Prediction of preterm birth in twin gestations using biophysical and biochemical tests

Knowledge mapping for prediction of spontaneous preterm birth

INTRODUCTION

Preterm birth (PTB) before 37 weeks gestation, especially spontaneous premature birth (sPTB), poses significant global health challenges, with rising rates linked to advanced and multiple pregnancies. Despite efforts to understand the pathogenesis and related biomarkers of sPTB, accurate prediction is still difficult to achieve. Recent research in academic journals has focused on sPTB prediction, prompting our bibliometric analysis to understand the current situation and explore the new research direction.

METHODS

We used keywords in the Web of Science Core Collection (WoSCC) to search for articles related to sPTB prediction from 2004 to 2023. Subsequently, we primarily employed three distinct software tools (VOSviewer, CiteSpace, and Python) for conducting this bibliometric analysis.

RESULTS

Focusing on sPTB as the primary subject, a total of 647 papers have been published in 136 academic journals. There are the most publications from The United States (n = 245, 39.26 %), and the University of London contributed the most publications (n = 57, 8.81 %). The American Journal of Obstetrics and Gynecology is the most productive academic journal on sPTB prediction [n = 74, 11.44 %; impact factor (IF) = 8.7]. Through the co-occurrence and cluster analysis, we found that recent research has focused on is "pamg-1", "uterocervical angle", "twin pregnancy", "quantitative ultrasound", and "lactobacillus iners".

CONCLUSION

We utilized bibliometric software to perform a comprehensive analysis of the literature concerning sPTB prediction. Broadly, the primary focus of future sPTB prediction lies in the application of novel ultrasound and biological markers, as well as in predicting sPTB in twin pregnancies.

The clinic application of mNGS and ENA-78 assays to identify intra-amniotic infection/inflammation

Objective

The objective of this study is to explore whether metagenomic next-generation sequencing (mNGS) and Epithelial Neutrophil Activating Peptide-78 (ENA-78) assays in the amniotic fluid (AF) of patients with preterm labor (PTL) could be employed for diagnosing intra-amniotic infection/inflammation (IAI/I) and predict the outcomes of emergency cerclage in women with cervical insufficiency(CI).

Methods

AF samples from 40 patients were subjected to PTL were subjected to mNGS and microbial culture to diagnose intra-amniotic infection known as microbial invasion of the amniotic cavity (MIAC); ELISA was used to analyze ENA-78 levels for prediction of intra-amniotic inflammation (IAI). Pregnancy outcomes were compared, the predictive performance of mNGS and ENA-78 were assessed to evaluate the efficacy of emergency cervical cerclage.

Results

The diagnosis rate of MIAC was higher with mNGS (17.5%) compared to microbial culture (2.5%). AF ENA-78 levels were significantly higher in IAI patients than in non-IAI/I patients. ENA-78 demonstrated certain accuracy in identifying IAI, with sensitivity and specificity of 73.3% and 100%, respectively. Compared with non-IAI/I patients, patients with MIAC or IAI exhibited poor pregnancy outcomes after cervical cerclage.

Conclusions

mNGS and ENA-78 assays are valuable means for assessing the state of infection/inflammation in the amniotic cavity and predicting the outcomes of emergency cerclage.

Counselling in Fetal Medicine: Uncomplicated Twin Pregnancies

Twin pregnancies account for 3% of all pregnancies and they are burdened by higher morbidity and mortality compared to singletons. The role of ultrasound in the screening, diagnosis and management of possible complications of twin pregnancies has been widely investigated in the current literature. However, despite the progress that have been made in the last decades regarding treatment and evidence-based management of complications, twin pregnancies remain at higher risk of adverse outcomes, requiring therefore dedicated surveillance. Thorough counselling regarding the risks and prenatal care should be offered to all future parents of twin pregnancies. This review aims to summarize the current evidence regarding the management of uncomplicated dichorionic and monochorionic pregnancies.

Low PAPPA and Its Association with Adverse Pregnancy Outcomes in Twin Pregnancies: A Systematic Review of the Literature and Meta-Analysis

Background: It is well established in the literature that pregnancy-associated plasma protein-A (PAPP-A) is linked to several adverse pregnancy outcomes, including pre-eclampsia (PE), fetal growth restriction (FGR), and preterm birth (PTB) in singleton pregnancies. However, data regarding such an association in twin pregnancies are lacking. The primary goal of this systematic review and meta-analysis was to assess the potential value of low PAPP-A levels in the prediction of the subsequent development of hypertensive disorders of pregnancy (HDPs), PTB, and small for gestational age (SGA)/FGR fetuses in twin pregnancies and investigate its association with the development of gestational diabetes, intrauterine death (IUD) of at least one twin, and birth weight discordance (BWD) among the fetuses. Methods: Medline, Scopus, CENTRAL, Clinicaltrials.gov, and Google Scholar databases were systematically searched from inception until 31 July 2024. All observational studies reporting low PAPP-A levels after the performance of the first-trimester combined test as part of the screening for chromosomal abnormalities with reported adverse pregnancy outcomes were included. Results: The current systematic review encompassed a total of 11 studies (among which 6 were included in the current meta-analysis) that enrolled a total of 3741 patients. Low PAPP-A levels were not associated with HDPs (OR 1.25, 95% CI 0.78, 2.02, I-square test: 13%). Low PAPP-A levels were positively associated with both the development of preterm birth prior to 32 (OR 2.85, 95% CI 1.70, 4.77, I-square test: 0%) and 34 weeks of gestational age (OR 2.09, 95% CI 1.34, 3.28, I-square test: 0%). Furthermore, low PAPP-A levels were positively associated with SGA/FGR (OR 1.58, 95% CI 1.04, 2.41, I-square test: 0%). Prediction intervals indicated that the sample size that was used did not suffice to support these findings in future studies. Conclusions: Our study indicated that low PAPP-A levels are correlated with an increased incidence of adverse perinatal outcomes in twin pregnancies. Identifying women at elevated risk for such adversities in twin pregnancies may facilitate appropriate management and potential interventions, but additional studies are required to identify the underlying mechanism linking PAPP-A with those obstetrical complications.

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.

Development and validation of a prediction model on spontaneous preterm birth in twin pregnancy: a retrospective cohort study

BACKGROUND

This study was conducted to develop and validate an individualized prediction model for spontaneous preterm birth (sPTB) in twin pregnancies.

METHODS

This a retrospective cohort study included 3845 patients who gave birth at the Chongqing Maternal and Child Health Hospital from January 2017 to December 2022. Both univariable and multivariable logistic regression analyses were performed to find factors associated with sPTB. The associations were estimated using the odds ratio (OR) and the 95% confidence interval (CI). Model performance was estimated using sensitivity, specificity, accuracy, area under the receiver operating characteristic curve (AUC) and decision curve analysis (DCA).

RESULTS

A total of 1313 and 564 cases were included in the training and testing sets, respectively. In the training set, univariate and multivariate logistic regression analysis indicated that age ≥ 35 years (OR, 2.28; 95% CI 1.67-3.13), pre-pregnancy underweight (OR, 2.36; 95% CI 1.60-3.47), pre-pregnancy overweight (OR, 1.67; 95% CI 1.09-2.56), and obesity (OR, 10.45; 95% CI, 3.91-27.87), nulliparity (OR, 0.58; 95% CI 0.41-0.82), pre-pregnancy diabetes (OR, 5.81; 95% CI 3.24-10.39), pre-pregnancy hypertension (OR, 2.79; 95% CI 1.44-5.41), and cervical incompetence (OR, 5.12; 95% CI 3.08-8.48) are independent risk factors for sPTB in twin pregnancies. The AUC of the training and validation set was 0.71 (95% CI 0.68-0.74) and 0.68 (95% CI 0.64-0.73), respectively. And then we integrated those risk factors to construct the nomogram.

CONCLUSIONS

The nomogram developed for predicting the risk of sPTB in pregnant women with twins demonstrated good performance. The prediction nomogram serves as a practical tool by including all necessary predictors that are readily accessible to practitioners.

Value of post-cerclage transvaginal ultrasound in predicting preterm birth at <28 weeks in twin pregnancy with ultrasound-indicated cerclage

OBJECTIVE

To evaluate the value of transvaginal ultrasound parameters before and after cerclage in twins in predicting spontaneous preterm birth (sPTB) before 28+0 weeks.

METHODS

We retrospectively studied the medical records of twin-pregnant women who underwent ultrasound-indicated cerclage between January 2016 and February 2022 at our hospital. Recorded transvaginal ultrasound images before and after cerclage were reassessed for cervical length (CL), uterocervical angle (UCA), funneling, and sludge. Multivariate logistic and Cox regression analyses were performed to identify the independent risk factors associated with sPTB before 28 weeks.

RESULTS

A total of 69 women were included. Among them, 17 women (24.64%) delivered before 28 weeks of age. Regression analysis revealed a significant association of post-cerclage CL, UCA, white blood cell (WBC) count, and gestational age (GA) at cerclage with sPTB before 28 weeks. The area under the curve of these predictors was 0.938 (95% confidence interval, 0.882-0.994; p < .001), with a sensitivity of 88.2%, specificity of 92.3%, positive predictive value of 78.9%, and negative predictive value of 96.0%. Cox analysis showed that post-cerclage UCA was an independent risk factor affecting the cerclage-to-delivery interval (hazard ratios, 1.026; 95% confidence interval (CI), 1.004-1.048; p = .019).

CONCLUSIONS

The combination of post-cerclage CL, UCA, WBC count, and GA at cerclage showed good performance in predicting sPTB at <28 weeks in twin pregnancy. Post-cerclage UCA is also associated with pregnancy latency. We found that post-cerclage cervical ultrasound may be useful to predict preterm birth before 28 weeks in twins who undergo ultrasound-indicated cerclage.

Diagnosis or prognosis? An umbrella review of mid-trimester cervical length and spontaneous preterm birth

BACKGROUND

Cervical length is widely used to assess a woman's risk of spontaneous preterm birth (SPTB).

OBJECTIVES

To summarise and critically appraise the evidence from systematic reviews on the prognostic capacity of transvaginal sonographic cervical length in the second trimester in asymptomatic women with singleton or twin pregnancy.

SEARCH STRATEGY

Searches were performed in Medline, Embase, CINAHL and grey literature from 1 January 1995 to 6 July 2021, including keywords 'cervical length', 'preterm birth', 'obstetric labour, premature', 'review' and others, without language restriction.

SELECTION CRITERIA

We included systematic reviews including women who did not receive treatments to reduce SPTB risk.

DATA COLLECTION AND ANALYSIS

From 2472 articles, 14 systematic reviews were included. Summary statistics were independently extracted by two reviewers, tabulated and analysed descriptively. The ROBIS tool was used to evaluate risk of bias of included systematic reviews.

MAIN RESULTS

Twelve reviews performed meta-analyses: two were reported as systematic reviews of prognostic factor studies, ten used diagnostic test accuracy methodology. Ten systematic reviews were at high or unclear risk of bias. Meta-analyses reported up to 80 combinations of cervical length, gestational age at measurement and definition of preterm birth. Cervical length was consistently associated with SPTB, with a likelihood ratio for a positive test of 1.70-142.

CONCLUSIONS

The ability of cervical length to predict SPTB is a prognostic research question; systematic reviews typically analysed diagnostic test accuracy. Individual participant data meta-analysis using prognostic factor research methods is recommended to better quantify how well transvaginal ultrasonographic cervical length can predict SPTB.

Integrative Review of Cobedding of Infant Twins

OBJECTIVE

To synthesize the evidence on the benefits and risks of cobedding for infant twins and to assess the perceptions and practices of parents and health care workers regarding this practice.

DATA SOURCES

We searched the following databases for articles published between 1997 and 2022: CINAHL, Cochrane, Ovid MEDLINE, PubMed, Scopus, and Google Scholar.

STUDY SELECTION

We included full-text articles published in English in which the authors addressed twin cobedding in hospital or home settings. We reviewed the abstracts of 106 articles and retained 54 for full-text review. Of these, 18 met eligibility criteria and were included in the review.

DATA EXTRACTION

We extracted the following data: author(s), year of publication, setting, purpose, study design, sample characteristics, methodologic details, outcomes and findings, and limitations. We appraised the quality of each study.

DATA SYNTHESIS

In the included articles, researchers identified no differences in apnea, heart rate, or oxygen saturation between cobedded and separately bedded infants. Compared to separately bedded infants, cobedded infants had greater weight gain and synchronization of sleep-wake states. Researchers found benefits for procedural pain relief and recovery after heel lance among cobedded infants. Researchers report that many parents are choosing to cobed their twins, but we found limited qualitative data exploring parents' perceptions or practices. In the included articles, nurses had positive perceptions of twin cobedding. Overall, the quality of evidence was low because of inconsistencies in study methods and small sample sizes that resulted in imprecise results.

CONCLUSION

We found potential benefits and no evidence of harm related to cobedding of twin infants. However, the evidence was insufficient to provide recommendations for practice, and additional research is warranted.

Effects of emergency/nonemergency cervical cerclage on the vaginal microbiome of pregnant women with cervical incompetence

Background

Evaluation of the therapeutic effects of cerclage on preterm birth (PTB) caused by cervical incompetence remains challenging. The vaginal microbiome is associated with preterm births. Thus, this study aimed to analyse the vaginal microbiota of patients with cervical incompetence, explore the relationship between the composition of the vaginal microbiota before cervical cerclage and at term delivery, and assess the effect of cervical cerclage on the vaginal microbiota.

Methods

Patients (n = 30) underwent cerclage performed by the same surgical team. Vaginal swabs were obtained pre-surgery and seven days post-surgery. A gestational age-matched cohort of healthy pregnant women (n = 20) (no particular abnormality during pregnancy, delivery at term) was used as the control group and sampled during a comparable pregnancy. All collected vaginal swabs were analysed by 16S rRNA gene sequencing.

Results

When comparing the healthy control and cervical cerclage groups, the enriched microorganism in the healthy controls was G. Scardovia, and the enriched microorganism of the cerclage was G. Streptococcus. α diversity was significantly increased in patients who received cerclage with preterm delivery compared with those with full-term delivery, and the enriched microorganism was F. Enterococcus. A comparison before and after nonemergency cerclage suggested that the enriched microorganisms were G. Lactobacillus and F. Lactobacillaceae before surgery. After nonemergency cerclage, the enriched microorganisms were F. Enterobacteriaceae and C. Gammaproteobacteria. Vaginal microbiota diversity significantly increased, and the proportion of women with Lactobacillus spp.-depleted microbiomes increased after emergency cerclage. Significant differences in β diversity were found between the groups. Before the emergency cerclage, the enriched microorganisms were G. Lactobacillus, O. Alteromonadales, and P. Firmicutes. After emergency cerclage, the enriched microorganisms were P. Actinobacteria, C. Actinobacteria, P. Proteobacteria, F. Bifidobacteriaceae, O. Bifidobacteriales, G. Gardnerella, and G. Veillonella.

Conclusion

Cerclage (particularly emergency cerclage) may alter the vaginal microbiota by increasing microbiota diversity, decreasing vaginal Lactobacillus abundance, and increasing the abundance of pathogenic bacteria that are not conducive to pregnancy maintenance, thereby affecting surgical efficacy. Therefore, the role of the vaginal microbiome should be considered when developing treatment strategies for pregnant women with cervical incompetence.

Clinical trial registration

https://www.chictr.org.cn, identifier ChiCTR2100046305.

Preterm labor with intact membranes: a simple noninvasive method to identify patients at risk for intra-amniotic infection and/or inflammation

OBJECTIVE

To develop a noninvasive scoring system to identify patients at high risk for intra-amniotic infection and/or inflammation, which would reduce the need for amniocentesis.

METHODS

This prospective cohort study comprised patients admitted with preterm labor and intact membranes (20-34 weeks of gestation) who underwent a transabdominal amniocentesis and for whom concentrations of quantitative cervical fetal fibronectin and of maternal serum C-reactive protein (CRP) were determined. Intra-amniotic infection was defined as a positive amniotic fluid culture for microorganisms. Intra-amniotic inflammation was defined as an amniotic fluid matrix metalloproteinase-8 concentration >23 ng/mL. Multivariate logistic regression analysis was performed to identify intra-amniotic infection/inflammtion with noninvasive parameters that had a significant relationship with univariate analysis. With four parameters identified by multivariate analysis, we generated a noninvasive risk scoring system.

RESULTS

Of the study population consisting of 138 singleton pregnant women, (1) the overall rate of intra-amniotic infection/inflammation was 28.3% (39/138); (2) four parameters were used to develop a noninvasive risk scoring system [i.e. cervical fetal fibronectin concentration (score 0-2), maternal serum CRP concentration (score 0-2), cervical dilatation (score 0-2), and gestational age at presentation (score 0-1)]; the total score ranges from 0 to 7; 3) the area under the curve of the risk score was 0.96 (95% confidence interval (CI), 0.92-0.99), significantly higher than that of each predictor in the identification of intra-amniotic infection/inflammation (p < .001, for all); 4) the risk score with a cutoff of 4 had a sensitivity of 94.9% (37/39), a specificity of 90.9% (90/99), a positive predictive value of 80.4% (37/46), a negative predictive value of 97.8% (90/92), a positive likelihood ratio of 10.4 (95% CI, 5.6-19.5), and a negative likelihood ratio of 0.06 (95% CI, 0.15-0.22) in the identification of intra-amniotic infection/inflammation.

CONCLUSIONS

(1) The combination of four parameters (concentrations of cervical fetal fibronectin and maternal serum CRP, cervical dilatation, and gestational age) was independently associated with intra-amniotic infection and/or inflammation; and (2) the risk scoring system comprised of the combination of 4 noninvasive parameters was sensitive and specific to identify the patients at risk for intra-amniotic infection and/or inflammation.

Guideline No. 428: Management of Dichorionic Twin Pregnancies

OBJECTIVE

To review evidence-based recommendations for the management of dichorionic twin pregnancies.

TARGET POPULATION

Pregnant women with a dichorionic twin pregnancy.

BENEFITS, HARMS, AND COSTS

Implementation of the recommendations in this guideline may improve the management of twin pregnancies and reduce neonatal and maternal morbidity and mortality.

EVIDENCE

Published literature was retrieved through searches of PubMed and the Cochrane Library using appropriate controlled vocabulary (e.g., twin, preterm birth). Results were restricted to systematic reviews, randomized controlled trials, controlled clinical trials, and observational studies. There were no date limits, but results were limited to English- or French-language materials.

VALIDATION METHODS

The content and recommendations were drafted and agreed upon by the principal authors. The Board of the SOGC approved the final draft for publication. The authors rated the quality of evidence and strength of recommendations using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach. See online Appendix A (Tables A1 for definitions and A2 for interpretations of strong and weak recommendations).

INTENDED AUDIENCE

Obstetricians, family physicians, nurses, midwives, maternal-fetal medicine specialists, radiologists, and other health care providers who care for women with twin pregnancies.

SUMMARY STATEMENTS

RECOMMENDATIONS.

Prediction of preterm birth using artificial intelligence: a systematic review

Preterm birth is the leading cause of neonatal death. It is challenging to predict preterm birth. We elucidated the state of artificial intelligence research on the prediction of preterm birth, clarifying the predictive values and accuracy. We performed a systematic review using three databases (PubMed, Web of Science, and Scopus) in August 2020, with keywords as 'artificial intelligence,' 'deep learning,' 'machine learning,' and 'neural network' combined with 'preterm birth'. We included 22 publications between 2010 and 2020. Regarding the predictive values, electrohysterogram images were mostly used, followed by the biological profiles, the metabolic panel in amniotic fluid or maternal blood, and the cervical images on the ultrasound examination. The size of dataset in most studies was hundred cases and too small for learning, although only three studies used the medical database over a hundred thousand cases. The accuracy was better in the studies using the metabolic panel and electrohysterogram images. Impact statementWhat is already known on this subject? Preterm birth is the leading cause of newborn morbidity and mortality. Presently, the prediction of preterm birth in individual cases is still challenging.What the results of this study add? Using artificial intelligence such as deep learning and machine learning models, clinical data could lead to accurate prediction of preterm birth.What the implications are of these findings for clinical practice and/or further research? The size of the datasets was too small for the models using artificial intelligence in the previous studies. Big data should be prepared for the future studies.

Association between antenatal corticosteroids use and perinatal mortality among preterm singletons and twins in Mwanza, Tanzania: an observational study

OBJECTIVES

To examine the association between antenatal corticosteroids (ACS) use and perinatal mortality in singletons and twins delivered before 35 weeks of gestation.

DESIGN

Secondary analysis of data from an observational prospective chart review study that investigated if exposure to ACS was associated with lower rates of perinatal mortality in preterm infants.

SETTING

This study was conducted in four hospitals located in Mwanza region, Tanzania.

PARTICIPANTS

The study population included all preterm singletons and twins delivered at these hospitals between 24 weeks 0 days and 34 weeks 6 days of gestation from July 2019 to February 2020.

OUTCOME MEASURES

The primary outcome was perinatal mortality; the secondary outcome was respiratory distress syndrome (RDS).

RESULTS

The study included 844 singletons and 210 twin infants. Three hundred and fourteen singletons (37.2%) and 52 twins (24.8%) were exposed to at least one dose of ACS. Adjusted multivariate analyses revealed that among singletons' exposure to ACS was significantly associated with a lower likelihood of perinatal mortality, adjusted relative risk (aRR) 0.30 (95% CI 0.22 to 0.40) and RDS, aRR 0.92 (95% CI 0.87 to 0.97). In twin infants, exposure to ACS was associated with a reduced risk of RDS only, aRR 0.87 (95% CI 0.78 to 0.98).

CONCLUSION

The use of ACS between 24 weeks 0 days and 34 weeks 6 days of gestation in both singletons and twins in low-resource settings is associated with positive infant outcomes. No adverse effects were noted. Further research that examines the benefits of ACS for twin infants is needed.

Pregnancy Loss After Amniocentesis with Double-Needle Insertions in Twin Pregnancies

The aim of this study was to determine the pregnancy loss rate of amniocentesis with double-needle insertions in twin pregnancies. This was a retrospective study of twin pregnancies who underwent amniocentesis with double-needle insertion between 2010 and 2019 at a single center. The pregnancy loss rates were recorded as single or double fetal loss before 24 weeks’ gestation and within 4 weeks after the procedure. Risk factors for pregnancy loss after amniocentesis were also assessed. A total of 678 twin pregnancies with amniocentesis were finally included. The pregnancy loss rates before 24 weeks’ gestation and within 4 weeks after the procedure were 0.9% and 1.9%, respectively. Only one fetal loss was presumed to be a direct result of the procedure. All other cases were complicated by structural or chromosomal anomalies. Twin pregnancies with abnormal ultrasound findings had a significantly higher rate of pregnancy loss with a relative risk of 4.81 (95% CI [1.03, 22.2]). Our study showed a low pregnancy loss rate after amniocentesis in twin pregnancies with double-needle insertions technique of sampling, which can help decision making in prenatal screening and diagnosis for twin pregnancies.

Correlation between serum markers in the second trimester and preterm birth before 34 weeks in asymptomatic twin pregnancies

OBJECTIVE

To determine the correlation between the levels of serum markers in the second trimester and preterm birth before 34 weeks in asymptomatic twin pregnancies.

METHODS

We conducted a retrospective review of the medical records of 102 asymptomatic twin pregnancies delivered at Chilgok Kyungpook National University Hospital between March 2014 and February 2020. Participants were divided into two groups, based on delivery before and after 34 weeks of gestation. Results of the quad test performed at 15-18 weeks and the complete blood count done at 24-28 weeks were compared.

RESULTS

Preterm birth before 34 weeks of pregnancy was associated with higher levels of maternal α-fetoprotein (1.04 vs 0.98, multiple of median [MoM], P = 0.006), human chorionic gonadotropin (1.76 vs 1.31, MoM, P = 0.000), and inhibin A (1.78 vs 1.04, MoM, P = 0.000). Positive correlations were observed between gestational age at delivery and white blood cell (WBC) markers. Women with preterm delivery had decreased WBC counts (8180 vs 9405 × 10³ /µl, P = 0.019) and neutrophil:lymphocyte ratios (3.85 vs 4.92, P = 0.001).

CONCLUSION

Serum marker levels in the second trimester can be indicators of preterm delivery before 34 weeks in asymptomatic twin pregnancies.

Self-reported pain scores as a predictor of preterm birth in symptomatic twin pregnancy: a retrospective study

BACKGROUND

To evaluate the self-reported pain scores as a predictor of preterm birth (PTB) in symptomatic twin pregnancy and to develop a nomogram for the prediction model.

METHODS

We conducted a retrospective study of 148 cases of symptomatic twin pregnancies before 34 weeks of gestation visited at Seoul national university hospital from 2013 to 2018. With other clinical factors, self-reported pain score was evaluated by the numerical rating scale (NRS) pain scores for pain intensity. By multivariate analyses and logistic regression, we developed a prediction model for PTB within 7 days. Using the Cox proportional hazards model, the curves were plotted to show the predictability of the PTB according to NRS pain score, while adjusting the other covariates.

RESULTS

Twenty-three patients (15.5 %) delivered preterm within 7 days. By a logistic regression analysis, higher NRS pain score (OR 1.558, 95 % CI 1.093-2.221, P < 0.05), shorter cervical length (OR 3.164, 95 % CI 1.262-7.936, P < 0.05) and positive fibronectin results (OR 8.799, 95 % CI 1.101-70.330, P < 0.05) affect PTB within 7 days. Using the variables, the area under the receiver operating characteristic curve (AUROC) of the prediction model was 0.917. In addition, we developed a nomogram for the prediction of PTB within 7 days.

CONCLUSIONS

Self-reported pain scores combined with cervical length and fetal fibronectin are useful in predicting impending PTB in symptomatic twin pregnancy.

Controversies in the management of twin pregnancy

Despite many advances in antenatal care, twin pregnancies still experience more adverse outcomes, in particular perinatal morbidity and mortality. They also pose a multitude of challenges and controversies, as outlined in this Review. Moreover, they are less likely to be included in clinical trials. Many issues on classification and management remain under debate. Efforts at standardizing diagnostic criteria, monitoring protocols, management and outcome reporting are likely to reduce their perinatal risks. The top 10 most important research uncertainties related to multiple pregnancies have been identified by both clinicians and patients. More robust research in the form of randomized trials and large well-conducted prospective cohort studies is needed to address these controversies. © 2020 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

Perinatal Outcomes and Risk Factors for Preterm Birth in Twin Pregnancies in a Chinese Population: A Multi-center Retrospective Study

Background: Twin pregnancies are associated with an increased risk of adverse maternal and neonatal outcomes, mainly owing to prematurity. Few studies have evaluated the risk factors for preterm birth (PTB) in Chinese population. The objective of this study is to present the short-term maternal-neonatal outcomes, investigating the potential risk factors associated with preterm birth in Chinese twin pregnancies.

Methods: A multi-center retrospective study of women pregnant with twins ≥28 weeks of gestation was conducted. Maternal and neonatal outcomes were analyzed. Logistic regression was used to identify potential risk factors for PTB before 37, 34, and 32 weeks, respectively.

Results: A total of 3,288 twin pregnancies and 6,576 neonates were included in 99,585 pregnancies. The rate of twin pregnancy was 3.3%, while the PTB rate before 37, 34, and 32 weeks among this population were 62.1, 18.8, and 10.4%, respectively. Logistic regression revealed that monochorionicity [Odds ratio (OR) 3.028, 95% confident interval (CI) 2.489–3.683, P < 0.001], gestational weight gain (GWG) <10 kg (OR 2.285, 95% CI 1.563–3.339, P < 0.001) and GWG between 10 and 15 kg (OR 1.478, 95% CI 1.188–1.839, P < 0.001), preeclampsia (PE) (OR 3.067, 95% CI 2.142–4.390, P < 0.001), and intrahepatic cholestasis of pregnancy (ICP) (OR 3.122, 95% CI 2.121–4.596, P < 0.001) were the risk factors for PTB before 37 weeks. Monochorionicity (OR 2.865, 95% CI 2.344–3.501, P < 0.001), age < 25 years (OR 1.888, 95% CI 1.307–2.728, P = 0.001), and GWG <10 kg (OR 3.100, 95% CI 2.198–4.372, P < 0.001) were risk factors for PTB before 34 weeks. Monochorionicity (OR 2.566, 95% CI 1.991–3.307, P < 0.001), age younger than 25 years (OR 1.964, 95% CI 1.265–3.048, P = 0.003), and GWG <10 kg (OR 4.319, 95% CI 2.931–6.364, P < 0.001) were the risk factors for PTB before 32 weeks.

Conclusions: Monochorionicity and GWG <10 kg were two major risk factors for PTB before 32, 34, and 37 weeks, whereas maternal age, PE, and ICP were also risk factors for PTB in specific gestational age.

Telomeres and replicative cellular aging of the human placenta and chorioamniotic membranes

Recent hypotheses propose that the human placenta and chorioamniotic membranes (CAMs) experience telomere length (TL)-mediated senescence. These hypotheses are based on mean TL (mTL) measurements, but replicative senescence is triggered by short and dysfunctional telomeres, not mTL. We measured short telomeres by a vanguard method, the Telomere shortest length assay, and telomere-dysfunction-induced DNA damage foci (TIF) in placentas and CAMs between 18-week gestation and at full-term. Both the placenta and CAMs showed a buildup of short telomeres and TIFs, but not shortening of mTL from 18-weeks to full-term. In the placenta, TIFs correlated with short telomeres but not mTL. CAMs of preterm birth pregnancies with intra-amniotic infection showed shorter mTL and increased proportions of short telomeres. We conclude that the placenta and probably the CAMs undergo TL-mediated replicative aging. Further research is warranted whether TL-mediated replicative aging plays a role in all preterm births.

Cervical Pessary Plus Progesterone for Twin Pregnancy with Short Cervix Compared to Unselected and Non-Treated Twin Pregnancy: A Historical Equivalence Cohort Study (EPM Twin Pessary Study)

OBJECTIVE

 The present study aims to determine if the use of cervical pessary plus progesterone in short-cervix (≤ 25 mm) dichorionic-diamniotic (DC-DA) twin pregnancies is equivalent to the rate of preterm births (PBs) with no intervention in unselected DC-DA twin pregnancies.

METHODS

 A historical cohort study was performed between 2010 and 2018, including a total of 57 pregnant women with DC-DA twin pregnancies. The women admitted from 2010 to 2012 (n = 32) received no treatment, and were not selected by cervical length (Non-Treated group, NTG), whereas those admitted from 2013 to 2018 (n = 25), were routinely submitted to cervical pessary plus progesterone after the diagnosis of short cervix from the 18th to the 27th weeks of gestation (Pessary-Progesterone group, PPG). The primary outcome analyzed was the rate of PBs before 34 weeks.

RESULTS

 There were no statistical differences between the NTG and the PPG regarding PB < 34 weeks (18.8% versus 40.0% respectively; p = 0.07) and the mean birthweight of the smallest twin (2,037 ± 425 g versus 2,195 ± 665 g; p = 0.327). The Kaplan-Meyer Survival analysis was performed, and there were no differences between the groups before 31.5 weeks. Logistic regression showed that a previous PB (< 37 weeks) presented an odds ratio (OR) of 15.951 (95% confidence interval [95%CI]: 1.294-196.557; p = 0.031*) for PB < 34 weeks in the PPG.

CONCLUSION

 In DC-DA twin pregnancies with a short cervix, (which means a higher risk of PB), the treatment with cervical pessary plus progesterone could be considered equivalent in several aspects related to PB in the NTG, despite the big difference between these groups.

First trimester elevations of hematocrit, lipid peroxidation and nitrates in women with twin pregnancies who develop preeclampsia

Twin pregnancies are considered a risk factor for preeclampsia, an obstetric complication with high maternal and infant morbi-mortality. We hypothesize that alterations in maternal hematocrit, plasma lipid peroxidation and nitrates in the first trimester of pregnancy are associated with preeclampsia development in twin pregnancies. Blood samples were extracted from 102 healthy women with twin pregnancies at tenth week of gestation to assess hematological parameters and plasma levels of malondialdehyde and nitrates. Logistic regression model showed an association between red blood cells (OR = 38.8; p-value = 0.009), hematocrit (OR = 1.6; p-value = 0.017), malondialdehyde (OR = 1.5; p-value = 0.002), and nitrates (OR = 1.1; p-value = 0.045) and preeclampsia development. These parameters are potential biomarkers for early preeclampsia detection in twin pregnancies. Future research is needed to assess their value in predictive algorithms.

Both Low and High PAPP-A Concentrations in the First Trimester of Pregnancy Are Associated with Increased Risk of Delivery before 32 Weeks in Twin Gestation

In twin gestation, the relationship between pregnancy associated plasma protein (PAPP-A) and perinatal outcome is unclear. The aim of the study was to determine if low and high concentrations of PAPP-A in the first trimester are related to perinatal outcome in twins. A retrospective study was conducted. Medical data of women in twin pregnancies who delivered between 2013 and 2018 were analyzed. PAPP-A concentrations were measured between 10 + 0 and 13 + 6 weeks. The associations between low (<10th percentile) and high (>90th percentile) values of PAPP-A and pregnancy complications were analyzed. A total of 304 patients were included. PAPP-A <10th percentile was associated with a high risk of preterm delivery (OR 6.14; 95% CI 2.1-18), delivery <34 weeks (OR 2.39; 95% CI 1.1-5.1) or <32 weeks (OR3.06; 95% CI 1.4-6.8). Significant relations between PAPP-A >90th percentile and delivery <34 weeks (OR4.09; 95% CI 1.8-9.1) or <32 weeks (OR 2.83; 95% CI 1.2-6.6) were found. PAPP-A >90th percentile was related to high risk of intrauterine fetal demise (OR 10; 95% CI 2.4-42.5). Both low and high PAPP-A concentrations seem to be related to pregnancy outcome. Further research is needed to investigate evaluation of risk of pregnancy complications according to PAPP-A concentrations as a continuous variable.

Biochemical predictors of preterm birth in twin pregnancies: A systematic review involving 6077 twin pregnancies

In women with twin pregnancies biomarkers are not used to predict preterm birth in clinical practice. This systematic review assessed the risk of both spontaneous and iatrogenic preterm birth in twin pregnancies based on biochemical predictors. We searched the electronic databases from January 1990 to June 2019 without language restrictions. All studies on twin pregnancies where biochemical predictors and preterm birth were evaluated were included. We reported our findings as odds ratio (OR) with 95 % confidence intervals (CI) and pooled the estimates using random-effects meta-analysis for various predictor thresholds. From 12,623 citations, we included 33 studies involving 6077 pregnancies. The odds of preterm birth <28 weeks (OR 12.06, 95 % CI 4.90-29.70, I2 = 0%), <32 weeks (OR 10.03, 95 % CI 6.11-16.47, I2 = 0%), <34 weeks (OR 6.26, 95 % CI 3.85-10.17, I2 = 30 %), <37 weeks (OR 5.34, 95 % CI 3.68-7.76, I2 = 15 %) and delivery within 14 days of testing (OR 13.95, 95 % CI 4.33-44.98, I2 = 0%) was increased among women with a positive fetal Fibronectin (fFN) test who were either symptomatic or asymptomatic for preterm birth. Similarly, higher odds of preterm birth was also seen among twin pregnancies asymptomatic for preterm birth with a positive fFN test at gestations <32 weeks (OR 10.54, 95 % CI 5.66-19.64, I2 = 19 %), < 34 weeks (OR 8.07, 95 % CI 5.28-12.33, I2 = 0%) and < 37 weeks (OR 6.21, 95 % CI 4.34-8.87, I2 = 0%). As for other biomarkers, a significantly higher odds of preterm birth <37 weeks was seen among women with elevated maternal serum human Chorionic Gonadotrophin (mshCG) (OR 1.51, 95 % CI 1.07-2.13, I2 = 0%), 25 Hydroxy Vitamin D level <75 nmol/l (OR 2.59, 95 % CI 1.35-4.95, I2=NA), positive phosphorylated Insulin-like Growth Factor Binding Protein-1 (phIGFBP-1) (OR 4.23, 95 % CI 1.97-9.09, I2 = 0%) and in those with elevated Interleukin 8 (IL-8) (OR 3.13, 95 % CI 1.18-8.34, I2=NA). A higher odds of preterm birth at <34 weeks gestation was seen among women with maternal serum Alpha fetoprotein (AFP)>3.5 MoM (OR 2.35, 95 % CI 1.12-4.96, I2=NA) while higher odds of preterm birth at <32 weeks was seen among women with 25 Hydroxy Vitamin D level <75 nmol/l (OR 3.01, 95 % CI 1.26-7.19, I2=NA). Delivery within seven days of testing was significantly increased in women with a positive Matrix Metallo Protein-8 (MMP-8) test (OR 10.59, 95 % CI 3.70-30.29, I2=NA). Fetal Fibronectin is strongly associated with predicting preterm birth among women with twin pregnancies who are either asymptomatic or symptomatic for preterm birth as well as in those asymptomatic for preterm birth. Other biomarkers have shown a positive association in the prediction of preterm birth among women with twin pregnancies. Further studies are recommended to evaluate their role.

The Predictive Value of the Cervical Consistency Index to Predict Spontaneous Preterm Birth in Asymptomatic Twin Pregnancies at the Second-Trimester Ultrasound Scan: A Prospective Cohort Study

Novel transvaginal ultrasound (TVU) markers have been proposed to improve spontaneous preterm birth (sPTB) prediction. Preliminary results of the cervical consistency index (CCI), uterocervical angle (UCA), and cervical texture (CTx) have been promising in singletons. However, in twin pregnancies, the results have been inconsistent. In this prospective cohort study of asymptomatic twin pregnancies assessed between 18⁺⁰–22⁺⁰ weeks, we evaluated TVU derived cervical length (CL), CCI, UCA, and the CTx to predict sPTB < 34⁺⁰ weeks. All iatrogenic PTB were excluded. In the final cohort of 63 pregnancies, the sPTB rate < 34⁺⁰ was 16.3%. The CCI, UCA, and CTx, including the CL was significantly different in the sPTB < 34⁺⁰ weeks group. The best area under the receiver operating characteristic curve (AUC) for sPTB < 34⁺⁰ weeks was achieved by the CCI 0.82 (95%CI, 0.72–0.93), followed by the UCA with AUC 0.72 (95%CI, 0.57–0.87). A logistic regression model incorporating parity, chorionicity, CCI, and UCA resulted in an AUC of 0.91 with a sensitivity of 55.3% and specificity of 88.1% for predicting sPTB < 34⁺⁰. The CCI performed better than other TVU markers to predict sPTB < 34⁺⁰ in twin gestations, and the best diagnostic accuracy was achieved by a combination of parity, chorionicity, CCI, and UCA.

Twin pregnancies: can sonographic measurements and changes in cervical length during pregnancy predict preterm birth?

Objective: This study measured cervical length (CL) at 14-16 and 21-24 weeks of gestation and assessed whether the difference between measurements is predictive of preterm birth (PTB) among asymptomatic women with twin gestations.Method: This retrospective, cohort study included patients with two consecutive CL measurements with transvaginal sonography at 14-16 weeks of gestation (CL1) and 21-24 weeks (CL2). PTB was defined as delivery prior to 37 + 0 weeks of gestation. Electronic medical records were reviewed for demographic, medical and delivery data. CL1, CL2 and the change between scans were evaluated and correlated with the prediction of PTB.Results: Among 103 women with twin gestations, 76 (73.7%) delivered at term and 27 (26.3%) had PTB. CL1 and CL2 were not good predictors of PTB (p = .32 and p = .38, respectively). The correlation between CL change and PTB was not significant (p = .08). The correlation between CL change and delivery after 38 weeks was not significant (p = .3). Baseline characteristics and perinatal outcomes between term and preterm deliveries were similar.Conclusions: The delta between routine cervical length measurements at 14-16 and 21-24 weeks of twin gestations cannot be used as a reliable predictor of PTB.

Single and repeat cervical-length measurement in twin gestation with threatened preterm labor

OBJECTIVE

To examine the effectiveness of single and repeat sonographic cervical-length (CL) measurement in predicting preterm delivery in symptomatic women with a twin pregnancy.

METHODS

This was a retrospective study of women with a twin gestation who presented with painful and regular uterine contractions at 24 + 0 to 33 + 6 weeks' gestation at the perinatal unit of the University Hospital of Tübingen, Tübingen, Germany between 2012 and 2018. CL was measured on transvaginal ultrasound at the time of admission and a few days later after cessation of contractions. Treatment included administration of tocolytics (usually oral nifedipine), for no more than 48 h, and administration of steroids if CL was ≤ 25 mm. Patients were clustered into five groups according to the CL measurement obtained at first assessment: < 10.0 mm; between 10.0 and 14.9 mm; between 15.0 and 19.9 mm; between 20.0 and 24.9 mm; and ≥ 25.0 mm. For each group, we calculated the test performance of CL measurement for prediction of preterm delivery within the subsequent 7 days and before 34 weeks' gestation. Regression analysis was used to evaluate the test performance of the second CL measurement for predicting preterm delivery within 7 days after the second assessment.

RESULTS

The study population consisted of 257 twin pregnancies, of which 80.2% were dichorionic diamniotic. Median maternal and gestational ages at the time of admission were 32.0 years and 29.9 weeks' gestation, respectively. Preterm birth within 7 days of admission occurred in 23 (8.9%) pregnancies, and 82 (31.9%) patients delivered prior to 34 weeks' gestation. Median CL for the entire study population was 17.0 mm. Delivery within 7 days after the first assessment occurred in 29.0%, 10.6%, 4.2%, 6.3% and 0% of women with CL < 10.0 mm, 10.0-14.9 mm, 15.0-19.9 mm, 20.0-24.9 mm and ≥ 25.0 mm, respectively. There was a weak, but significant, association between the CL measurement at the time of admission and the time interval between admission and delivery (interval = 27.9 + 0.58 × CL; P = 0.003, r = 0.184). CL was measured again after a median time interval of 3 (interquartile range (IQR), 2-5) days in 248 cases. Median second CL measurement was 17.0 (IQR, 11.5-22.0) mm. Delivery occurred within the subsequent 7 days after the second measurement in 25/248 (10.1%) cases. Binary regression analysis indicated that the first (odds ratio (OR), 0.895; P = 0.003) and second (OR, 0.908; P = 0.002) CL measurements, but not the difference between the two measurements (OR, 0.961; P = 0.361), were associated significantly with delivery within 7 days after the second measurement. Receiver-operating-characteristics (ROC)-curve analysis for the prediction of delivery within 7 days after the second assessment did not show a significant difference between the predictive performance of the first (area under ROC curve (AUC), 0.676 (95% CI, 0.559-0.793)) and the second (AUC, 0.661 (95% CI, 0.531-0.790)) measurement.

CONCLUSION

Sonographic measurement of CL can be helpful in predicting preterm delivery within 7 days of presentation in symptomatic women with a twin gestation; however, the test performance is relatively weak. Copyright © 2019 ISUOG. Published by John Wiley & Sons Ltd.

Maternal Antioxidant Status in Early Pregnancy and Development of Fetal Complications in Twin Pregnancies: A Pilot Study

Twin pregnancies are increasing due to the rise in mothers' childbearing age and have a higher risk of fetal growth restriction (FGR) and prematurity. Therefore, early prediction of these events is important. Our aim was to analyze in the first trimester of pregnancy a possible association between antioxidants, including melatonin, in maternal plasma and the development of fetal complications in twin pregnancies. A single-center, prospective, and observational study was performed in 104 twin-pregnant women. A blood sample was extracted between the 9th and the 11th week of gestation, and plasma was obtained. Antioxidants (thiols, reduced glutathione, phenolic compounds, catalase, superoxide dismutase) and oxidative damage biomarkers (carbonyl groups and malondialdehyde) were assessed by spectrophotometry, and global scores were calculated from these parameters (Antiox-S, Prooxy-S). Melatonin and cortisol were evaluated by a competitive immunoassay. In the first trimester of pregnancy, Antiox-S was significantly lower in women who developed FGR compared to those with normal fetal growth; plasma melatonin was significantly lower in women with preterm compared to those with full-term births and exhibited a positive correlation with birth weight. Maternal cortisol showed a negative correlation with birth weight. We conclude that, for twin gestations, maternal plasma antioxidant status and melatonin could be potential biomarkers to be included in algorithms to predict FGR and preterm labor.

The fetal fibronectin test is superior to cervical length measurement in predicting preterm birth in twin pregnancies: a retrospective observational study

OBJECTIVES

Twin pregnancies have a higher likelihood to experience spontaneous preterm birth (PTB). Those with imminent PTB need to be determined in order to undergo fetal lung maturation with glucocorticoids and therewith improve neonatal outcomes. The aim of this study was to assess the predictive value of the fetal fibronectin (fFN) test and the measurement of cervical length in twin pregnancies with symptoms of imminent PTB.

STUDY DESIGN

We performed an observational study on all twin pregnancies at the Medical University Vienna. Women were admitted to the hospital either due to symptoms of imminent PTB or due to a shortening of the cervical length before completed 34 weeks of gestational age. Logistic regression analysis was performed to assess the predictive value of the fFN test and cervical length on imminent preterm birth.

RESULTS

The data of 82 women with twin pregnancies were eligible, of which 10 (12 %) had a positive, 45 (55 %) a negative, 21 (26 %) an unclear fFN result, and 6 (7 %) showed missing data. Cervical length ≤20 mm did not show any statistical significant prediction of PTB in our study cohort. After 7 days, 4/10 (40 %) pregnant women with positive fFN test gave birth, while 4/45 (9 %) women with a negative fFN test gave birth. Within 14 days after hospitalization, 6/10 (60 %) women with a positive fFN test gave birth, compared to 4/45 (9 %) with a negative fFN test. The positive fFN test was a statistically significant predictor of PTB within 7 days (p = 0.02) and 14 days (p = 0.004), respectively.

CONCLUSION

The fFN test has the potential to detect women with twin pregnancies, who are at risk of giving birth within the following days. Hence, the practice of hospitalizing women solely due to the shortening of the cervical length cannot be supported.

Preterm labor is characterized by a high abundance of amniotic fluid prostaglandins in patients with intra-amniotic infection or sterile intra-amniotic inflammation

Objective: To distinguish between prostaglandin and prostamide concentrations in the amniotic fluid of women who had an episode of preterm labor with intact membranes through the utilisation of liquid chromatography-tandem mass spectrometry.Study design: Liquid chromatography-tandem mass spectrometry analysis of amniotic fluid of women with preterm labor and (1) subsequent delivery at term (2) preterm delivery without intra-amniotic inflammation; (3) preterm delivery with sterile intra-amniotic inflammation (interleukin (IL)-6>2.6 ng/mL without detectable microorganisms); and (4) preterm delivery with intra-amniotic infection [IL-6>2.6 ng/mL with detectable microorganisms].Results: (1) amniotic fluid concentrations of PGE₂, PGF_2α, and PGFM were higher in patients with intra-amniotic infection than in those without intra-amniotic inflammation; (2) PGE₂ and PGF_2α concentrations were also greater in patients with intra-amniotic infection than in those with sterile intra-amniotic inflammation; (3) patients with sterile intra-amniotic inflammation had higher amniotic fluid concentrations of PGE₂ and PGFM than those without intra-amniotic inflammation who delivered at term; (4) PGFM concentrations were also greater in women with sterile intra-amniotic inflammation than in those without intra-amniotic inflammation who delivered preterm; (5) amniotic fluid concentrations of prostamides (PGE₂-EA and PGF_2α-EA) were not different among patients with preterm labor; (6) amniotic fluid concentrations of prostaglandins, but no prostamides, were higher in cases with intra-amniotic inflammation; and (7) the PGE₂:PGE₂-EA and PGF_2α:PGF_2α-EA ratios were higher in patients with intra-amniotic infection compared to those without inflammation.Conclusions: Mass spectrometric analysis of amniotic fluid indicated that amniotic fluid concentrations of prostaglandins, but no prostamides, were higher in women with preterm labor and intra-amniotic infection than in other patients with an episode of preterm labor. Yet, women with intra-amniotic infection had greater amniotic fluid concentrations of PGE₂ and PGF_2α than those with sterile intra-amniotic inflammation, suggesting that these two clinical conditions may be differentiated by using mass spectrometric analysis of amniotic fluid.

SMFM Special Statement: State of the science on multifetal gestations: unique considerations and importance

We sought to review the state of the science for research on multiple gestations. A literature search was performed with the use of PubMed for studies to quantify the representation of multiple gestations for a sample period (2012-2016) that were limited to phase III and IV randomized controlled trials, that were written in English, and that addressed at least 1 of 4 major pregnancy complications: fetal growth restriction or small-for-gestational-age fetus, gestational diabetes mellitus, preeclampsia, and preterm delivery. Of the 226 studies that are included in the analysis, multiple pregnancies were most represented in studies of preterm delivery: 17% of trials recruited both singleton and multiple pregnancies; another 18% of trials recruited only multiple pregnancies. For trials that studied preeclampsia, fetal growth restriction, and gestational diabetes mellitus, 17%, 8%, and 2%, respectively, recruited both singleton and multiple gestations. None of the trials on these 3 topics were limited to women with a multiple pregnancy. Women with a multiple pregnancy are at risk for complications similar to those of women with singleton pregnancies, but their risk is usually higher. Also, the pathophysiologic condition for some complications differs in multiple gestations from those that occur in singleton gestations. Conditions that are unique to multiple pregnancies include excess placenta, placental crowding or inability of the uteroplacental unit to support the normal growth of multiple fetuses, or suboptimal placental implantation sites with an increased risk of abnormal placental location. Other adverse outcomes in multiple gestations are also influenced by twin-specific risk factors, most notably chorionicity. Although twins have been well represented in many studies of preterm birth, these studies have failed to identify adequate predictive tests (short cervical length established over 2 decades ago remains the single best predictor), to establish effective interventions, and to differentiate the underlying pathophysiologic condition of twin preterm birth. Questions about fetal growth also remain. Twin growth deviates from that of singleton gestations starting at approximately 32 weeks of gestation; however, research with long-term follow-up is needed to better distinguish pathologic and physiologic growth deviations, which include growth discordance among pairs (or more). There are virtually no clinical trials that are specific to twins for gestational diabetes mellitus or preeclampsia, and subgroups for multiple pregnancies in existing trials are not large enough to allow definite conclusions. Another important area is the determination of appropriate maternal nutrition or micronutrient supplementation to optimize pregnancy and child health. There are also unique aspects to consider for research design in multiple gestations, such as designation and tracking of the correct fetus prenatally and through delivery. The correct statistical methods must be used to account for correlated data because multiple fetuses share the same mother and intrauterine environment. In summary, multiple gestations often are excluded from research studies, despite a disproportionate contribution to national rates of perinatal morbidity, mortality, and health-care costs. It is important to consider the enrollment of multifetal pregnancies in studies that target mainly women with singleton gestations, even when sample size is inadequate, so that insights that are specific to multiple gestations can be obtained when results of smaller studies are pooled together. The care of pregnant women with multiple gestations presents unique challenges; unfortunately, evidence-based clinical management that includes the diagnosis and treatment of common obstetrics problems are not well-defined for this population.

The prediction of early preeclampsia: Results from a longitudinal proteomics study

OBJECTIVES

To identify maternal plasma protein markers for early preeclampsia (delivery <34 weeks of gestation) and to determine whether the prediction performance is affected by disease severity and presence of placental lesions consistent with maternal vascular malperfusion (MVM) among cases.

STUDY DESIGN

This longitudinal case-control study included 90 patients with a normal pregnancy and 33 patients with early preeclampsia. Two to six maternal plasma samples were collected throughout gestation from each woman. The abundance of 1,125 proteins was measured using high-affinity aptamer-based proteomic assays, and data were modeled using linear mixed-effects models. After data transformation into multiples of the mean values for gestational age, parsimonious linear discriminant analysis risk models were fit for each gestational-age interval (8-16, 16.1-22, 22.1-28, 28.1-32 weeks). Proteomic profiles of early preeclampsia cases were also compared to those of a combined set of controls and late preeclampsia cases (n = 76) reported previously. Prediction performance was estimated via bootstrap.

RESULTS

We found that 1) multi-protein models at 16.1-22 weeks of gestation predicted early preeclampsia with a sensitivity of 71% at a false-positive rate (FPR) of 10%. High abundance of matrix metalloproteinase-7 and glycoprotein IIbIIIa complex were the most reliable predictors at this gestational age; 2) at 22.1-28 weeks of gestation, lower abundance of placental growth factor (PlGF) and vascular endothelial growth factor A, isoform 121 (VEGF-121), as well as elevated sialic acid binding immunoglobulin-like lectin 6 (siglec-6) and activin-A, were the best predictors of the subsequent development of early preeclampsia (81% sensitivity, FPR = 10%); 3) at 28.1-32 weeks of gestation, the sensitivity of multi-protein models was 85% (FPR = 10%) with the best predictors being activated leukocyte cell adhesion molecule, siglec-6, and VEGF-121; 4) the increase in siglec-6, activin-A, and VEGF-121 at 22.1-28 weeks of gestation differentiated women who subsequently developed early preeclampsia from those who had a normal pregnancy or developed late preeclampsia (sensitivity 77%, FPR = 10%); 5) the sensitivity of risk models was higher for early preeclampsia with placental MVM lesions than for the entire early preeclampsia group (90% versus 71% at 16.1-22 weeks; 87% versus 81% at 22.1-28 weeks; and 90% versus 85% at 28.1-32 weeks, all FPR = 10%); and 6) the sensitivity of prediction models was higher for severe early preeclampsia than for the entire early preeclampsia group (84% versus 71% at 16.1-22 weeks).

CONCLUSION

We have presented herein a catalogue of proteome changes in maternal plasma proteome that precede the diagnosis of preeclampsia and can distinguish among early and late phenotypes. The sensitivity of maternal plasma protein models for early preeclampsia is higher in women with underlying vascular placental disease and in those with a severe phenotype.

Effectiveness and Accuracy of Tests for Preterm Delivery in Symptomatic Women: A Systematic Review

This study systematically reviewed evidence on the effectiveness and accuracy of predictive tests for preterm delivery among symptomatic women. The study included English-language systematic reviews (SRs) on any predictive test for preterm delivery among symptomatic women and primary studies for placental alpha-microglobulin-1. PubMed, Wiley Cochrane Library, the Centre for Reviews and Dissemination Database, the National Guidelines Clearinghouse, and the TRIP database were searched for SRs, PubMed and PubMed Central via the Wiley Cochrane Library were searched for primary studies. One reviewer performed study selection, with input from a second reviewer when needed. One reviewer appraised study quality and extracted: study characteristics (i.e., country, funding source, study design [primary studies] or synthesis method [SRs], study appraisal method [SRs]), population characteristics, index test(s) and cut-off points used, comparator(s) or reference standard(s), and outcomes. A second reviewed a random 10% sample. The authors synthesized the findings narratively. Of 451 unique records, the review included 22 (17 SRs, five primary studies). For effectiveness, there was evidence for use of transvaginal sonographic cervical length assessment (15-25 mm cut point) in reducing incidence of preterm delivery at <37 weeks (relative risk 0.64; 95% CI 0.44-0.94, one SR of three trials; n = 287) but lack of support for cervicovaginal fetal fibronectin. In terms of accuracy, one high-quality study within a best-evidence SR showed that cervical length measurement was useful to predict delivery within 48 hours (LR+ 6.43, 95% CI 5.17-8.00; LR- 0.03, 95% CI 0.00-0.42; n = 510) and 7 days (LR+ 8.61, 95% CI 6.65-11.14; LR- 0.03, 95% CI 0.00-0.18; n = 510). Accuracy of placental alpha-microglobulin-1 testing was not supported for most end points. In conclusion, some evidence supports the effectiveness of cervical length as a predictor of preterm delivery in symptomatic women. Evidence for most tests is limited in quality and quantity.

National policies and care provision in pregnancy and childbirth for twins in Eastern and Southern Africa: A mixed-methods multi-country study

BACKGROUND

High-risk pregnancies, such as twin pregnancies, deserve particular attention as mortality is very high in this group. With a view to inform policy and national guidelines development for the Sustainable Development Goals, we reviewed national training materials, guidelines, and policies underpinning the provision of care in relation to twin pregnancies and assessed care provided to twins in 8 Eastern and Southern African countries: Kenya, Malawi, Mozambique, Rwanda, Tanzania, Uganda, Zambia, and Zimbabwe.

METHODS AND FINDINGS

We located policies and guidelines by reviewing national repositories and by contacting experts to systematically map country-level maternal and newborn training materials, guidelines, and policies. We extracted recommendations for care for twins spanning ante-, intra-, and postpartum care that typically should be offered during twin pregnancies and childbirth. We compared care provided for mothers of twins to that provided for mothers of singletons during the ante-, intra-, and postpartum period and computed neonatal mortality rates using the most recent Demographic and Health Surveys (DHS) data for each country. There was a paucity of guidance on care specifically for twin or multiple pregnancies: None of the countries provided clear guidance on additional number of antenatal care visits or specific antenatal content, while 7 of the 8 countries recommended twins to be delivered in a comprehensive emergency obstetric and neonatal care facility. These results were mirrored by DHS results of 73,462 live births (of which 1,360 were twin) indicating that twin pregnancies did not receive more frequent or intensified antenatal care. The percentage of twin deliveries in hospitals varied from 25.3% in Mozambique to 63.0% in Kenya, and women with twin deliveries were between 5 and 27 percentage points more likely to deliver in hospitals compared to women with singleton live births; this difference was significant in 5 of the 8 countries (t test p < 0.05). The percentage of twin deliveries by cesarean section varied from 9% in Mozambique to 36% in Rwanda. The newborn mortality rate among twins, adjusted for maternal age and parity, was 4.6 to 7.2 times higher for twins compared to singletons in all 8 countries.

CONCLUSIONS

Despite the limited sample size and the limited number of clinically relevant services evaluated, our study provided evidence that mothers of twins receive insufficient care and that mortality in twin newborns is very high in Eastern and Southern Africa. Most countries have insufficient guidelines for the care of twins. While our data do not allow us to make a causal link between insufficient guidelines and insufficient care, they call for an assessment and reconceptualisation of policies to reduce the unacceptably high mortality in twins in Eastern and Southern Africa.

The fetal fibronectin test: 25 years after its development, what is the evidence regarding its clinical utility? A systematic review and meta-analysis

Background: The identification of women at risk for preterm birth should allow interventions which could improve neonatal outcome. Fetal fibronectin, a glycoprotein which acts normally as glue between decidua and amniotic membranes could be a good marker of impending labour when its concentration in cervicovaginal secretions between 22 and 36 weeks of gestation is ≥50 ng/mL. Many authors worldwide have tested this marker with many different methodologies and clinical settings, but conclusions about its clinical use are mixed. It is time for a comprehensive update through a systematic review and meta-analysis.Methods: We searched PubMed, Cochrane Library, and Embase, supplemented by manual search of bibliographies of known primary and review articles, international conference papers, and contact with experts from 1-1990 to 2-2018. We have selected all type of studies involving fetal fibronectin test accuracy for preterm delivery. Two authors independently extracted data about study characteristics and quality from identified publications. Contingency tables were constructed. Reference standards were preterm delivery before 37, 36, 35, 34, and 32 weeks, within 28, 21, 14, or 7 d and within 48 h. Data were pooled to produce summary likelihood ratios for positive and negative tests results.Results: One hundred and ninety-three primary studies were identified allowing analysis of 53 subgroups. In all settings, none of the summary likelihood ratios were >10 or <0.1, thus indicating moderate prediction, particularly in asymptomatic women and in multiple gestations.Conclusions: The fetal fibronectin test should not be used as a screening test for asymptomatic women. For high-risk asymptomatic women, and especially for women with multiple pregnancies, the performance of the fetal fibronectin test was also too low to be clinically relevant. Consensual use as a diagnostic tool for women with suspected preterm labor, the best use policy probably still depends on local contingencies, future cost-effectiveness analysis, and comparison with other more recent available biochemical markers.

Inflammation induced preterm labor and birth

Preterm birth which occurs before 37 weeks gestation is one of the most common obstetrical complication in humans. After many studies, it appears that "not one answer fits all" regarding the risk factors, causes and the treatments for this syndrome. However, it is becoming more evident that one of the major risk factors is inflammation and/or infection in the fetoplacental unit. In animal models (usually consisting of mice injected with lipopolysaccharide at 14 days of gestation), IL-22 and IL-6 have been identified as factors related to preterm birth. There are some clinical tests available to determine the risk for preterm labor and delivery, which can be identified before, during early, or at mid-gestation. However, treatment of preterm birth with antibiotics so far has not been "curable" and studies using anti-inflammatory treatments are not readily available. More studies regarding causes and treatments for preterm labor and delivery in humans are necessary to prevent neonatal deaths and/or developmental abnormalities associated with this common syndrome.

Vaginal progesterone is as effective as cervical cerclage to prevent preterm birth in women with a singleton gestation, previous spontaneous preterm birth, and a short cervix: updated indirect comparison meta-analysis

BACKGROUND

An indirect comparison meta-analysis published in 2013 reported that both vaginal progesterone and cerclage are equally efficacious for preventing preterm birth and adverse perinatal outcomes in women with a singleton gestation, previous spontaneous preterm birth, and a sonographic short cervix. The efficacy of vaginal progesterone has been challenged after publication of the OPPTIMUM study. However, this has been resolved by an individual patient-data meta-analysis (Am J Obstet Gynecol. 2018;218:161-180).

OBJECTIVE

To compare the efficacy of vaginal progesterone and cerclage in preventing preterm birth and adverse perinatal outcomes in women with a singleton gestation, previous spontaneous preterm birth, and a midtrimester sonographic short cervix.

DATA SOURCES

MEDLINE, EMBASE, LILACS, and CINAHL (from their inception to March 2018); Cochrane databases, bibliographies, and conference proceedings.

STUDY ELIGIBILITY CRITERIA

Randomized controlled trials comparing vaginal progesterone to placebo/no treatment or cerclage to no cerclage in women with a singleton gestation, previous spontaneous preterm birth, and a sonographic cervical length <25 mm.

STUDY APPRAISAL AND SYNTHESIS METHODS

Updated systematic review and adjusted indirect comparison meta-analysis of vaginal progesterone vs cerclage using placebo/no cerclage as the common comparator. The primary outcomes were preterm birth <35 weeks of gestation and perinatal mortality. Pooled relative risks (RRs) with 95% confidence intervals were calculated.

RESULTS

Five trials comparing vaginal progesterone vs placebo (265 women) and 5 comparing cerclage vs no cerclage (504 women) were included. Vaginal progesterone, compared to placebo, significantly reduced the risk of preterm birth <35 and <32 weeks of gestation, composite perinatal morbidity/mortality, neonatal sepsis, composite neonatal morbidity, and admission to the neonatal intensive care unit (RRs from 0.29 to 0.68). Cerclage, compared to no cerclage, significantly decreased the risk of preterm birth <37, <35, <32, and <28 weeks of gestation, composite perinatal morbidity/mortality, and birthweight <1500 g (RRs from 0.64 to 0.70). Adjusted indirect comparison meta-analyses did not show statistically significant differences between vaginal progesterone and cerclage in the reduction of preterm birth or adverse perinatal outcomes.

CONCLUSION

Vaginal progesterone and cerclage are equally effective for preventing preterm birth and improving perinatal outcomes in women with a singleton gestation, previous spontaneous preterm birth, and a midtrimester sonographic short cervix. The choice of treatment will depend on adverse events and cost-effectiveness of interventions and patient/physician's preferences.

Accuracy of fetal fibronectin for the prediction of preterm birth in symptomatic twin pregnancies: a pilot study

Our goal was to evaluate the performance of fetal fibronectin (fFN) test alone or combined with cervical length (CL), to predict spontaneous preterm birth (PTB) in symptomatic twin pregnancies. We carry out a short pilot study including all uncomplicated diamniotic twin pregnancies with symptoms of preterm labor (PTL) and intact membranes at 24-33 weeks + 6 days of gestation. Studied outcome were spontaneous delivery within 7 and 14 days of testing and spontaneous PTB at <34 and <37 weeks of gestation. Among 40 women, fFN test was positive in 3 of them (7.5%). Regardless of the outcome studied CL did not significantly predict PTB. Performance of fFN was sensitivity (66.7%), specificity (97.2%), positive predictive value (66.7%), negative predictive value (97.2%), positive likelihood ratio (LR) (24.0), and negative LR (0.3) to predict spontaneous PTB within 7 days (p = 0.01). Thus, 66.1% of patients with a positive fFN test would deliver within 7 days versus 2.4% if negative testing; starting with a pre-test probability of 7.5%. Combining CL and fFN did not enable to increase enough positive LR or decrease significantly negative LR. In conclusion, fFN test alone might have a better ability to detect spontaneous delivery within 7 days among symptomatic twin pregnancies.

Vaginal progesterone for preventing preterm birth and adverse perinatal outcomes in singleton gestations with a short cervix: a meta-analysis of individual patient data

BACKGROUND

The efficacy of vaginal progesterone for preventing preterm birth and adverse perinatal outcomes in singleton gestations with a short cervix has been questioned after publication of the OPPTIMUM study.

OBJECTIVE

To determine whether vaginal progesterone prevents preterm birth and improves perinatal outcomes in asymptomatic women with a singleton gestation and a midtrimester sonographic short cervix.

STUDY DESIGN

We searched MEDLINE, EMBASE, LILACS, and CINAHL (from their inception to September 2017); Cochrane databases; bibliographies; and conference proceedings for randomized controlled trials comparing vaginal progesterone vs placebo/no treatment in women with a singleton gestation and a midtrimester sonographic cervical length ≤25 mm. This was a systematic review and meta-analysis of individual patient data. The primary outcome was preterm birth <33 weeks of gestation. Secondary outcomes included adverse perinatal outcomes and neurodevelopmental and health outcomes at 2 years of age. Individual patient data were analyzed using a 2-stage approach. Pooled relative risks with 95% confidence intervals were calculated. Quality of evidence was assessed using the GRADE methodology.

RESULTS

Data were available from 974 women (498 allocated to vaginal progesterone, 476 allocated to placebo) with a cervical length ≤25 mm participating in 5 high-quality trials. Vaginal progesterone was associated with a significant reduction in the risk of preterm birth <33 weeks of gestation (relative risk, 0.62; 95% confidence interval, 0.47-0.81; P = .0006; high-quality evidence). Moreover, vaginal progesterone significantly decreased the risk of preterm birth <36, <35, <34, <32, <30, and <28 weeks of gestation; spontaneous preterm birth <33 and <34 weeks of gestation; respiratory distress syndrome; composite neonatal morbidity and mortality; birthweight <1500 and <2500 g; and admission to the neonatal intensive care unit (relative risks from 0.47-0.82; high-quality evidence for all). There were 7 (1.4%) neonatal deaths in the vaginal progesterone group and 15 (3.2%) in the placebo group (relative risk, 0.44; 95% confidence interval, 0.18-1.07; P = .07; low-quality evidence). Maternal adverse events, congenital anomalies, and adverse neurodevelopmental and health outcomes at 2 years of age did not differ between groups.

CONCLUSION

Vaginal progesterone decreases the risk of preterm birth and improves perinatal outcomes in singleton gestations with a midtrimester sonographic short cervix, without any demonstrable deleterious effects on childhood neurodevelopment.

Vaginal progesterone for preventing preterm birth and adverse perinatal outcomes in singleton gestations with a short cervix: a meta-analysis of individual patient data

BACKGROUND

The efficacy of vaginal progesterone for preventing preterm birth and adverse perinatal outcomes in singleton gestations with a short cervix has been questioned after publication of the OPPTIMUM study.

OBJECTIVE

To determine whether vaginal progesterone prevents preterm birth and improves perinatal outcomes in asymptomatic women with a singleton gestation and a midtrimester sonographic short cervix.

STUDY DESIGN

We searched MEDLINE, EMBASE, LILACS, and CINAHL (from their inception to September 2017); Cochrane databases; bibliographies; and conference proceedings for randomized controlled trials comparing vaginal progesterone vs placebo/no treatment in women with a singleton gestation and a midtrimester sonographic cervical length ≤25 mm. This was a systematic review and meta-analysis of individual patient data. The primary outcome was preterm birth <33 weeks of gestation. Secondary outcomes included adverse perinatal outcomes and neurodevelopmental and health outcomes at 2 years of age. Individual patient data were analyzed using a 2-stage approach. Pooled relative risks with 95% confidence intervals were calculated. Quality of evidence was assessed using the GRADE methodology.

RESULTS

Data were available from 974 women (498 allocated to vaginal progesterone, 476 allocated to placebo) with a cervical length ≤25 mm participating in 5 high-quality trials. Vaginal progesterone was associated with a significant reduction in the risk of preterm birth <33 weeks of gestation (relative risk, 0.62; 95% confidence interval, 0.47-0.81; P = .0006; high-quality evidence). Moreover, vaginal progesterone significantly decreased the risk of preterm birth <36, <35, <34, <32, <30, and <28 weeks of gestation; spontaneous preterm birth <33 and <34 weeks of gestation; respiratory distress syndrome; composite neonatal morbidity and mortality; birthweight <1500 and <2500 g; and admission to the neonatal intensive care unit (relative risks from 0.47-0.82; high-quality evidence for all). There were 7 (1.4%) neonatal deaths in the vaginal progesterone group and 15 (3.2%) in the placebo group (relative risk, 0.44; 95% confidence interval, 0.18-1.07; P = .07; low-quality evidence). Maternal adverse events, congenital anomalies, and adverse neurodevelopmental and health outcomes at 2 years of age did not differ between groups.

CONCLUSION

Vaginal progesterone decreases the risk of preterm birth and improves perinatal outcomes in singleton gestations with a midtrimester sonographic short cervix, without any demonstrable deleterious effects on childhood neurodevelopment.

The maternal plasma proteome changes as a function of gestational age in normal pregnancy: a longitudinal study

OBJECTIVE

Pregnancy is accompanied by dramatic physiological changes in maternal plasma proteins. Characterization of the maternal plasma proteome in normal pregnancy is an essential step for understanding changes to predict pregnancy outcome. The objective of this study was to describe maternal plasma proteins that change in abundance with advancing gestational age and determine biological processes that are perturbed in normal pregnancy.

STUDY DESIGN

A longitudinal study included 43 normal pregnancies that had a term delivery of an infant who was appropriate for gestational age without maternal or neonatal complications. For each pregnancy, 3 to 6 maternal plasma samples (median, 5) were profiled to measure the abundance of 1125 proteins using multiplex assays. Linear mixed-effects models with polynomial splines were used to model protein abundance as a function of gestational age, and the significance of the association was inferred via likelihood ratio tests. Proteins considered to be significantly changed were defined as having the following: (1) >1.5-fold change between 8 and 40 weeks of gestation; and (2) a false discovery rate-adjusted value of P < .1. Gene ontology enrichment analysis was used to identify biological processes overrepresented among the proteins that changed with advancing gestation.

RESULTS

The following results were found: (1) Ten percent (112 of 1125) of the profiled proteins changed in abundance as a function of gestational age; (2) of the 1125 proteins analyzed, glypican-3, sialic acid-binding immunoglobulin-type lectin-6, placental growth factor, C-C motif-28, carbonic anhydrase 6, prolactin, interleukin-1 receptor 4, dual-specificity mitogen-activated protein kinase 4, and pregnancy-associated plasma protein-A had more than a 5-fold change in abundance across gestation (these 9 proteins are known to be involved in a wide range of both physiological and pathological processes, such as growth regulation, embryogenesis, angiogenesis immunoregulation, inflammation etc); and (3) biological processes associated with protein changes in normal pregnancy included defense response, defense response to bacteria, proteolysis, and leukocyte migration (false discovery rate, 10%).

CONCLUSION

The plasma proteome of normal pregnancy demonstrates dramatic changes in both the magnitude of changes and the fraction of the proteins involved. Such information is important to understand the physiology of pregnancy and the development of biomarkers to differentiate normal vs abnormal pregnancy and determine the response to interventions.

Impact of routine transvaginal ultrasound monitoring of cervical length in twins on administration of antenatal corticosteroids

OBJECTIVE

To evaluate whether routine measurement of cervical length (CL) by transvaginal ultrasound (TVU) in twin pregnancies can enable identification of women who will give birth before 34 weeks and require antenatal corticosteroids (ACSs), and whether it can limit their administration to women who will give birth later.

STUDY DESIGN

Retrospective comparative study in two tertiary referral centers in France. Women with twin gestations followed in two tertiary university hospital maternity units and who delivered from January 1, 2007 to December 31, 2009 were included. In one center, TVU was targeted to women with cases of suspected preterm labor, while the other center used it monthly for all twin pregnancies. The main outcome measure was the administration of a full course of ACS to twins delivered before 34 weeks.

RESULTS

Two hundred and seventy women were eligible in the "targeted use" group, and 296 women in the "routine use" group. The rate of administration of at least one full course of ACS for twins born before 34 weeks did not differ between the two groups (85.0% in the targeted use group and 90.0% in the routine use group, P=0.40), but the rate of such administration for those born after 34 weeks was lower in the targeted use group (25.7% vs. 81.2%, P<0.01). On adjusting for confounders using logistic regression modeling, no significant difference in ACS administration before 34 weeks was found between the two groups [adjusted odds ratio (aOR), 0.71, 95% confidence interval (CI), 0.39-1.30].

CONCLUSION

Routine monitoring performed every month of CL with TVU does not affect the rate of administration of ACS to twins born before 34 weeks, but is associated with a higher rate of such administration for those born later in the specific center of the study.

Vaginal progesterone decreases preterm birth and neonatal morbidity and mortality in women with a twin gestation and a short cervix: an updated meta-analysis of individual patient data

OBJECTIVE

To assess the efficacy of vaginal progesterone for the prevention of preterm birth and neonatal morbidity and mortality in asymptomatic women with a twin gestation and a sonographic short cervix (cervical length ≤ 25 mm) in the mid-trimester.

METHODS

This was an updated systematic review and meta-analysis of individual patient data (IPD) from randomized controlled trials comparing vaginal progesterone with placebo/no treatment in women with a twin gestation and a mid-trimester sonographic cervical length ≤ 25 mm. MEDLINE, EMBASE, POPLINE, CINAHL and LILACS (all from inception to 31 December 2016), the Cochrane Central Register of Controlled Trials, Research Registers of ongoing trials, Google Scholar, conference proceedings and reference lists of identified studies were searched. The primary outcome measure was preterm birth < 33 weeks' gestation. Two reviewers independently selected studies, assessed the risk of bias and extracted the data. Pooled relative risks (RRs) with 95% confidence intervals (CI) were calculated.

RESULTS

IPD were available for 303 women (159 assigned to vaginal progesterone and 144 assigned to placebo/no treatment) and their 606 fetuses/infants from six randomized controlled trials. One study, which included women with a cervical length between 20 and 25 mm, provided 74% of the total sample size of the IPD meta-analysis. Vaginal progesterone, compared with placebo/no treatment, was associated with a statistically significant reduction in the risk of preterm birth < 33 weeks' gestation (31.4% vs 43.1%; RR, 0.69 (95% CI, 0.51-0.93); moderate-quality evidence). Moreover, vaginal progesterone administration was associated with a significant decrease in the risk of preterm birth < 35, < 34, < 32 and < 30 weeks' gestation (RRs ranging from 0.47 to 0.83), neonatal death (RR, 0.53 (95% CI, 0.35-0.81)), respiratory distress syndrome (RR, 0.70 (95% CI, 0.56-0.89)), composite neonatal morbidity and mortality (RR, 0.61 (95% CI, 0.34-0.98)), use of mechanical ventilation (RR, 0.54 (95% CI, 0.36-0.81)) and birth weight < 1500 g (RR, 0.53 (95% CI, 0.35-0.80)) (all moderate-quality evidence). There were no significant differences in neurodevelopmental outcomes at 4-5 years of age between the vaginal progesterone and placebo groups.

CONCLUSION

Administration of vaginal progesterone to asymptomatic women with a twin gestation and a sonographic short cervix in the mid-trimester reduces the risk of preterm birth occurring at < 30 to < 35 gestational weeks, neonatal mortality and some measures of neonatal morbidity, without any demonstrable deleterious effects on childhood neurodevelopment. Published 2017. This article is a U.S. Government work and is in the public domain in the USA.

Myometrial cytokines and their role in the onset of labour

Human labour is an inflammatory event, physiologically driven by an interaction between hormonal and mechanical factors and pathologically associated with infection, bleeding and excessive uterine stretch. The initiation and communicators of inflammation is still not completely understood; however, a key role for cytokines has been implicated. We summarise the current understanding of the nature and role of cytokines, chemokines and hormones and their involvement in signalling within the myometrium particularly during labour.