Twins versus singletons-Long-term health outcomes

Long-term gastrointestinal morbidity among twins conceived by assisted reproductive technology

BACKGROUND

Assisted reproductive technologies (ART) increased the incidence of multiple pregnancies, which has a negative effect on offspring health outcomes. The long-term health outcomes for singletons born after ART is well studied, however, studies on ART twin's long-term morbidities are scarce.

OBJECTIVE

This study aimed to investigate a possible association between ART resulting in twin pregnancy and long-term gastrointestinal (GI) morbidity of the offspring.

STUDY DESIGN

A population-based cohort study was performed in a tertiary medical center including twin deliveries born between 1991-2021. Long-term GI morbidities among twins conceived via ART including ovulation induction (OI) and in-vitro fertilization (IVF) were compared with twins born following spontaneous pregnancies. The diagnoses of GI morbidities were defined based on ICD-9 codes as recorded in community clinics and hospitalization files. A Kaplan-Meier survival curve was used to compare the cumulative incidence of GI morbidity among the study group and a Cox proportional hazards model was constructed to control for possible confounders.

RESULTS

A total of 7,790 twins met the inclusion criteria: 2,076 twins (26.6 %) were conceived by ART. The total GI morbidity rate was significantly higher in twins conceived by ART as compared with twins from spontaneous pregnancies (34.9 % for IVF, 34.3 % for OI and 27.0 % for spontaneous twins, p < 0.001). In addition, the cumulative incidence of GI morbidity over time was elevated for twins conceived by ART (log-rank test, p < 0.001). The Cox model, controlling for confounders such as maternal age, gestational age, hypertensive disorders and diabetes mellitus found that using ART resulting in twin pregnancy is an independent risk factor for long-term GI morbidity of twin offspring (adjusted hazards ratio (aHR) for IVF vs. spontaneous = 1.42 (95 %CI 1.27-1.58, p < 0.001; aHR for OI vs spontaneous = 1.38 (95 %CI 1.20-1.60, p < 0.001).

CONCLUSION

In our cohort, twins conceived by ART exhibited a higher risk for long-term GI morbidity compared with spontaneously conceived twins. This association remained after adjustment for confounders although part of the increased risk may be mediated by perinatal complications such as prematurity and cesarean delivery.

Antipsychotic Discontinuation and Re-initiation in Pregnant Women With Schizophrenia: A Retrospective Cohort Study From South Korea

BACKGROUND AND HYPOTHESIS

Pregnant women with schizophrenia are more likely to discontinue treatment, which could trigger a relapse of symptoms. However, data on patterns and risk factors related to antipsychotic discontinuation and re-initiation in Asian pregnant women are insufficient.

STUDY DESIGN

We conducted a retrospective cohort study using a nationwide Korean database. The pregnancy group included women who had received antipsychotics before pregnancy and was matched 1:2 with a non-pregnancy group. Using Kaplan-Meier curves, we assessed discontinuation patterns during pregnancy and re-initiation patterns among those who discontinued treatment within the first trimester. A Cox proportional hazards regression analysis was used to examine factors associated with first-trimester discontinuation and re-initiation among those who discontinued during this period.

STUDY RESULTS

Pregnant women (n = 2066) had a significantly higher risk of discontinuation than did non-pregnant women (adjusted hazard ratio 3.09; 95% confidence interval 2.85-3.34). Within the first trimester, 67.5% of pregnant women (n = 1394) discontinued antipsychotic use. Women aged 25-29 years were more likely to discontinue (1.25; 1.07-1.47). Among first-trimester discontinuers, 35.2% (n = 491) re-initiated treatment before delivery. A longer duration of antipsychotic use (1.60; 1.06-2.42) and higher daily doses (2.47; 1.76-3.45) were associated with re-initiation of antipsychotics.

CONCLUSIONS

We revealed that most pregnant women discontinued schizophrenia treatment, but those using higher cumulative doses had a higher likelihood of re-initiation. Our findings imply that treatment decisions for pregnant women should consider various clinical factors, including the history of prescriptions and obstetric characteristics. Moreover, these patients require close monitoring after discontinuation.

Amniocentesis and Risk of Fetal Loss in Dichorionic-Diamniotic Twin Pregnancy: A Case-Control Study

OBJECTIVE

There is a paucity of data regarding the risk of fetal loss due to invasive prenatal diagnosis in twins. The aim of the present study is to assess the rate of amniocentesis-related fetal loss in uncomplicated dichorionic-diamniotic (DCDA) twin pregnancies.

METHODS

Retrospective observational case-control study. DCDA twin pregnancies undergoing amniocentesis between January 2010 and December 2023 formed the case group. The control group comprised counterparts who did not undergo amniocentesis. The primary outcome of the study was procedure-related fetal loss. Secondary outcomes were miscarriage rate, overall fetal loss and gestational age at birth.

RESULTS

Our dataset included 220 and 662 women in the case and control groups, respectively. No difference in the primary outcome was found: procedure-related fetal loss of one fetus was 0.9% in the case group and 1.1% in the control group, and of both fetuses it was 0.5% in both groups (p = 0.982). No difference was found in secondary outcomes: the fetal loss rate of one fetus was 1.8% in the case group and 2.1% in the control group, while that of both fetuses it was 0.5% and 0.8% respectively (p = 0.853). Multivariate analysis confirmed the nonsignificant effect of amniocentesis on the risk of fetal loss.

CONCLUSION

Amniocentesis does not seem to increase the risk of fetal loss in uncomplicated DCDA twin pregnancies above the baseline risk of loss among twin gestations.

First-trimester screening and small for gestational age in twin pregnancies: a single center cohort study

OBJECTIVE

This study aimed to investigate the association between maternal factors and first-trimester biophysical and biochemical markers with small for gestational age (SGA) neonates in twin pregnancies (TwPs).

METHODS

Single-center retrospective cohort study of TwPs followed from January 2010 to December 2022 at a tertiary perinatal center, Portugal. Maternal and pregnancy characteristics, mean arterial pressure, pregnancy-associated plasma protein-A (PAPP-A), β-human chorionic gonadotropin (β-HCG), and uterine artery pulsatility index (UtA-PI) were analyzed. Univariable, multivariable logistic regression (LR) and receiver-operating characteristic curve analyses were performed. The main outcome measures considered were: SGA < 3rd, < 5th and < 10th percentile, the composite outcome of SGA combined with preterm birth (PTB) (< 32, < 34, and < 36 weeks).

RESULTS

572 TwPs were included, 450 (78.7%) DC and 122 (21.3%) MC. TwPs affected with SGA < 3rd, < 5th or < 10th percentiles were 120/572 (20.9%), 157/572 (27.4%) and 190/572 (33.2%), respectively. SGA < 3rd percentile was associated with a higher rate of PTB, 59.0% of cases < 32 weeks, OR 6.4 (95% CI: 3.2-12.7, p < 0.001). Shorter maternal height, UtA-PI ≥ 95th percentile, and low PAPP-A were identified as significant independent risk factors associated with SGA and SGA combined with PTB. The best LR model was obtained for the composite outcome SGA < 3rd percentile and PTB < 32 weeks, with an AUC of 0.834, a sensitivity rate of 77%, and a false positive rate of 17%.

CONCLUSION

The majority of pregnancies at risk for SGA combined with prematurity can be detected in the first trimester. However, larger datasets are necessary to develop robust predictive models.

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.

Placental abruption and perinatal mortality in twins: novel insight into management at preterm versus term gestations

Twins suffer a disproportionately higher burden of adverse perinatal outcomes than singletons. However, the degree to which preterm delivery shapes the relationship between abruption and perinatal mortality in twins is unknown. Through causal mediation decomposition, we examine how preterm delivery mediates the effect of abruption on perinatal mortality among twins using the US-matched multiple birth data (1995-2000). We estimated the hazard ratio (HR) from Cox models with gestational age as the timescale. We decomposed the total effect (TE) into counterfactual natural direct (NDE) and natural indirect (NIE) effects. 557,220 matched twin births, 1.3% (n = 7032) resulted in abruption with higher perinatal mortality rates than non-abruption births (143 versus 36 per 1000 births, respectively) and a 4.53-fold (95% confidence interval [CI]: 4.23, 4.82) increased hazard of perinatal mortality. HRs for NDE and NIE were 3.05 (95% CI: 2.84, 3.24) and 1.49 (95% CI: 1.49, 1.47, 1.50), respectively, and the proportion mediated (PM) was 41%. PM increased as the gestational age at delivery decreased. Associations persisted after correction for unmeasured confounders. The best strategies to improve perinatal delivery are delivery when abruption complicates twin pregnancies at term gestations and expectant management (avoiding early preterm delivery), if feasible, when abruption complicates twin pregnancies at preterm gestations.

Prevention of preterm birth in twin-to-twin transfusion syndrome: a systematic review and network meta-analysis

OBJECTIVES

We aimed to perform a systematic review and network meta-analysis to evaluate the preventive strategies for preterm birth in twin-to-twin transfusion syndrome.

METHODS

PubMed, Embase and Cochrane Central were searched from inception to December 2023 with no filters. Additionally, the reference lists of the included studies were manually examined to identify any supplementary studies. We selected randomized controlled trials and cohorts comparing interventions to prevent preterm birth in twin pregnancies complicated by twin-to-twin transfusion syndrome. A random-effects frequentist network meta-analysis was performed using RStudio version 4.3.1. Randomized controlled trials and cohorts were assessed respectively using the Risk of Bias in Non-randomized Studies of interventions tool and Cochrane Collaboration's tool for assessing risk of bias in randomized trials.

RESULTS

In this systematic review and meta-analysis, we included eight studies comprising a total of 719 patients. Compared with expectant management, cerclage stood out as the only intervention associated with an increase in the survival of at least one twin (risk ratio 1.12; 95 % confidence interval 1.01-1.23). Our subgroup analysis based on different thresholds for short cervix demonstrated a significant reduction in the risk of preterm birth before 32 weeks with ultrasound-indicated cerclage using a 15 mm criterion (risk ratio 0.65; 95 % confidence interval 0.47-0.92).

CONCLUSIONS

Our study suggests the potential benefit of cerclage as a preventive strategy for preterm birth in pregnancies complicated by twin-to-twin transfusion syndrome. These findings highlight the necessity for further investigation to corroborate our results and address the optimal threshold for ultrasound-indicated cerclage.

The effect of perceived social support on fatigue in mothers having twin infants: the mediating role of sleep quality

The aim of this study is to investigate the mediating role of sleep quality in the relationship between multidimensional perceived social support and fatigue among mothers of twin infants. One hundred and six (106) twin mothers participated in this cross-sectional study, who completed the Descriptive Information Form, Multidimensional Scale of Perceived Social Support, Pittsburgh Sleep Quality Index, and Checklist Individual Strength. The scale score averages of the mothers in the study are as follows: social support, 61.41 ± 23.86; fatigue, 77.64 ± 28.68; and sleep quality, 8.26 ± 2.38. According to the path model, perceived social support has a negative effect on poor sleep quality (p = .001, Beta = -0.411), and poor sleep quality has a positive effect on fatigue (p = .001, Beta = 0.335). Sleep quality also mediates the effect of multidimensional perceived social support on mothers' fatigue levels (p = .001, Beta = -0.138). The study results suggest that the perceived social support and fatigue levels of twin mothers are moderate, while their sleep quality is poor. Therefore, mothers of twin infants may benefit from increased social support to alleviate fatigue and enhance sleep quality.

First-trimester serum biomarkers in twin pregnancies and adverse obstetric outcomes-a single center cohort study

PURPOSE

This study aimed to determine the association of first-trimester maternal serum biomarkers with preterm birth (PTB), fetal growth restriction (FGR) and hypertensive disorders of pregnancy (HDP) in twin pregnancies.

METHODS

This is a retrospective cohort study of twin pregnancies followed at Maternidade Dr. Alfredo da Costa, Lisbon, Portugal, between January 2010 and December 2022. We included women who completed first-trimester screening in our unit and had ongoing pregnancies with two live fetuses, and delivered after 24 weeks. Maternal characteristics, pregnancy-associated plasma protein-A (PAPP-A) and β-human chorionic gonadotropin (β-hCG) levels were analyzed for different outcomes: small for gestational age (SGA), gestational hypertension (GH), early and late-onset pre-eclampsia (PE), as well as the composite outcome of PTB associated with FGR and/or HDP. Univariable, multivariable logistic regression analyses and receiver-operating characteristic curve were used.

RESULTS

466 twin pregnancies met the inclusion criteria. Overall, 185 (39.7%) pregnancies were affected by SGA < 5th percentile and/or HDP. PAPP-A demonstrated a linear association with gestational age at birth and mean birth weight. PAPP-A proved to be an independent risk factor for SGA and PTB (< 34 and < 36 weeks) related to FGR and/or HDP. None of the women with PAPP-A MoM > 90th percentile developed early-onset PE or PTB < 34 weeks.

CONCLUSION

A high serum PAPP-A (> 90th percentile) ruled out early-onset PE and PTB < 34 weeks. Unless other major risk factors for hypertensive disorders are present, these women should not be considered candidates for aspirin prophylaxis. Nevertheless, close monitoring of all TwP for adverse obstetric outcomes is still recommended.

Association Between Maternal Body Mass Index and Fetal Acidosis in Term Twin Pregnancies: A Retrospective Cohort Study

OBJECTIVES

Given the increased risk of fetal acidosis in singleton neonates born to pregnant people with an elevated BMI, our objective was to evaluate the association between pre-pregnancy/first-trimester BMI and fetal acidosis among term twin pregnancies.

METHODS

Retrospective study of pregnant people with twin gestation and their term infants admitted to our centre between 2014 and 2019. Using a generalized estimating equation, the association between maternal BMI and fetal acidosis was determined using odds ratios (ORs) with 95% CIs. A two-sided P < 0.05 was considered significant.

RESULTS

A total of 275 pregnant people and 550 infants were analyzed. The number (%) of pregnancies in each BMI class were 10 (4%) underweight, 155 (56%) normal weight, 66 (24%) overweight, 22 (8%) class I, 9 (3%) class II, and 13 (5%) class III. The prevalence of maternal diabetes and hypertension was highest in class III (31%) and class II (44%), respectively. Fetal acidosis was diagnosed in 35 (6%) infants. After adjusting for confounders (maternal age, diabetes, and hypertension), infants born to those with elevated BMI did not have increased odds of fetal acidosis compared to those born to underweight and normal weight group (OR 1.29; 95% CI 0.38-4.41 for class I, P = 0.67 and OR 2.80; 95% CI 0.62-12.62 for the combined classes II and III, P = 0.18).

CONCLUSIONS

Maternal BMI was not associated with fetal acidosis in term twin pregnancies. Further research is required to corroborate study findings due to small sample size.

Abnormal cleavage up to Day 3 does not compromise live birth and neonatal outcomes of embryos that have achieved full blastulation: a retrospective cohort study

STUDY QUESTION

Do embryos displaying abnormal cleavage (ABNCL) up to Day 3 have compromised live birth rates and neonatal outcomes if full blastulation has been achieved prior to transfer?

SUMMARY ANSWER

ABNCL is associated with reduced full blastulation rates but does not impact live birth rates and neonatal outcomes once full blastulation has been achieved.

WHAT IS KNOWN ALREADY?

It is widely accepted that ABNCL is associated with reduced implantation rates of embryos when transferred at the cleavage stage. However, evidence is scarce in the literature reporting birth outcomes from blastocysts arising from ABNCL embryos, likely because they are ranked low priority for transfer.

STUDY DESIGN, SIZE, DURATION

This retrospective cohort study included 1562 consecutive autologous in vitro fertilization cycles (maternal age 35.1 ± 4.7 years) performed at Fertility North, Australia between January 2017 and June 2022. Fresh transfers were performed on Day 3 or 5, with remaining embryos cultured up to Day 6 before vitrification. A total of 6019 embryos were subject to blastocyst culture, and a subset of 664 resulting frozen blastocysts was included for live birth and neonatal outcome analyses following single transfers.

PARTICIPANTS/MATERIALS, SETTING, METHODS

ABNCL events were annotated from the first mitotic division up to Day 3, including direct cleavage (DC), reverse cleavage (RC) and <6 intercellular contact points at the 4-cell stage (<6ICCP). For DC and RC in combination, the ratios of affected blastomeres over the total number of all blastomeres up to Day 3 were also recorded. All pregnancies were followed up until birth with gestational age, birthweight, and sex of the baby being recorded.

MAIN RESULTS AND THE ROLE OF CHANCE

Full blastulation rates for embryos showing DC (19.5%), RC (41.7%), <6ICCP (58.8%), and mixed (≥2) ABNCL types (26.4%) were lower than the rates for those without ABNCL (67.2%, P < 0.01 respectively). Subgroup analysis showed declining full blastulation rates with increasing ratios of combined DC/RC affected blastomeres over all blastomeres up to the 8-cell stage (66.2% when 0 affected, 47.0% when 0.25 affected, 27.4% when 0.5 affected, 14.5% when 0.75 affected, and 7.7% when all affected, P < 0.01). However, once full blastulation had been achieved, no difference was detected between DC, RC, <6ICCP, and no ABNCL blastocysts following single frozen transfers in subsequent live birth rates (25.9%, 33.0%, 36.0% versus 30.8%, P > 0.05, respectively), gestational age (38.7 ± 1.6, 38.5 ± 1.2, 38.3 ± 3.5 versus 38.5 ± 1.8 weeks, P > 0.05, respectively) and birthweight (3343.0 ± 649.1, 3378.2 ± 538.4, 3352.6 ± 841.3 versus 3313.9 ± 509.6 g, P > 0.05, respectively). Multiple regression (logistic or linear as appropriate) confirmed no differences in all of the above measures after accounting for potential confounders.

LIMITATIONS, REASONS FOR CAUTION

Our study is limited by its retrospective nature, making it impossible to control every known or unknown confounder. Embryos in our dataset, being surplus after selection for fresh transfer, may not represent the general embryo population.

WIDER IMPLICATIONS OF THE FINDINGS

Our findings highlight the incremental impact of ABNCL, depending on the ratio of affected blastomeres up to Day 3, on subsequent full blastulation. The reassuring live birth and neonatal outcomes of ABNCL blastocysts imply a potential self-correction mechanism among those embryos reaching the blastocyst stage, which provides valuable guidance for clinical practice and patient counseling.

STUDY FUNDING/COMPETTING INTEREST(S)

This research is supported by an Australian Government Research Training Program (RTP) Scholarship. All authors report no conflict of interest.

TRIAL REGISTRATION NUMBER

N/A.

Is the Early Screening of Lower Genital Tract Infections Useful in Preventing Adverse Obstetrical Outcomes in Twin Pregnancy?

Objectives: Twin pregnancy implies a higher risk of preterm birth and, consequently, higher neonatal morbidity and mortality. In singleton pregnancies, infections of the lower genital tract (LGTIs) and bacterial vaginosis are associated with preterm labor, and their early detection has been proven effective in reducing complications like the preterm premature rupture of membranes (pPROM) and preterm delivery. The same evidence, however, is lacking for twin pregnancies. This study aimed to evaluate whether the early identification and treatment of LGTIs or bacterial vaginosis in asymptomatic women with twin pregnancy could reduce the rate of miscarriages, pPROM, and preterm birth. Methods: This study performed a retrospective comparison of 285 women with a multiple pregnancy submitted for a cervico-vaginal swab only at 20-22 weeks (Single Test Group, STG), and 199 women who underwent the swab at 12-14 and again at 20-22 weeks (Double Test Group, DTG). All women included in the study had a twin pregnancy and were followed up at Sant'Anna Hospital, Turin (Italy), between September 2012 and February 2021. Results: In STG, 21.7% of patients had a positive swab; in DTG, 19.9% had an early positive swab that was immediately treated by targeted antibiotics; and 16.7% had a mid-pregnancy positive swab. The DTG showed a significantly lower incidence of pPROM in univariate analysis (14.4% vs. 23.1%, p = 0.021), which was confirmed by multivariate analysis (OR 0.55, CI 0.33-0.93, p = 0.025). Conclusions: Our study suggests that, in asymptomatic women with twin pregnancy, the early screening of LGTIs and bacterial vaginosis by a cervico-vaginal swab at 12-14 weeks of gestational age is effective in reducing the risk of pPROM.