C-index) and calibration curves.

Results

A total of 2,469 women with twin pregnancies were included, of whom 325 (13.16%) had preeclampsia. Multivariate logistic regression models revealed that serum creatinine, uric acid, mean platelet volume, high-density lipoprotein, lactate dehydrogenase, fibrinogen, primiparity, pre-pregnancy body mass index, and regular prenatal were independently associated with preeclampsia in twin pregnancies. The constructed predictive model exhibited a good discrimination and predictive ability for preeclampsia in twin pregnancies (concordance index 0.821).

Conclusion

The model for the prediction of preeclampsia in twin pregnancies has high accuracy and specificity. It can be used to assess the risk of preeclampsia in twin pregnancies.

Screening for preeclampsia in twin pregnancies

Twin pregnancies are an important risk factor for preeclampsia, a hypertensive disorder of pregnancy that is associated with a significant risk of maternal and perinatal morbidity. Given the burden of preeclampsia, the identification of women at high risk in early pregnancy is essential to allow for preventive strategies and close monitoring. In singleton pregnancies, the risk factors for preeclampsia are well established, and a combined first-trimester prediction model has been shown to adequately predict preterm disease. Furthermore, intervention with low-dose aspirin at 150 mg/day in those identified as high-risk reduces the rate of preterm preeclampsia by 62%. In contrast, risk factors for preeclampsia in twin pregnancies are less established, the proposed screening models have shown poor performance with high false-positive rates, and the benefit of aspirin for the prevention of preeclampsia is not clearly demonstrated. In this review, we examine the literature assessing prediction and prevention of preeclampsia in twin pregnancies.

Incidence and Implications of Twin Gestational Surrogacy at Two Large U.S. Military Hospitals: A 10-Year Retrospective Cohort Study

INTRODUCTION

Individuals seeking a gestational surrogate often turn to U.S. military dependents due to favorable insurance coverage. Surrogate pregnancies, including multiple gestations, may be at increased risk for adverse outcomes. The objectives of this study were to determine the incidence of surrogacy in a twin population conceived by assisted reproductive technology (ART), assess the impact on the military healthcare system, and determine if there is an increased rate of complications in twin surrogacy pregnancies.

MATERIALS AND METHODS

We conducted a 10-year retrospective cohort study of ART-conceived twin gestations at two military hospitals. Charts were reviewed for demographic data, surrogacy status, and obstetric complications. Number of prenatal visits and formal sonograms were tabulated for surrogate pregnancies. Complication rates were compared between groups using Fisher's exact test.

RESULTS

Over the 10-year period, 36 of the 249 pregnancies were identified as gestational surrogates, equating to a rate of 14.4%. Surrogate mothers were younger than non-surrogates (29.58 years vs. 33.11 years, P < .001). Care of surrogate pregnancies required a total of 306 prenatal visits and 98 formal ultrasounds. The incidence of gestational diabetes was higher among surrogates compared to other ART-conceived twin pregnancies at 27.8% vs. 12.2% (P < .05), while other complications did not significantly differ.

CONCLUSIONS

Approximately one in seven ART-conceived twin gestations were surrogacy pregnancies, requiring significant clinical resources. The incidence of gestational diabetes was higher among surrogate gestations.

Prevention of preeclampsia with aspirin

Preeclampsia is defined as hypertension arising after 20 weeks of gestational age with proteinuria or other signs of end-organ damage and is an important cause of maternal and perinatal morbidity and mortality, particularly when of early onset. Although a significant amount of research has been dedicated in identifying preventive measures for preeclampsia, the incidence of the condition has been relatively unchanged in the last decades. This could be attributed to the fact that the underlying pathophysiology of preeclampsia is not entirely understood. There is increasing evidence suggesting that suboptimal trophoblastic invasion leads to an imbalance of angiogenic and antiangiogenic proteins, ultimately causing widespread inflammation and endothelial damage, increased platelet aggregation, and thrombotic events with placental infarcts. Aspirin at doses below 300 mg selectively and irreversibly inactivates the cyclooxygenase-1 enzyme, suppressing the production of prostaglandins and thromboxane and inhibiting inflammation and platelet aggregation. Such an effect has led to the hypothesis that aspirin could be useful for preventing preeclampsia. The first possible link between the use of aspirin and the prevention of preeclampsia was suggested by a case report published in 1978, followed by the first randomized controlled trial published in 1985. Since then, numerous randomized trials have been published, reporting the safety of the use of aspirin in pregnancy and the inconsistent effects of aspirin on the rates of preeclampsia. These inconsistencies, however, can be largely explained by a high degree of heterogeneity regarding the selection of trial participants, baseline risk of the included women, dosage of aspirin, gestational age of prophylaxis initiation, and preeclampsia definition. An individual patient data meta-analysis has indicated a modest 10% reduction in preeclampsia rates with the use of aspirin, but later meta-analyses of aggregate data have revealed a dose-response effect of aspirin on preeclampsia rates, which is maximized when the medication is initiated before 16 weeks of gestational age. Recently, the Aspirin for Evidence-Based Preeclampsia Prevention trial has revealed that aspirin at a daily dosage of 150 mg, initiated before 16 weeks of gestational age, and given at night to a high-risk population, identified by a combined first trimester screening test, reduces the incidence of preterm preeclampsia by 62%. A secondary analysis of the Aspirin for Evidence-Based Preeclampsia Prevention trial data also indicated a reduction in the length of stay in the neonatal intensive care unit by 68% compared with placebo, mainly because of a reduction in births before 32 weeks of gestational age with preeclampsia. The beneficial effect of aspirin has been found to be similar in subgroups according to different maternal characteristics, except for the presence of chronic hypertension, where no beneficial effect is evident. In addition, the effect size of aspirin has been found to be more pronounced in women with good compliance to treatment. In general, randomized trials are underpowered to investigate the treatment effect of aspirin on the rates of other placental-associated adverse outcomes such as fetal growth restriction and stillbirth. This article summarizes the evidence around aspirin for the prevention of preeclampsia and its complications.

Prediction of twin pregnancy preeclampsia based on clinical risk factors, early pregnancy serum markers, and uterine artery pulsatility index

Objectives:

To investigate whether a combination of clinical risk factors, early pregnancy serum markers, and uterine artery pulsatility index (UTPI) can be used to predict twin preeclampsia (PE).

Methods:

This case control study included women with twin pregnancies who had undergone obstetrics treatments and gave birth at the Huzhou Maternity and Child Health Care Hospital from October 2018 to November 2020. Patients with PE comprised study group, and patients without PE comprised control group based on selection criteria and a 1:1 ratio. Statistical analysis was performed using clinical risk factors, early pregnancy serum markers, and UTPIs, and the area under the receiver operating curve (AUC. Sensitivity, and the specificity of different combinations of these variables were calculated to predict PE in women with twin pregnancy.

Results:

Logistic regression analysis revealed four independent predictors for the onset of PE during twin pregnancies: first delivery (OR, 7.51; P=0.045), conception method (OR, 7.11; P=0.036), β-HCG level (per SD OR, 2.73; P=0.026), and UTPI (OR, 0.17; P=0.043). First-delivery and IVF pregnancy methods both lead to a 7-fold increase in the PE risk during twin pregnancies. Every one sigma (standard deviation) increase in the β-HCG level led to a 2.73-fold increase in the PE risk. Every UTPI increment by 1.0 reduces the risk of PE by 83%. The prediction efficiencies were based on an AUC of 0.837, a sensitivity of 69%, and a specificity of 92% for the clinical risk factors; an AUC of 0.800, a sensitivity of 81%, and specificity of 78% for the β-HCG level, and an AUC of 0.814, a sensitivity of 88%, and a specificity of 65% for the UTPI. AUC was 0.928, sensitivity 85%, and a specificity 88% after applying the three types of indicators together for prediction.

Conclusions:

By combining early pregnancy serum markers (β-HCG), and UTPI, the predictive value for PE during twin pregnancy is improved together with its sensitivity and specificity.

Gestational hypertensive disease and birthweight discordance in twin pregnancies: a systematic review and meta-analysis

INTRODUCTION

The objective of this systematic review was to explore the association between gestational hypertensive disease (GHD) and birthweight discordance in twin pregnancies.

METHODS

PubMed, Embase, Web of Science and Cochrane Library were systematically searched for studies reporting the risk of birthweight discordance in twin pregnancies complicated compared with those not complicated by GHD from establishment until July 2021. Risk of bias was assessed with the Newcastle-Ottawa Scale. According to the classification of GHD, sub-group analyses reporting cases with gestational hypertension (GH), chronic hypertension (CH) and preeclampsia (PE) were performed separately. Stratification by twin chorionicity (dichorionic (DC) and monochorionic (MC)) was also conducted. When there was substantial heterogeneity (I² ≥ 50%), the random effect mode was used to estimate the pooled risk ratio, otherwise the fixed effect model was used.

RESULTS

Nine studies (303,204 twin pregnancies) were included. GHD (OR 1.45, 95% CI 1.41-1.49) was a risk factor for intertwin birthweight discordance [PE (OR 1.69, 95% CI 1.33-2.16); CH (OR 1.59, 95% CI 1.46-1.73); GH (OR1.45, 95%Cl 1.10-1.92]. After stratification, birthweight discordance was related to GHD (OR 2.51, 95% CI 2.01-3.14), GH (OR 2.08, 95% CI 1.33-3.25) and PE (OR 2.74, 95% CI 2.09-3.61) in DC pregnancies, but no longer associated with GHD and PE in MC group.

CONCLUSIONS

Twin gestations complicated with GHD, especially in DC pregnancies, were at significantly higher risk of birthweight discordance.

Low-dose aspirin for primary prevention of adverse pregnancy outcomes in twin pregnancies: an observational cohort study based on propensity score matching

Background

Since the effectiveness of low-dose aspirin (LDA) in twin pregnancies is uncertain, we aimed to preliminarily assess whether LDA is beneficial in preventing preeclampsia in twin pregnancies.

Methods

This study is an observational study in two hospitals in China. Among 932 women, 277 in the First Affiliated Hospital of Chongqing Medical University were routinely treated with aspirin (100 mg daily) from 12 to 16 weeks to 35 weeks of gestational age, while 655 in Chongqing Health Center for Women and Children were not taking aspirin during pregnancy. We followed each subject and the individual details were recorded.

Results

LDA significantly reduced the risk of preeclampsia (RR 0.48; 95% CI 0.24–0.95) and preterm birth 34 weeks (RR 0.50; 95% CI 0.29–0.86) and showed possible benefits to lower the rate of SGA babies (RR 0.74; 95% CI 0.55–1.00). Moreover, the risk of postpartum hemorrhage was not increased by LDA (RR 0.89; 95% CI 0.35–2.26).

Conclusions

Treatment with low-dose aspirin in twin pregnancies could offer some protection against adverse pregnancy outcomes in the absence of significantly increased risk of postpartum hemorrhage.

Trial registration

Chinese Clinical Trial Registry (ChiCTR); ChiCTR-OOC-16008203, Retrospectively registered date: April 1st, 2016;

Supplementary Information

The online version contains supplementary material available at 10.1186/s12884-021-04217-2.

Incidence of chest X-ray abnormalities early in the third trimester of twin pregnancy and its relationship with the subsequent development of preeclampsia

AIM

To clarify the incidence of abnormal findings on chest X-ray (CXR) early in the third trimester of twin pregnancy and its relationship with the development of preeclampsia and preeclampsia-related diseases.

METHODS

This was a retrospective cohort study conducted among women with twin pregnancies who underwent chest radiography for preoperative screening early in the third trimester and delivered at our center at >34 weeks' gestation from 2013 to 2017. The primary outcome was the incidence of positive CXR findings, defined either as cardiomegaly or blunting of the costophrenic angle. The secondary outcome was the incidence of maternal complications, including preeclampsia; hemolytic, elevated liver enzymes, and low platelet syndrome; eclampsia; cerebrovascular disease; and placental abruption. We evaluated the significance of positive CXR findings, in addition to confounding factors, in the subsequent development of preeclampsia.

RESULTS

During the study period, 358 twin pregnancies were identified, and 330 were finally enrolled. The incidence of positive CXR findings was 18.2%. The incidence of preeclampsia in the CXR-positive group was 36.7% (22/60), which was significantly higher than that in the CXR-negative group (7.0% [19/270]) (p < 0.01). Moreover, positive CXR findings were independently associated with subsequent preeclampsia (adjusted odds ratio: 9.15, 95% confidence interval: 4.13-20.3).

CONCLUSION

In twin pregnancies, the incidence of CXR abnormalities early in the third trimester was 18.2%, even without the development of hypertension. This should be considered a significant risk factor for subsequent preeclampsia.

Establishing the Most Accurate Due Date in Dichorionic Twin Gestations by First and Second Trimester Ultrasound

OBJECTIVE

To determine the optimal sonographic dating of dichorionic gestations.

MATERIALS AND METHODS

We reviewed dichorionic pregnancies conceived with assisted reproductive technologies (ART) at 2 institutions between 2006-2016, excluding fetuses with major anomalies. Gestational age was calculated with smaller, larger, and mean of the crown-rump lengths (CRL) and biometry midgestation and compared to the ART age. The mean and mean absolute deviation of the observed gestational age from the ART age was calculated to assess accuracy, precision, and presence of bias. The incidence of small for gestational age using the smaller and larger CRLs was compared to the ART age via McNemar's test.

RESULTS

Based on 140 ultrasounds, the CRL from the smaller twin best approximates the true gestational age with least bias compared to the larger twin or average (mean absolute deviation: 2.8, mean deviation: -0.1 [95% CI: -0.4, 0.2] versus 2.7, -0.9 [-1.1, -0.6] and 2.9, -1.5 [-1.8, -1.3], in days, respectively). Based on 165 ultrasounds, biometry from the smaller fetus is least accurate compared to the larger or mean (11.8, 2.5 [1.5, 3.6] versus 11.7, 0.8 [-0.3, 1.8] and 11.9, -1.0 [-2.0, 0.04], respectively). The incidence of small for gestational age neonates did not differ from the true rate using either the CRL from the larger or smaller twin (p > .05).

CONCLUSION

In ART dichorionic gestations, ultrasound of the smaller fetus is most accurate in establishing gestational age in the first trimester but least accurate in the second, though all methods performed well with little clinical difference.

Predictive value of the sFlt-1/PlGF ratio for preeclampsia in twin pregnancies: a retrospective study

Objective: This study aimed to investigate the efficiency of the soluble Fms-like tyrosine kinase 1 (sFlt-1)/placental growth factor (PlGF) ratio in predicting preeclampsia (PE) within 4 weeks in twin pregnancies.Methods: Seventy-eight women with serum angiogenic markers measured at 28 + 0 to 30 + 6 weeks of gestation were enrolled. A receiver-operating characteristic curve was used to determine the sFlt-1/PlGF ratio threshold to predict PE.Results: A cutoff value for the sFlt-1/PlGF ratio of 22.2 predicted PE presence within 4 weeks.Conclusion: An sFlt-1/PlGF ratio of ≤22.2 is potentially indicative of PE absence within 4 weeks in twin pregnancies.

First-Trimester Screening for Gestational Diabetes Mellitus in Twin Pregnancies

We previously reported a logistic regression model for prediction of GDM from maternal characteristics and medical history in 75,161 singleton pregnancies. In this study of 1376 twin and 13,760 singleton pregnancies recruited at 11-13 weeks' gestation, we extend the model to include terms for twin pregnancies. We found the respective odds of GDM in dichorionic and monochorionic twin pregnancies to be 1.36 (95% CI: 1.02-1.81) and 2.78 (95% CI: 1.72-4.48) times higher than in singleton pregnancies. In both singleton and twin pregnancies, the risk for GDM increased with maternal age and weight and birth weight z-score of a baby in a previous pregnancy and is higher in women with a previous pregnancy complicated by GDM; in those with a first- or second-degree relative with diabetes mellitus; in women of Black, East Asian, and South Asian racial origin; and in pregnancies conceived through the use of ovulation-induction drugs. In singleton pregnancies, at 10% and 20% false-positive rate, the detection rate was 43% and 58%, respectively. In twin pregnancies, using risk cut-offs corresponding to 10% and 20% false-positive rates in singletons, the respective false-positive rates were 27% and 47%, and the detection rates were 63% and 81%.

Cell-free DNA testing of maternal blood in screening for trisomies in twin pregnancy: updated cohort study at 10-14 weeks and meta-analysis

OBJECTIVE

To expand the limited knowledge on cell-free DNA (cfDNA) analysis of maternal blood for trisomies 21, 18 and 13 in twin pregnancy by updating the data from The Fetal Medicine Foundation (FMF) on prospective first-trimester screening and those identified in a systematic review of the literature.

METHODS

The FMF data were derived from prospective screening for trisomies 21, 18 and 13 in twin pregnancies at 10 + 0 to 14 + 1 weeks' gestation using the Harmony® prenatal test. A search of MEDLINE, EMBASE, CENTRAL (The Cochrane Library), ClinicalTrials.gov and the International Clinical Trials Registry Platform (World Health Organization) was carried out to identify all peer-reviewed publications on clinical validation or implementation of maternal cfDNA testing for trisomies 21, 18 and 13 in twin pregnancy, irrespective of gestational age at testing, in which data on pregnancy outcome were provided for at least 85% of the study population. Meta-analysis was performed using the FMF data and data from the studies identified by the literature search. This review was registered in the PROSPERO international database for systematic reviews RESULTS: In the FMF study, cfDNA testing was carried out in 1442 twin pregnancies and a result was obtained, after first or second sampling, in 1367 (94.8%) cases. In 93.1% (1272/1367) of cases, there was prenatal or postnatal karyotyping or birth of phenotypically normal babies; 95 cases were excluded from further analysis either because the pregnancy ended in termination, miscarriage or stillbirth with no known karyotype (n = 56) or there was loss to follow-up (n = 39). In the 1272 pregnancies included in the study, there were 20 cases with trisomy 21, 10 with trisomy 18, two with trisomy 13 and 1240 without trisomy 21, 18 or 13. The cfDNA test classified correctly 19 (95.0%) of the 20 cases of trisomy 21, nine (90.0%) of the 10 cases of trisomy 18, one (50.0%) of the two cases of trisomy 13 and 1235 (99.6%) of the 1240 cases without any of the three trisomies. The literature search identified 12 relevant studies, excluding our papers because their data are included in the current study. In the combined populations of our study and the 12 studies identified by the literature search, there were 137 trisomy-21 and 7507 non-trisomy-21 twin pregnancies; the pooled weighted detection rate (DR) and false-positive rate (FPR) were 99.0% (95% CI, 92.0-99.9%) and 0.02% (95% CI, 0.001-0.43%), respectively. In the combined total of 50 cases of trisomy 18 and 6840 non-trisomy-18 pregnancies, the pooled weighted DR and FPR were 92.8% (95% CI, 77.6-98.0%) and 0.01% (95% CI, 0.00-0.44%), respectively. In the combined total of 11 cases of trisomy 13 and 6290 non-trisomy-13 pregnancies, the pooled weighted DR and FPR were 94.7% (95% CI, 9.14-99.97%) and 0.10% (95% CI, 0.03-0.39%), respectively.

CONCLUSIONS

In twin pregnancy, the reported DR of trisomy 21 by cfDNA testing is high, but lower than that in singleton pregnancy, whereas the FPR appears to be equally low. The number of cases of trisomy 18 and more so trisomy 13 was too small for accurate assessment of the predictive performance of the cfDNA test. © 2021 International Society of Ultrasound in Obstetrics and Gynecology.

The association between maternal complications and small for gestational age in twin pregnancies using singleton and twin birth weight references

INTRODUCTION

In singleton pregnancies, maternal complications, such as preeclampsia and thyroid dysfunction are associated with small for gestational age (SGA). However, data on the association between SGA and maternal complications in twin pregnancies are limited and conflicting. Small sample size and the application of singleton birth weight reference (SBWR) to define SGA in twins may be reasons for the inconsistent conclusions. Purpose of this study was to define SGA in dichorionic diamniotic (DCDA) and monochorionic diamniotic (MCDA) twin pregnancies using both SBWR and twin birth weight reference (TBWR) and to determine whether certain maternal complications are associated with SGA in twin pregnancies.

MATERIALS AND METHODS

This retrospective cohort study included all twins delivered in a single tertiary center between 2013 and 2018. SGA was defined as a twin with birth weight <10th centile for gestational age using either SBWR or TBWR. The association between SGA and maternal complications was analyzed separately for DCDA and MCDA twin pregnancies, expressed as odds ratio (OR) and adjusted odds ratio (aOR) with 95% confidence interval (95%-CI).

RESULTS

A total of 2005 DCDA and 467 MCDA twin pregnancies were enrolled. In DCDA pregnancies, SGA was significantly associated with PE according to TBWR (22.73 vs. 14.56%, aOR 1.823, 95%-CI 1.137-2.922). This association was even more pronounced between SGA and severe PE (9.09 vs. 4.54%, aOR 2.234, 95%-CI 1.115-4.479). In turn, PE was associated with higher risk of SGA defined according to TBWR (8.31 vs. 4.99%, aOR 1.825, 95%-CI 1.139-2.925). No association was detected between SGA and other maternal complications. Using SBWR, no association was found between preeclampsia and SGA. In MCDA pregnancies, according to TBWR, SGA was associated only with severe PE (12.5 vs. 4.06%, aOR 3.470, 95%-CI 1.256-9.587) and lower risk of PROM (aOR 0.067, 95%-CI 0.014-0.322).

CONCLUSION

PE was associated with SGA in DCDA pregnancies only when TBWR was used, suggesting that DCDA pregnancies complicated with PE should be closely monitored for signs of SGA and vice versa. In MCDA pregnancies, SGA defined according to TBWR was associated with only severe PE (but not with all PE) and lower risk of PROM. More basic experiments are needed to investigate the mechanisms underlying PE and SGA in DCDA and MCDA twin pregnancies respectively.

The association of hypertensive disorders of pregnancy with small for gestational age and intertwin birthweight discordance

Available evidence shows conflicting results regarding the association between hypertensive disorders of pregnancy (HDPs)/preeclampsia (PE) and small for gestational age (SGA) and birthweight discordance (BWD). This retrospective study of 2131 twin pregnancies aimed to evaluate the association of HDPs/PE with the presence of SGA and BWD. The eligible pregnancies were categorized into four study groups: concordant pairs without SGA fetuses, discordant pairs without SGA fetuses, concordant pairs with SGA fetuses, and discordant pairs with SGA fetuses. We applied binary logistic regression models to compare the incidence of HDPs/PE and multinomial logit regression models to evaluate the severity of PE between the study groups. The models were adjusted for potential confounders. Increases in HDPs were observed in concordant (aOR, 2.33; 95% CI: 1.46-3.73) and discordant (aOR, 3.50; 95% CI: 2.26-5.43) pregnancies with SGA fetuses but not in discordant pregnancies without SGA fetuses (aOR, 1.42; 95% CI: 0.81-2.49); increases in PE were also found in concordant (aOR, 1.87; 95% CI: 1.08-3.23) and discordant (aOR, 3.75; 95% CI: 2.36-5.96) pregnancies with SGA fetuses but not in discordant pregnancies without SGA fetuses (aOR, 1.34; 95% CI: 0.71-2.52). Discordant pregnancies with SGA fetuses were associated with severe PE (aRRR, 3.48; 95% CI: 1.79-6.77), whereas concordant pregnancies with SGA fetuses were associated with only mild PE (aRRR, 2.54; 95% CI: 1.33-4.88). Our results suggest that SGA is associated with the development of HDP/PE, while discordant growth is associated with the severity of PE. These associations need to be further investigated using estimated fetal weight (EFW).

The influence of hypertensive disorders during pregnancy on the perinatal outcome of different chorionic twins

OBJECTIVE

To investigate the influence of hypertensive disorders of pregnancy (HDP) on the perinatal outcomes in twin pregnancies.

METHODS

This was a retrospective single-center study in which, 2160 twin pregnancies delivered between January 2016 and December 2019 were analyzed, 1661 of which were dichorionic (DC) and 499 monochorionic (MC). The perinatal outcomes were compared in 404 twin pregnancies with HDP, including 157 gestational hypertension (GH), 107 mild pre-eclampsia (MPE), 140 severe pre-eclampsia (SPE), and 1756 twins without hypertensive disorders of pregnancy (no-HDP). Multiple linear regression was performed to analyze the association between perinatal outcome and HDP. Stratified sampling by twin chorionicity (DC and MC) was also conducted.

RESULTS

There were 330 (19.9%) DC cases complicated with HDP and 74 (14.8%) MC with HDP, and the difference between the two groups was statistically significant (p=.011). After stratification by chorionicity, in the DC twin, there were significantly more deliveries in the GH group, MPE group, and SPE group before 37 weeks than in the no-HDP group (p=.000). Statistically significant differences were found among the four groups in the average small fetus birthweight, the intertwin weight difference, the relative weight discordance, the growth discordance, the incidence of very low birth weight (VLBW), low birth weight (LBW), and the Apgar scores of the small fetus (p<.05). In MC twins, By comparison only on the average gestational age at delivery, the average small fetus birthweight, Apgar scores of large and small fetuses among the four groups, the difference was statistically significant (p<.05). According to multiple linear regression analysis, after controlling for multiple confounding factors, it was found when the degree of HDP in DC twins increased by one grade, the small fetus birthweight decreased by an average of 19.044 g (p=.007), the intertwin weight difference increased by an average of 14.311 g (p=.034), the relative weight discordance increased by an average of 0.6% (p=.013), and the gestational age at delivery decreased by an average of 0.160 weeks (p=.001).

CONCLUSIONS

The perinatal outcomes of different chorionic twins with HDP are different. HDP has a greater impact on the perinatal outcomes of DC twins. The risk of adverse perinatal outcomes in DC twin pregnancy will increase accordingly with each increase in the grade of HDP, but HDP has little or no relevance on the perinatal outcomes of MC twins.

Pregnancy and neonatal outcomes of twin pregnancies - the role of maternal age

OBJECTIVES

We aim to study the association of maternal age with maternal and neonatal complications in twin pregnancies.

METHODS

A retrospective cohort study of dichorionic-diamniotic twin pregnancies stratified into three groups according to maternal age ("A" <25, "B" 25-34 and "C" 35-44 years old). Outcome measures included pregnancy, delivery and neonatal complications. A sub-analysis of in vitro fertilization pregnancies only was conducted.

RESULTS

Compared with younger women (groups A [n=65] and B [n=783]), older women [group C (n=392)] demonstrated significantly higher rates of gestational diabetes mellitus (B 6.6% vs. A 0%, p =0.027, C 10.2% vs. B 6.6%, p =0.032), were more likely to undergo cesarean deliveries (C 66.6%, B 57.6%, A 52.3%, p =0.007), and were at increased risk of having more than 20% difference in weight between the twins (C 24.5%, B 17.4%, A 16.9%, p =0.013). Other outcomes, including preeclampsia, did not differ between the groups. A sub-analysis of the in vitro fertilization only pregnancies was performed. Compared with younger women (groups A [n=18] and B [n=388]), older women (group C [n=230]) underwent more cesarean deliveries (p=0.004), and had more than 20% difference in weight between the twins (p<0.004). Other outcomes, including gestational diabetes mellitus rates and preeclampsia, did not differ between the groups.

CONCLUSIONS

Women at advanced maternal age with dichorionic twin pregnancies had significantly higher rates of gestational diabetes mellitus, cesarean deliveries and fetal weight discordancy as compared with younger women. In contrast, the incidence of preeclampsia was not affected by maternal age.