Effectiveness of progestogens to improve perinatal outcome in twin pregnancies: an individual participant data meta-analysis

Development and validation of a nomogram for individualized prediction of spontaneous extremely preterm birth at < 28 weeks in twin pregnancy: a retrospective cohort study

PURPOSE

To develop a nomogram to predict spontaneous preterm birth at < 28 weeks in pregnant women with twin pregnancies.

METHODS

We retrospectively studied the medical records of twin-pregnancy women with asymptomatic cervical dilation or cervical shortening between December 2015 to February 2022 in two hospitals. Data from one center was used to develop the model and data from the other was used to evaluate the model.

RESULTS

A total of 270 twin pregnancies were enrolled in the study. We incorporated 4 items (cervical length, cervical dilation, C-reactive protein and the use of cerclage) to build the 28-week nomogram with satisfactory discrimination and calibration when applied to the validation sets. The C index for the 28-week nomogram in the development and external cohort was 0.88 (95% CI, 0.84-0.93) and 0.89 (95% CI, 0.80-0.98), respectively. The nomogram reached a sensitivity of 70.70%, specificity of 97.10%, positive predicted value of 95.61% and negative predicted value of 78.77%. Moreover, the decision curve analysis indicated that the nomogram showed positive clinical benefit.

CONCLUSION

We developed and validated a nomogram with good performance in predicting individual risk of spontaneous preterm birth at < 28 in twin pregnancy.

Pregnant Populations which Benefit from Vaginal Progesterone for Preventing Preterm Birth at <34 Weeks and Neonatal Morbidities: A Systematic Review and Meta-analysis

This study aimed to assess vaginal progesterone's effect on different populations and performed comparation between women with varied risk factors. Embase, PubMed, Cochrane library (CENTRAL) were searched without restriction to language up to February 25, 2021. Randomized controlled trials (RCTs) assessing vaginal progesterone administered to women at risk of preterm birth at <37 weeks. Two reviewers independently extracted data, and pooled relative risk (RR) with 95% confidence intervals (CIs) was calculated as well. Women with short cervix have a significantly lower risk of preterm birth at <34 weeks (pooled RR = 0.65; 95% CI: 0.55-0.77; I 2 = 0; p < 0.001; nine studies) and some neonatal morbidities; interaction tests showed that effect of vaginal progesterone differs significantly between women with short cervix and those with other risk factors (history of preterm birth, exclusive twin gestation, and vaginal bleeding). Evidences of this study showed that singleton gestations, as well as women with short cervix, benefit from vaginal progesterone in preventing preterm birth at <34 weeks and some neonatal morbidities. Women with short cervix are populations who benefit the most among other risk populations. KEY POINTS: · Vaginal progesterone reduces preterm birth and neonatal morbidities.. · Vaginal progesterone effects on some specific populations.. · Women with short cervix benefit the most..

Screening and Prevention of Preterm Birth in Twin Pregnancies

Twins represent 3.2% of all live births. However, they account for 20% of all preterm deliveries, 60% delivering <37 weeks, 10.7% <32 weeks, and 5 times higher risk of infant death. Risk factors for preterm birth (PTB) include the history of preterm delivery, monochorionic twins, short cervical length, and cervical surgery. Transvaginal cervical length <24 weeks is the best tool to predict PTB. Only vaginal progesterone in women with transvaginal cervical length <25 mm and physical exam indicated cerclage in women with cervical dilation >1 cm have shown a significant decrease in PTB and improvement in neonatal outcomes.

A new care pathway to optimize gestational weight gain in twin pregnancies

BACKGROUND

Maternal gestational weight gain is an important determinant of pregnancy outcomes and may have an even greater role in twin pregnancies because of their higher rate of pregnancy complications and greater nutritional demands. However, data on the optimal week-specific gestational weight gain in twin pregnancies and on interventions that should be applied in cases of inadequate gestational weight gain are limited.

OBJECTIVE

This study aimed to determine whether a new care pathway that involves monitoring gestational weight gain using a week-specific chart, along with a standardized protocol for managing cases with inadequate gestational weight gain, can optimize maternal gestational weight gain in twin pregnancies.

METHODS

In this study, patients with twin pregnancies followed in a single tertiary center between February 2021 and May 2022 were exposed to the new care pathway (postintervention group). Gestational weight gain and clinical outcomes were compared with those of a previously described cohort of patients with twins followed in our clinic before the implementation of the new care pathway (preintervention group). The new care pathway targeted patients and care providers and included educational material, a newly developed body mass index group-specific gestational weight gain chart, and a stepwise management algorithm in cases of inadequate gestational weight gain. The body mass index group-specific gestational weight gain charts were divided into 3 zones: (1) green zone (optimal gestational weight gain at 25th-75th centiles); (2) yellow zone (suboptimal gestational weight gain at 5th-24th or 76th-95th centiles); and (3) gray zone (abnormal gestational weight gain, at <5th or >95th centile). The primary outcome was the overall proportion of patients achieving optimal gestational weight gain at birth.

RESULTS

A total of 123 patients were exposed to the new care pathway and were compared with 1079 patients from the preintervention period. Patients in the postintervention group were more likely to achieve optimal gestational weight gain at birth (60.2% vs 47.7%; adjusted odds ratio, 1.91; 95% confidence interval, 1.28-2.86) and were less likely to achieve low-suboptimal gestational weight gain (7.3% vs 14.7%; adjusted odds ratio, 0.41; 95% confidence interval, 0.20-0.85) or any suboptimal gestational weight gain (26.8% vs 34.8%; adjusted odds ratio, 0.60; 95% confidence interval, 0.39-0.93) at birth. In addition, patients in the postintervention group were less likely to have low-abnormal gestational weight gain anytime during gestation (18.9% vs 29.1%; P=.017) and were more likely to have normal gestational weight gain throughout pregnancy (21.3% vs 14.0%; P=.031) or high-abnormal gestational weight gain anytime during gestation (18.0% vs 11.1%; P=.025), suggesting that in comparison with standard care, the new care pathway is more effective in preventing patients from moving into the low-abnormal zone than the high-abnormal zone. Furthermore, the new care pathway was more effective than standard care in correcting high-suboptimal gestational weight gain and high-abnormal gestational weight gain.

CONCLUSION

Our findings suggest that the new care pathway may be effective in optimizing maternal gestational weight gain in twin gestations, which may in turn contribute to better clinical outcomes. This is a simple, low-cost intervention that can be easily disseminated among providers caring for patients with twin pregnancies.

Cervical length screening for predicting preterm birth: A comparative review of guidelines

A cervical length (CL) assessment may predict preterm birth (PTB). This study aimed to analyze and compare the recommendations of guidelines on the role of CL in the prediction of PTB. There is no consensus regarding universal screening of asymptomatic women without a history of prior spontaneous PTB (sPTB), using CL. On the other hand, CL assessment is recommended in cases with a history of sPTB due to the high recurrence rate. Finally, there is discrepancy regarding CL assessment in asymptomatic women with multiple pregnancy. Although far from perfect, CL measurement remains the best available method to predict PTB.

Time interval to delivery in asymptomatic twin pregnancies with a short cervix at 23-28 weeks' gestation

OBJECTIVES

To evaluate the risk and timing of spontaneous preterm birth (PTB) in asymptomatic twin pregnancies with a short cervical length (CL≤25 mm) at 23-28 weeks of gestation.

METHODS

Multicenter retrospective cohort study of asymptomatic twin pregnancies with a short CL between 23 and 28 weeks' gestation within a university health system from 1/2012 to 12/2019. Cases were divided into 4 groups based on CL measurement (≤10 mm, 11-15 mm, 16-20 mm, and 21-25 mm). The primary outcome was time interval from presentation to delivery. Secondary outcomes included delivery within one and two weeks of presentation, and delivery prior to 32, 34, and 37 weeks, respectively.

RESULTS

104 patients were included. The time interval from presentation to delivery was significantly different among the four groups (p<0.001), with the CL≤10 mm group having the shortest time interval to delivery. Regardless of the CL measurement, spontaneous PTB within one and two weeks was extremely uncommon and occurred in only one patient within the study cohort (1/104, 1.0%). The risk of spontaneous PTB was highest in the shortest CL group (CL ≤ 10 mm; 53.8% PTB<32 weeks, 61.5% PTB<34 weeks, 92.3% PTB<37 weeks).

CONCLUSIONS

Asymptomatic twin pregnancies with a CL ≤ 10 mm had the shortest time interval to delivery and thus represent a specifically high risk group for sPTB. Although all patients were at high risk of sPTB, only one delivered within 1 or 2 weeks of presentation.

Recurrent Preterm Birth Reduction by 17-Hydroxyprogesterone Caproate in Dichorionic/Diamniotic Twin Gestation

OBJECTIVE

The study aimed to evaluate the impact of 17-hydroxyprogesterone caproate (17-OHPC) on recurrent preterm birth (PTB) in women with a prior PTB and a current dichorionic/diamniotic twin gestation.

STUDY DESIGN

We combined individual patient-level data from two prospective randomized placebo-controlled trials of prophylactic 17-OHPC in twin gestation and compared the rates of recurrent spontaneous PTB in those women with a prior singleton PTB randomized to placebo or 17-OHPC (250 mg weekly).

RESULTS

Only 7.4% of women with dichorionic/diamniotic twin gestation experienced a prior PTB. Among these 66 women, spontaneous delivery prior to 34 weeks occurred significantly less often (p = 0.03) in those randomized to 17-OHPC (20.6%) than in those randomized to placebo (46.9%). However, mean gestational length was not significantly different, and there was no statistically significant difference in composite neonatal outcome.

CONCLUSION

17-OHPC may be beneficial to women with a prior PTB and a current dichorionic/diamniotic twin gestation. These findings along with those reported by the Maternal Fetal Medicine Units Network in singletons suggest a common mechanism of action and a specific target population, those with a prior PTB, that may benefit from 17-OHPC treatment. A large prospective trial is needed to validate these findings.

KEY POINTS

· 17-OHPC reduces recurrent PTB in women with dichorionic/diamniotic twins.. · PTB risk and response to 17-OHPC may differ according to the type of twinning.. · 17-OHPC may affect a common pathway in twins and singletons with a prior PTB..

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.

New ultrasonographic midtrimester scoring method for predicting spontaneous preterm birth in uncomplicated asymptomatic twin pregnancies

OBJECTIVES

The aim of the present study was to evaluate a new ultrasonographic scoring method that could predict spontaneous preterm birth (sPTB) in uncomplicated twin pregnancies during routine anomaly screening in the midtrimester.

METHODS

This prospective study included women with a monochorionic diamniotic (MCDA) or dichorionic diamniotic (DCDA) twin pregnancy gestational ages from 17^0/7 through 22^6/7. A new ultrasonographic score between 0 and 5 points was calculated using cervical length (CL), uterocervical angle (UCA), and cervical dilatation status during routine anomaly screening in the midtrimester. The primary outcome of the study was the prediction of sPTB < 32 and <34 gestational weeks.

RESULTS

A total of 118 pregnant women with twins were evaluated, 31 of whom delivered before 34 gestational weeks an 87 of whom delivered after 34 gestational weeks. The sensitivity and specificity values were separately calculated for scores of 3.5 and 2.5 for predicting sPTB < 32 gestational weeks. The cut-off value of 3.5 provided a sensitivity of 80% and a specificity of 82%. When the score was 2.5, the sensitivity and specificity were 86 and 71%, respectively. To determine a score for predicting sPTB < 34 gestational week cut-off value of 3.5 provided a sensitivity of 80% and a specificity of 90%. When the score value was 2.5, the sensitivity and specificity of the method were 83 and 81%, respectively.

CONCLUSIONS

Our results indicated that the midtrimester new scoring is a simple technique that can be easily used as an improved tool for predicting the risk of sPTB in women with a twin pregnancy.

Preterm Labor: A Comprehensive Review of Guidelines on Diagnosis, Management, Prediction and Prevention

Importance

Preterm labor (PTL) is one of the most common and serious pregnancy complications associated with significant perinatal morbidity and mortality, as well as long-term neurologic impairment in the offspring.

Objective

The aim of this study was to review and compare the most recently published major guidelines on diagnosis, management, prediction, and prevention of this severe complication of pregnancy.

Evidence Acquisition

A descriptive review of guidelines from the National Institute for Health and Care Excellence (NICE), the World Health Organization, the American College of Obstetricians and Gynecologists, the New South Wales Government, and the European Association of Perinatal Medicine (EAPM) on PTL was carried out.

Results

There is a consensus among the reviewed guidelines that the diagnosis of PTL is based on clinical criteria, physical examination, measurement of cervical length (CL) with transvaginal ultrasound (TVUS) and use of biomarkers, although there is disagreement on the first-line diagnostic test. The NICE and the EAPM are in favor of TVUS CL measurement, whereas the New South Wales Government mentions that fetal fibronectin testing is the mainstay for PTL diagnosis. Moreover, there is consistency among the guidelines regarding the importance of treating PTL up to 34 weeks of gestation, to delay delivery for 48 hours, for the administration of antenatal corticosteroids, magnesium sulfate, and in utero transfer to higher care facility, although several discrepancies exist regarding the tocolytic drugs of choice and the administration of corticosteroids and magnesium sulfate after 34 and 30 gestational weeks, respectively. Routine cesarean delivery in case of PTL is unanimously not recommended. Finally, the NICE, the American College of Obstetricians and Gynecologists, and the EAPM highlight the significance of screening for PTL by TVUS CL measurement between 16 and 24 weeks of gestation and suggest the use of either vaginal progesterone or cervical cerclage for the prevention of PTL, based on specific indications. Cervical pessary is not recommended as a preventive measure.

Conclusions

Preterm labor is a significant contributor of perinatal morbidity and mortality with a substantial impact on health care systems. Thus, it seems of paramount importance to develop consistent international practice protocols for timely diagnosis and effective management of this major obstetric complication and subsequently improve pregnancy outcomes.

Interventions to Prevent Bronchopulmonary Dysplasia in Preterm Neonates: An Umbrella Review of Systematic Reviews and Meta-analyses

IMPORTANCE

Bronchopulmonary dysplasia (BPD) has multifactorial etiology and long-term adverse consequences. An umbrella review enables the evaluation of multiple proposed interventions for the prevention of BPD.

OBJECTIVE

To summarize and assess the certainty of evidence of interventions proposed to decrease the risk of BPD from published systematic reviews.

DATA SOURCES

MEDLINE, Cochrane Central Register of Controlled Trials, EMBASE, and Web of Science were searched from inception until November 9, 2020.

STUDY SELECTION

Meta-analyses of randomized clinical trials comparing interventions in preterm neonates that included BPD as an outcome.

DATA EXTRACTION AND SYNTHESIS

Data extraction was performed in duplicate. Quality of systematic reviews was evaluated using Assessment of Multiple Systematic Reviews version 2, and certainty of evidence was assessed using Grading of Recommendation, Assessment, Development, and Evaluation.

MAIN OUTCOMES AND MEASURES

(1) BPD or mortality at 36 weeks' postmenstrual age (PMA) and (2) BPD at 36 weeks' PMA.

RESULTS

A total of 154 systematic reviews evaluating 251 comparisons were included, of which 110 (71.4%) were high-quality systematic reviews. High certainty of evidence from high-quality systematic reviews indicated that delivery room continuous positive airway pressure compared with intubation with or without routine surfactant (relative risk [RR], 0.80 [95% CI, 0.68-0.94]), early selective surfactant compared with delayed selective surfactant (RR, 0.83 [95% CI, 0.75-0.91]), early inhaled corticosteroids (RR, 0.86 [95% CI, 0.75-0.99]), early systemic hydrocortisone (RR, 0.90 [95% CI, 0.82-0.99]), avoiding endotracheal tube placement with delivery room continuous positive airway pressure and use of less invasive surfactant administration (RR, 0.90 [95% CI, 0.82-0.99]), and volume-targeted compared with pressure-limited ventilation (RR, 0.73 [95% CI, 0.59-0.89]) were associated with decreased risk of BPD or mortality at 36 weeks' PMA. Moderate to high certainty of evidence showed that inhaled nitric oxide, lower saturation targets (85%-89%), and vitamin A supplementation are associated with decreased risk of BPD at 36 weeks' PMA but not the competing outcome of BPD or mortality, indicating they may be associated with increased mortality.

CONCLUSIONS AND RELEVANCE

A multipronged approach of delivery room continuous positive airway pressure, early selective surfactant administration with less invasive surfactant administration, early hydrocortisone prophylaxis in high-risk neonates, inhaled corticosteroids, and volume-targeted ventilation for preterm neonates requiring invasive ventilation may decrease the combined risk of BPD or mortality at 36 weeks' PMA.

A randomized controlled trial of two-doses of vaginal progesterone 400 vs. 200 mg for prevention of preterm labor in twin gestations

OBJECTIVES

To compare between the effectiveness and safety of two different daily doses of vaginal progesterone (400 vs. 200 mg) in the prevention of preterm labor in twin pregnancy.

METHODS

This is a prospective single-blinded randomized controlled trial conducted on 100 primi-gravida who had twin pregnancy and attended the antenatal clinic of a University hospital. They were equally and randomly allocated into two arms each containing 50 patients. Arm 1 received 400 mg and arm 2 received 200 mg vaginal progesterone daily at bed time starting from 14 weeks of pregnancy to 36 weeks. Transvaginal ultrasound was performed for assessment of the length of cervix at 14 and 22 weeks.

RESULTS

Both arms of the current study were comparable regarding the cervical length at 14 and 22 weeks, mean gestational age at delivery, incidence of pre-term delivery, birth weight of the first twin. Second twin in addition to the average weight of both twins. No statistical significance differences between two arms regarding incidence of early neonatal death. NICU, mechanical ventilation, length of admission in NICU for the first twin. Second twin as well as both twins.

CONCLUSIONS

Vaginal progesterone treatment with different doses was tolerable, but wasn't effective in the prevention of preterm labor in twin pregnancy.

Prevention of preterm birth in twin pregnancies

Twins represent 3.2% of all livebirth, however they account for 20% of all preterm deliveries, with 60% of then deliver before 37 weeks, and 10.7% before 32 weeks. Twin pregnancies have five times higher risk of early neonatal and infant death related to prematurity. Monochorionic twins have higher incidence of both indicated and spontaneous preterm delivery compared with dichorionic twins. Transvaginal cervical length before 24 weeks is the best tool to predict preterm birth, independent of other risk factors. Among all the evaluated therapies to decrease or prevent preterm birth in twin pregnancies, vaginal progesterone in women with transvaginal cervical length < 25mm decreased neonatal morbidity and physical exam indicated cerclage in women with cervical dilation > 1 cm have shown a significant decrease in preterm birth at different gestational ages and decreased perinatal mortality.

Prediction and Prevention of Spontaneous Preterm Birth: ACOG Practice Bulletin, Number 234

Preterm birth is among the most complex and important challenges in obstetrics. Despite decades of research and clinical advancement, approximately 1 in 10 newborns in the United States is born prematurely. These newborns account for approximately three-quarters of perinatal mortality and more than one half of long-term neonatal morbidity, at significant social and economic cost (1-3). Because preterm birth is the common endpoint for multiple pathophysiologic processes, detailed classification schemes for preterm birth phenotype and etiology have been proposed (4, 5). In general, approximately one half of preterm births follow spontaneous preterm labor, about a quarter follow preterm prelabor rupture of membranes (PPROM), and the remaining quarter of preterm births are intentional, medically indicated by maternal or fetal complications. There are pronounced racial disparities in the preterm birth rate in the United States. The purpose of this document is to describe the risk factors, screening methods, and treatments for preventing spontaneous preterm birth, and to review the evidence supporting their roles in clinical practice. This Practice Bulletin has been updated to include information on increasing rates of preterm birth in the United States, disparities in preterm birth rates, and approaches to screening and prevention strategies for patients at risk for spontaneous preterm birth.

Development and external validation of a nomogram for predicting preterm birth at < 32 weeks in twin pregnancy

The purpose of this study was to develop a dynamic model to predict the risk of spontaneous preterm birth at < 32 weeks in twin pregnancy. A retrospective clinical study of consecutively asymptomatic women with twin pregnancies from January 2017 to December 2019 in two tertiary medical centres was performed. Data from one centre were used to construct the model, and data from the other were used to evaluate the model. Data on maternal demographic characteristics, transvaginal cervical length and funnelling during 20-24 weeks were extracted. The prediction model was constructed with independent variables determined by multivariate logistic regression analyses. After applying specified exclusion criteria, an algorithm with maternal and biophysical factors was developed based on 88 twin pregnancies with a preterm birth < 32 weeks and 639 twin pregnancies with a delivery ≥ 32 weeks. It was then evaluated among 34 pregnancies with a preterm birth < 32 weeks and 252 pregnancies with a delivery ≥ 32 weeks in a second tertiary centre without specific training. The model reached a sensitivity of 80.00%, specificity of 88.17%, positive predictive value of 50.33% and negative predictive value of 96.71%; ROC characteristics proved that the model was superior to any single parameter with an AUC of 0.848 (all P < 0.005). We developed and validated a dynamic nomogram model to predict the individual probability of early preterm birth to better represent the complex aetiology of twin pregnancies and hopefully improve the prediction and indication of interventions.

The long-term effect of prenatal progesterone treatment on child development, behaviour and health: a systematic review

BACKGROUND

Progesterone is widely used in prenatal care. However, long-term effects of prenatal progesterone treatment on child development are unclear.

OBJECTIVES

To evaluate long-term outcomes in children after prenatal progesterone treatment.

SEARCH STRATEGY

MEDLINE, Embase and Cochrane Central Register of Controlled Trials from inception to 24 May 2020.

SELECTION CRITERIA

Randomised controlled trials (RCTs) reporting outcomes in children born to women who received progesterone treatment (compared with placebo or another intervention) during any trimester in pregnancy.

DATA COLLECTION AND ANALYSIS

Two authors independently selected and extracted data. We used the Cochrane Risk of Bias tool for randomised trials and Quality In Prognosis Studies.

MAIN RESULTS

Of 388 papers, we included seven articles based on five RCTs, comprising 4222 measurements of children aged 6 months to 8 years. All studies compared progesterone to placebo in second and/or third trimester for the prevention of preterm birth. Meta-analysis (two studies, n = 890 children) showed no difference in neurodevelopment as assessed by the Bayley-III Cognitive Composite score at 2 years between children exposed to progesterone versus placebo (Standardised Mean Difference -0.04, 95% Confidence Interval -0.26 to 0.19), I2  = 22%. Heterogeneity prohibited additional meta-analyses. Other long-term outcomes showed no differences.

CONCLUSIONS

Our systematic review comprising a multitude of developmental measurements with a broad age range did not find evidence of benefit or harm in offspring prenatally exposed to progesterone treatment for the prevention of preterm birth. We identified an urgent need for follow-up studies of prenatal progesterone administration in early pregnancy and effects in offspring beyond early childhood.

TWEETABLE ABSTRACT

Progesterone to prevent preterm birth: no effect on child development. Outcomes after first trimester progesterone are unclear.

Prevention of preterm birth in multiples

PURPOSE OF REVIEW

Multifetal pregnancy carries increased risk of preterm delivery, and consensus on management options to prevent early birth in this population has not been reached. This review serves to summarize the most contemporary findings on this controversial topic.

RECENT FINDINGS

Examination-indicated cerclage is effective in reducing preterm birth in twin pregnancies, whereas cerclages for other indications are less convincing. Cervical pessary may be beneficial for patients with a short cervix and in those who have had threatened preterm labor. Progesterone supplementation for multifetal gestation alone is not beneficial, but it can be considered in those with a history of prior singleton preterm birth.

SUMMARY

Interventions for preterm birth prevention in multiple gestations remain under investigation, and further data is required in order to reach consensus for this high-risk population.

Evaluating Progestogens for Preventing Preterm birth International Collaborative (EPPPIC): meta-analysis of individual participant data from randomised controlled trials

BACKGROUND

Preterm birth is a global health priority. Using a progestogen during high-risk pregnancy could reduce preterm birth and adverse neonatal outcomes.

METHODS

We did a systematic review of randomised trials comparing vaginal progesterone, intramuscular 17-hydroxyprogesterone caproate (17-OHPC), or oral progesterone with control, or with each other, in asymptomatic women at risk of preterm birth. We identified published and unpublished trials that completed primary data collection before July 30, 2016, (12 months before data collection began), by searching MEDLINE, Embase, CINAHL, the Maternity and Infant Care Database, and relevant trial registers between inception and July 30, 2019. Trials of progestogen to prevent early miscarriage or immediately-threatened preterm birth were excluded. Individual participant data were requested from investigators of eligible trials. Outcomes included preterm birth, early preterm birth, and mid-trimester birth. Adverse neonatal sequelae associated with early births were assessed using a composite of serious neonatal complications, and individually. Adverse maternal outcomes were investigated as a composite and individually. Individual participant data were checked and risk of bias assessed independently by two researchers. Primary meta-analyses used one-stage generalised linear mixed models that incorporated random effects to allow for heterogeneity across trials. This meta-analysis is registered with PROSPERO, CRD42017068299.

FINDINGS

Initial searches identified 47 eligible trials. Individual participant data were available for 30 of these trials. An additional trial was later included in a targeted update. Data were therefore available from a total of 31 trials (11 644 women and 16185 offspring). Trials in singleton pregnancies included mostly women with previous spontaneous preterm birth or short cervix. Preterm birth before 34 weeks was reduced in such women who received vaginal progesterone (nine trials, 3769 women; relative risk [RR] 0·78, 95% CI 0·68-0·90), 17-OHPC (five trials, 3053 women; 0·83, 0·68-1·01), and oral progesterone (two trials, 181 women; 0·60, 0·40-0·90). Results for other birth and neonatal outcomes were consistently favourable, but less certain. A possible increase in maternal complications was suggested, but this was uncertain. We identified no consistent evidence of treatment interaction with any participant characteristics examined, although analyses within subpopulations questioned efficacy in women who did not have a short cervix. Trials in multifetal pregnancies mostly included women without additional risk factors. For twins, vaginal progesterone did not reduce preterm birth before 34 weeks (eight trials, 2046 women: RR 1·01, 95% CI 0·84-1·20) nor did 17-OHPC for twins or triplets (eight trials, 2253 women: 1·04, 0·92-1·18). Preterm premature rupture of membranes was increased with 17-OHPC exposure in multifetal gestations (rupture <34 weeks RR 1·59, 95% CI 1·15-2·22), but we found no consistent evidence of benefit or harm for other outcomes with either vaginal progesterone or 17-OHPC.

INTERPRETATION

Vaginal progesterone and 17-OHPC both reduced birth before 34 weeks' gestation in high-risk singleton pregnancies. Given increased underlying risk, absolute risk reduction is greater for women with a short cervix, hence treatment might be most useful for these women. Evidence for oral progesterone is insufficient to support its use. Shared decision making with woman with high-risk singleton pregnancies should discuss an individual's risk, potential benefits, harms and practicalities of intervention. Treatment of unselected multifetal pregnancies with a progestogen is not supported by the evidence.

FUNDING

Patient-Centered Outcomes Research Institute.

Uterocervical angle at 20 weeks: A promising predictor of spontaneous preterm birth in twin pregnancies

OBJECTIVE

To compare the performance of uterocervical angle (UCA) and cervical length (CL) measurement at 20 weeks of pregnancy for prediction of spontaneous preterm birth (sPTB) in twin pregnancies.

STUDY DESIGN

We conducted a retrospective cohort study of 424 twin pregnancies who delivered in our center from October 2014 to December 2018 and who underwent transvaginal ultrasound between 19⁺⁰-22⁺⁰ weeks to measure CL during routine second trimester scan. Recorded ultrasound images of CL were reassessed to evaluate UCA. Medical and obstetric data were also collected for statistical analysis.

RESULTS

A total of 424 women were included. The rates of sPTB rate below 28, 32 and 34 weeks of gestation were 2.8 %, 5.4 % and 10.4 %, respectively. ROC curves showed a better area under the curve (AUC) for UCA at all gestational ages compared with CL (AUC for sPTB <28 weeks 0.902 (p < 0.001) vs 0.620 (p 0.175); AUC for sPTB <32 weeks 0.740 (p 0.001) vs 0.620 (p 0.058); AUC for sPTB <34 weeks 0.676 (p 0.001) vs 0.632 (p 0.047). UCA > 120 degrees was significantly associated with sPTB <28 weeks (p < 0.001; OR 39.17; CI 4.81-319.23; NPV, 99.65 %), <32 weeks (OR 4.23; p 0.002) and <34 weeks of gestation (OR 2.66; p 0.01).

CONCLUSION

In our study, an UCA > 120 degrees allowed to identify those women with twin pregnancies at risk of sPTB and performed better than CL measurement.

Early vaginal progesterone versus placebo in twin pregnancies for the prevention of spontaneous preterm birth: a randomized, double-blind trial

BACKGROUND

In women with a singleton pregnancy and sonographic short cervix in midgestation, vaginal administration of progesterone reduces the risk of early preterm birth and improves neonatal outcomes without any demonstrable deleterious effects on childhood neurodevelopment. In women with twin pregnancies, the rate of spontaneous early preterm birth is 10 times higher than that in singletons, and in this respect, all twins are at an increased risk of preterm birth. However, 6 trials in unselected twin pregnancies reported that vaginal administration of progesterone from midgestation had no significant effect on the incidence of early preterm birth. Such apparent lack of effectiveness of progesterone in twins may be due to inadequate dosage or treatment that is started too late in pregnancy.

OBJECTIVE

The early vaginal progesterone for the prevention of spontaneous preterm birth in twins, a randomized, placebo-controlled, double-blind trial, was designed to test the hypothesis that among women with twin pregnancies, vaginal progesterone at a dose of 600 mg per day from 11 to 14 until 34 weeks' gestation, as compared with placebo, would result in a significant reduction in the incidence of spontaneous preterm birth between 24⁺⁰ and 33⁺⁶ weeks.

STUDY DESIGN

The trial was conducted at 22 hospitals in England, Spain, Bulgaria, Italy, Belgium, and France. Women were randomly assigned in a 1:1 ratio to receive either progesterone or placebo, and in the random-sequence generation, there was stratification according to the participating center. The primary outcome was spontaneous birth between 24⁺⁰ and 33⁺⁶ weeks' gestation. Statistical analyses were performed on an intention-to-treat basis. Logistic regression analysis was used to determine the significance of difference in the incidence of spontaneous birth between 24⁺⁰ and 33⁺⁶ weeks' gestation between the progesterone and placebo groups, adjusting for the effect of participating center, chorionicity, parity, and method of conception. Prespecified tests of treatment interaction effects with chorionicity, parity, method of conception, compliance, and cervical length at recruitment were performed. A post hoc analysis using mixed-effects Cox regression was used for further exploration of the effect of progesterone on preterm birth.

RESULTS

We recruited 1194 women between May 2017 and April 2019; 21 withdrew consent and 4 were lost to follow-up, which left 582 in the progesterone group and 587 in the placebo group. Adherence was good, with reported intake of ≥80% of the required number of capsules in 81.4% of the participants. After excluding births before 24 weeks and indicated deliveries before 34 weeks, spontaneous birth between 24⁺⁰ and 33⁺⁶ weeks occurred in 10.4% (56/541) of participants in the progesterone group and in 8.2% (44/538) in the placebo group (odds ratio in the progesterone group, adjusting for the effect of participating center, chorionicity, parity, and method of conception, 1.35; 95% confidence interval, 0.88-2.05; P=.17). There was no evidence of interaction between the effects of treatment and chorionicity (P=.28), parity (P=.35), method of conception (P=.56), and adherence (P=.34); however, there was weak evidence of an interaction with cervical length (P=.08) suggestive of harm to those with a cervical length of ≥30 mm (odds ratio, 1.61; 95% confidence interval, 1.01-2.59) and potential benefit for those with a cervical length of <30 mm (odds ratio, 0.56; 95% confidence interval, 0.20-1.60). There was no evidence of difference between the 2 treatment groups for stillbirth or neonatal death, neonatal complications, neonatal therapy, and poor fetal growth. In the progesterone group, 1.4% (8/582) of women and 1.9% (22/1164) of fetuses experienced at least 1 serious adverse event; the respective numbers for the placebo group were 1.2% (7/587) and 3.2% (37/1174) (P=.80 and P=.06, respectively). In the post hoc time-to-event analysis, miscarriage or spontaneous preterm birth between randomization and 31⁺⁶ weeks' gestation was reduced in the progesterone group relative to the placebo group (hazard ratio, 0.23; 95% confidence interval, 0.08-0.69).

CONCLUSION

In women with twin pregnancies, universal treatment with vaginal progesterone did not reduce the incidence of spontaneous birth between 24⁺⁰ and 33⁺⁶ weeks' gestation. Post hoc time-to-event analysis led to the suggestion that progesterone may reduce the risk of spontaneous birth before 32 weeks' gestation in women with a cervical length of <30 mm, and it may increase the risk for those with a cervical length of ≥30 mm.

Two-stage nomogram models in mid-gestation for predicting the risk of spontaneous preterm birth in twin pregnancy

PURPOSE

This study aimed to develop two-stage nomogram models to predict individual risk of preterm birth at < 34 weeks of gestation in twin pregnancies by incorporating clinical characteristics at mid-gestation.

METHODS

We used a case-control study design of women with twin pregnancies followed up in a tertiary medical centre from January 2018 to March 2019. Maternal demographic characteristics and transvaginal cervical length data were extracted. The nomogram models were constructed with independent variables determined by multivariate logistic regression analyses. The risk score was calculated based on the nomogram models.

RESULTS

In total, 65 twin preterm birth cases (< 34 weeks) and 244 controls met the inclusion criteria. Based on univariate and multivariate logistic regression analyses, we built two-stage nomogram prediction models with satisfactory discrimination and calibration when applied to the validation sets (first-stage [22-24 weeks] prediction model, C-index: 0.805 and 0.870, respectively; second-stage [26-28 weeks] prediction model, C-index: 0.847 and 0.908, respectively). Restricted cubic splines graphically showed the risk of preterm birth among individuals with increased risk scores. Moreover, the decision curve analysis indicated that both prediction models show positive clinical benefit.

CONCLUSION

We developed and validated two-stage nomogram models at mid-gestation to predict the individual probability of preterm birth at < 34 weeks in twin pregnancy.

Cervical pessary to prevent preterm birth in asymptomatic high-risk women: a systematic review and meta-analysis

BACKGROUND

Randomized controlled trials that have assessed the efficacy of cervical pessary to prevent preterm birth in asymptomatic high-risk women have reported conflicting results.

OBJECTIVE

To evaluate the efficacy and safety of cervical pessary to prevent preterm birth and adverse perinatal outcomes in asymptomatic high-risk women.

DATA SOURCES

MEDLINE, EMBASE, POPLINE, CINAHL, and LILACS (from their inception to October 31, 2019), Cochrane databases, Google Scholar, bibliographies, and conference proceedings.

STUDY ELIGIBILITY CRITERIA

Randomized controlled trials that compared cervical pessary with standard care (no pessary) or alternative interventions in asymptomatic women at high risk for preterm birth.

STUDY APPRAISAL AND SYNTHESIS METHODS

The systematic review was conducted according to the Cochrane Handbook guidelines. The primary outcome was spontaneous preterm birth <34 weeks of gestation. Secondary outcomes included adverse pregnancy, maternal, and perinatal outcomes. Pooled relative risks with 95% confidence intervals were calculated. Quality of evidence was assessed using the GRADE methodology.

RESULTS

Twelve studies (4687 women and 7167 fetuses/infants) met the inclusion criteria: 8 evaluated pessary vs no pessary in women with a short cervix, 2 assessed pessary vs no pessary in unselected multiple gestations, and 2 compared pessary vs vaginal progesterone in women with a short cervix. There were no significant differences between the pessary and no pessary groups in the risk of spontaneous preterm birth <34 weeks of gestation among singleton gestations with a cervical length ≤25 mm (relative risk, 0.80; 95% confidence interval, 0.43-1.49; 6 trials, 1982 women; low-quality evidence), unselected twin gestations (relative risk, 1.05; 95% confidence interval, 0.79-1.41; 1 trial, 1177 women; moderate-quality evidence), twin gestations with a cervical length <38 mm (relative risk, 0.75; 95% confidence interval, 0.41-1.36; 3 trials, 1128 women; low-quality evidence), and twin gestations with a cervical length ≤25 mm (relative risk; 0.72, 95% confidence interval, 0.25-2.06; 2 trials, 348 women; low-quality evidence). Overall, no significant differences were observed between the pessary and no pessary groups in preterm birth <37, <32, and <28 weeks of gestation, and most adverse pregnancy, maternal, and perinatal outcomes (low- to moderate-quality evidence for most outcomes). There were no significant differences in the risk of spontaneous preterm birth <34 weeks of gestation between pessary and vaginal progesterone in singleton gestations with a cervical length ≤25 mm (relative risk, 0.99; 95% confidence interval, 0.54-1.83; 1 trial, 246 women; low-quality evidence) and twin gestations with a cervical length <38 mm (relative risk, 0.73; 95% confidence interval, 0.46-1.18; 1 trial, 297 women; very low-quality evidence). Vaginal discharge was significantly more frequent in the pessary group than in the no pessary and vaginal progesterone groups (relative risks, ∼2.20; high-quality evidence).

CONCLUSION

Current evidence does not support the use of cervical pessary to prevent preterm birth or to improve perinatal outcomes in singleton or twin gestations with a short cervix and in unselected twin gestations.

Effectiveness of cervical pessary compared to cervical cerclage with or without vaginal progesterone for the prevention of preterm birth in women with twin pregnancies and a short cervix: study protocol for a two-by-two factorial randomised clinical trial

INTRODUCTION

Women with twin pregnancies and a short cervix are at increased risk for preterm birth (PTB). Given the burden of prematurity and its attendant risks, the quest for effective interventions in twins has been an area of considerable research. Studies investigating the effectiveness of cervical cerclage, cervical pessary and vaginal progesterone in preventing PTB have yielded conflicting results. The aim of this study is to compare the effectiveness of cervical pessary and cervical cerclage with or without vaginal progesterone to prevent PTB in women with twin pregnancies and a cervical length (CL) ≤ 28 mm.

METHODS AND ANALYSIS

This multicentre, randomised clinical trial will be conducted at My Duc Hospital and My Duc Phu Nhuan Hospital, Vietnam. Asymptomatic women with twin pregnancies and a CL ≤28 mm, measured at 16-22 weeks' gestation, will be randomised in a 1:1:1:1 ratio to receive a cerclage, pessary, cerclage plus progesterone or pessary plus progesterone. Primary outcome will be PTB <34 weeks. Secondary outcomes will be maternal and neonatal complications. We preplanned a subgroup analysis according to CL from all women after randomisation and divided into four quartiles. Analysis will be conducted on an intention-to-treat basis. The rate of PTB <34 weeks' gestation in women with twin pregnancies and a cervix ≤28 mm and treated with pessary in our previous study at My Duc Hospital was 24.2%. A sample size of 340 women will be required to show or refute that cervical cerclage decreases the rate of PTB <34 weeks by 50% compared with pessary (from 24.2% to 12.1%, α level 0.05, power 80%, 5% lost to follow-up and protocol deviation). This study is not to be powered to assess interactions between interventions.

ETHICS AND DISSEMINATION

Ethical approval was obtained from the Institutional Ethics Committee of My Duc Hospital and informed patient consent was obtained before study enrolment. Results of the study will be submitted for publication in a peer-reviewed journal.

TRIAL REGISTRATION NUMBER

NCT03863613 (date of registration: 4 March 2019).

The effect of early administration of rectal progesterone in IVF/ICSI twin pregnancies on the preterm birth rate: a randomized trial

BACKGROUND

The rate of multiple pregnancies in IVF/ICSI ranges from 20 to 30%. The incidence of preterm birth in multiple pregnancies is as high as 60% and is even higher in pregnancies conceived after IVF & ICSI. The effect of progesterone on prevention of preterm birth in twins is controversial. Our group has proven a positive effect in reduction of preterm birth, by starting progesterone from the mid-trimester, in exclusively IVF/ICSI singleton pregnancies but not twins. The purpose of our current study was to explore the effect of earlier administration of natural progesterone, in IVF/ICSI twin pregnancies starting at 11-14 weeks for prevention of preterm birth.

METHODS

This is a double-blind, placebo controlled, single center, randomized clinical trial. Women with dichorionic twin gestations, having an IVF/ICSI trial were randomized to receive natural rectal progesterone (800 mg daily) vs placebo, starting early from 11 to 14 weeks. They also received oral and vaginal antimicrobial agents as part of our routine treatment for vaginitis and urinary tract infection. They were randomized regardless of cervical length and had no previous history of preterm birth or known Mullerian anomalies. The primary outcome was spontaneous preterm birth rate before 37 weeks. The secondary outcome was; spontaneous preterm birth before 34, 32, 28 weeks and neonatal outcome.

RESULTS

A total of 203 women were randomized to both groups, final analysis included 199 women as 4 were lost to follow up. The base line characteristics as well as gestational age at delivery were not significantly different between the study and the placebo group (34.7 ± 3.6 vs 34.5 ± 4.5, P = 0.626). Progesterone administration was not associated with a significant decrease in the spontaneous preterm birth rates before 37 weeks (73.5% vs 68%, P = 0.551), before 34 (20.6% vs 21.6%, P = 0.649), before 32 (8.8% vs 12.4%, P = 0.46) & before 28 (4.9% vs 3.1%, P = 0.555) weeks.

CONCLUSIONS

Rectal natural progesterone starting from the first trimester in IVF/ICSI twin pregnancies did not reduce spontaneous preterm birth.

TRIAL REGISTRATION

The trial was registered on 31 January 2014 at www.ISRCTN.com, number 69810120.

Uterocervical angle as a predictor of spontaneous preterm birth in twin pregnancies

Objective: To assess the ability of uterocervical angle (UCA) compared with cervical length (CL) to predict the risk of spontaneous preterm birth (sPTB) in twin pregnancies and its performance when it was included in a combined predictive model of clinical and ultrasonographic parameters.Methods: We conducted a retrospective cohort study of twin pregnancies undergoing transvaginal ultrasound between 19⁺⁰-21⁺⁶ weeks to measure CL during routine second trimester scan from January 2015 through December 2016. Recorded ultrasound images of CL were reassessed to evaluate UCA. Medical and obstetric data were also collected for statistical analysis. A logistic regression model was created for predicting sPTB including UCA and other variables.Results: A total of 177 women were included. The rates of sPTB rate below 28, 32 and 34 weeks of gestation were 4.5%, 6.8% and 12.4%, respectively. ROC curves showed a better area under the curve (AUC) for UCA at all gestational ages compared with CL (AUC for sPTB <28 weeks 0.840 (p = .005) vs 0.627 (p = .388); AUC for sPTB <32 weeks 0.706 (p = .022) vs 0.619 (p = .255); AUC for sPTB <34 weeks 0.674 (p = .008) vs 0.568 (p = .344). UCA >117 degrees was significantly associated with sPTB <28 weeks (p = .002; OR 15.3; CI 1.66-142.37; NPV, 99.2%), <32 weeks (OR 3.84; p = .031) and <34 weeks of gestation (OR 3.10; p = .016). Based on multivariate analyses, the best predictive model included uterocervical angle (p = .032), cervical length (p = .002) and maternal height (p = .001) (Nagelkerke R² 0.944).Conclusion: In our study, an UCA > 117 degrees allowed to identify those women with twin pregnancies at risk of sPTB and performed better than CL measurement. Our combined prediction model was able to adequately predict the risk of sPTB in the twin pregnancies of our research.

Intramuscular progesterone in women with twins and a prior singleton spontaneous preterm birth

BACKGROUND

Although the use of 17-alpha-hydroxyprogesterone caproate is one of the most commonly used strategies to reduce the risk of preterm birth since its approval by the Food and Drug Administration in 2011, there has been controversy recently that there may be no benefit associated with its use in singleton pregnancies in women with a prior history of spontaneous preterm birth. However, very few of these investigations evaluated the use of intramuscular progesterone in twin pregnancies. A few studies that used 17-alpha-hydroxyprogesterone caproate in twin pregnancies had mainly included unselected twin pregnancies. Although a twin pregnancy is independently associated with an increased likelihood of preterm birth, the primary indication for the use of supplemental progesterone in pregnancy is prior history of spontaneous preterm birth. Therefore, our investigation of weekly intramuscular progesterone in twin pregnancies with this birth history best addresses this question using a selected cohort.

OBJECTIVE

To assess whether weekly 17-alpha-hydroxyprogesterone caproate prevents recurrent preterm birth in women with a current twin pregnancy and a prior singleton spontaneous preterm birth.

STUDY DESIGN

This was a retrospective cohort study of women with twin pregnancy and a prior singleton spontaneous preterm birth in 2 institutions between January 2005 and December 2016. One group (intervention group) consisted of women who received weekly 17-alpha-hydroxyprogesterone caproate, whereas the other (control group) did not. The primary outcome was twin spontaneous preterm birth <34 weeks compared with odds ratio and adjusted odds ratio, adjusting for potential confounders. Secondary outcomes included composite neonatal morbidity such as respiratory distress syndrome, intraventricular hemorrhage, necrotizing enterocolitis, admission to the neonatal intensive care nursery, and fetal or neonatal death before hospital discharge.

RESULTS

A total of 79 patients were included; 27 women received weekly 17-alpha-hydroxyprogesterone caproate and 52 did not. There were no statistically significant differences in maternal demographics except for age. Spontaneous preterm birth <34 weeks occurred in 16 patients (59%) in the intervention group vs 24 (46%) in the control group (odds ratio, 1.69; 95% confidence interval, 0.68-4.54). Composite neonatal morbidity occurred in 20 pregnancies (74%) in the intervention group and 41 pregnancies (79%) in the control group (odds ratio, 0.76; 95% confidence interval, 0.27-2.12). There remained no differences in outcomes after adjusting for potential confounders.

CONCLUSION

In our study, weekly 17-alpha-hydroxyprogesterone caproate did not prevent spontaneous preterm birth or neonatal morbidity in women with twins and a prior singleton spontaneous preterm birth; however, further research with larger numbers and prospective design is needed.

The use of progesterone during pregnancy to prevent preterm birth

One of the most significant problems facing maternal and children health worldwide is preterm birth (PTB). Although strategies to increase the survival of premature infants have significantly improved in the past few decades, they have yet to be successful. Nine years ago, the use of progesterone in pregnancy was approved by the United States Food and Drug Administration (FDA) for PTB prevention. This paper reviews the recent evidence supporting the use of progesterone in pregnancy for PTB prevention and provides guidelines for its use in daily clinical practice. The guidelines address multiple current controversial areas regarding the prevention of PTB to aid physicians with their clinical decision-making practice, including the use in multifetal gestation, different formulations, safety in pregnancy, dose and route of administration.Saudi Med J 2020; Vol. 41 (4): 333-340doi: 10.15537/smj.2020.4.25036How to cite this article:Alsulmi ES, Alfaraj M, Faden Y, Al Qahtani N. The use of progesterone during pregnancy to prevent preterm birth. Saudi Med J 2020; Vol. 41: 333-340. doi: 10.15537/smj.2020.4.25036.

Cervical pessary vs vaginal progesterone for prevention of preterm birth in women with twin pregnancy and short cervix: economic analysis following randomized controlled trial

OBJECTIVE

To compare the cost-effectiveness of cervical pessary vs vaginal progesterone to prevent preterm birth and neonatal morbidity in women with twin pregnancy and a short cervix.

METHODS

Between 4 March 2016 and 3 June 2017, we performed this economic analysis following a randomized controlled trial (RCT), performed at My Duc Hospital, Ho Chi Minh City, Vietnam, that compared cervical pessary to vaginal progesterone in women with twin pregnancy and cervical length < 38 mm between 16 and 22 weeks of gestation. We used morbidity-free neonatal survival as a measure of effectiveness. Data on pregnancy outcome, maternal morbidity and neonatal complications were collected prospectively from medical files; additional information was obtained via telephone interviews with the patients. The incremental cost-effectiveness ratio was calculated as the incremental cost required to achieve one extra surviving morbidity-free neonate in the pessary group compared with in the progesterone group. Probabilistic and one-way sensitivity analyses were also performed.

RESULTS

During the study period, we screened 1113 women with twin pregnancy, of whom 300 fulfilled the inclusion criteria of the RCT and gave informed consent to participate. These women were assigned randomly to receive cervical pessary (n = 150) or vaginal progesterone (n = 150), with two women and one woman, respectively, being lost to follow-up. The rate of morbidity-free neonatal survival was significantly higher in the pessary group compared with the progesterone group (n = 241/296 (81.4%) vs 219/298 (73.5%); relative risk, 1.11 (95% CI, 1.02-1.21), P = 0.02). The mean total cost per woman was 3146 € in the pessary group vs 3570 € in the progesterone group (absolute difference, -424 € (95% CI, -842 to -3 €), P = 0.048). The cost per morbidity-free neonate was significantly lower in the pessary group compared with that in the progesterone group (2492 vs 2639 €; absolute difference, -147 € (95% CI, -284 to 10 €), P = 0.035).

CONCLUSION

In women with twin pregnancy and a short cervix, cervical pessary improves significantly the rate of morbidity-free neonatal survival while reducing costs, as compared with vaginal progesterone. Copyright © 2019 ISUOG. Published by John Wiley & Sons Ltd.

Pessary Compared With Vaginal Progesterone for the Prevention of Preterm Birth in Women With Twin Pregnancies and Cervical Length Less Than 38 mm: A Randomized Controlled Trial

OBJECTIVE

To compare the effectiveness of cervical pessary to vaginal progesterone for the prevention of preterm birth in women with twin pregnancies and short cervix.

METHODS

This randomized controlled trial was conducted at My Duc Hospital, Vietnam. Asymptomatic women with twin pregnancies and cervical length less than 38 mm were randomized to Arabin pessary or vaginal progesterone (400 mg once a day) group. The primary outcome was preterm birth at less than 34 weeks of gestation. Secondary outcomes were adverse maternal and perinatal complications. We planned a subgroup analysis according to quartile of cervical length. Analysis was conducted on an intention-to-treat basis. We estimated that the primary outcome would occur in 28.4% of women treated with progesterone. Thus a total sample size of 290 women divided equally into two groups was required to detect a 14% absolute risk difference in the primary outcome between the two groups (power 80%, alpha-error 5%, 10% loss to follow-up).

RESULTS

Between March 2016 and June 2017, we randomized 300 women, 150 women in each group. Preterm birth at less than 34 weeks of gestation occurred in 24 (16%) women in the pessary group and 33 (22%) women in the progesterone group (relative risk [RR] 0.73, 95% CI 0.46-1.18). The use of pessary significantly reduced the composite of poor perinatal outcomes (19% vs 27%; RR 0.70, 95% CI 0.43-0.93). In women with cervical length of 28 mm or less (25th percentile), pessary significantly reduced the preterm birth rate at less than 34 weeks of gestation from 46% (16/35) to 21% (10/47) (RR 0.47, 95% CI 0.24-0.90) and significantly improved the composite of poor perinatal outcomes.

CONCLUSION

Cervical pessary and 400 mg vaginal progesterone resulted in similar rates of preterm birth at less than 34 weeks of gestation in women with twin pregnancies and cervical length less than 38 mm.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov, NCT02623881.

Prenatal administration of progestogens for preventing spontaneous preterm birth in women with a multiple pregnancy

BACKGROUND

Multiple pregnancy is a strong risk factor for preterm birth, and more than 50% of women with a twin pregnancy will give birth prior to 37 weeks' gestation. Infants born preterm are recognised to be at increased risk of many adverse health outcomes, contributing to more than half of overall perinatal mortality. Progesterone is produced naturally in the body and has a role in maintaining pregnancy, although it is not clear whether administering progestogens to women with multiple pregnancy at high risk of early birth is effective and safe. Since publication of this new review in Issue 10, 2017, we have now moved one study (El-Refaie 2016) from included to studies awaiting classification, pending clarification about the study data.

OBJECTIVES

To assess the benefits and harms of progesterone administration for the prevention of preterm birth in women with a multiple pregnancy.

SEARCH METHODS

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register, ClinicalTrials.gov, the WHO International Clinical Trials Registry Platform (ICTRP) (1 November 2016) and reference lists of retrieved studies.

SELECTION CRITERIA

We included randomised controlled trials examining the administration of a progestogen by any route for the prevention of preterm birth in women with multiple pregnancy. We did not include quasi-randomised or cross-over studies.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed reports identified by the search for eligibility, extracted data, assessed risk of bias and graded the quality of the evidence.

MAIN RESULTS

We included 16 trials, which all compared either vaginal or intramuscular (IM) progesterone with a placebo or no treatment, and involved a total of 4548 women. The risk of bias for the majority of included studies was low, with the exception of three studies that had inadequate blinding, or significant loss to follow-up or both, or were not reported well enough for us to make a judgement. We graded the evidence low to high quality, with downgrading for statistical heterogeneity, design limitations in some of the studies contributing data, and imprecision of the effect estimate. 1 IM progesterone versus no treatment or placebo More women delivered at less than 34 weeks' gestation in the IM progesterone group compared with placebo (risk ratio (RR) 1.54, 95% confidence interval (CI) 1.06 to 2.26; women = 399; studies = 2; low-quality evidence). Although the incidence of perinatal death in the progesterone group was higher, there was considerable uncertainty around the effect estimate and high heterogeneity between studies (average RR 1.45, 95% CI 0.60 to 3.51; infants = 3089; studies = 6; I2 = 71%; low-quality evidence). No studies reported maternal mortality or major neurodevelopmental disability at childhood follow-up. There were no clear group differences found in any of the other maternal or infant outcomes (preterm birth less than 37 weeks (RR 1.05, 95% CI 0.98 to 1.13; women = 2010; studies = 5; high-quality evidence); preterm birth less than 28 weeks (RR 1.08, 95% CI 0.75 to 1.55; women = 1920; studies = 5; moderate-quality evidence); infant birthweight less than 2500 g (RR 0.99, 95% CI 0.90 to 1.08; infants = 4071; studies = 5; I2 = 76%, moderate-quality evidence)). No childhood outcomes were reported in the trials. 2 Vaginal progesterone versus no treatment or placebo by dose There were no clear group differences in incidence of preterm birth before 34 weeks (average RR 0.90, 95% CI 0.66 to 1.23; women = 1503; studies = 5; I2 = 36%; low-quality evidence). Although fewer births before 34 weeks appeared to occur in the progesterone group, the CIs crossed the line of no effect. Incidence of perinatal death was higher in the progesterone group, although there was considerable uncertainty in the effect estimate and the quality of the evidence was low for this outcome (RR 1.23, 95% CI 0.74 to 2.06; infants = 2287; studies = 3; low-quality evidence). No studies reported maternal mortality or major neurodevelopmental disability at childhood follow-up. There were no clear group differences found in any of the other maternal or infant outcomes (preterm birth less than 37 weeks (average RR 0.97, 95% CI 0.89 to 1.06; women = 1597; studies = 6; moderate-quality evidence); preterm birth less than 28 weeks (RR 1.53, 95% CI 0.79 to 2.97; women = 1345; studies = 3; low-quality evidence); infant birthweight less than 2500 g (average RR 0.95, 95% CI 0.84 to 1.07; infants = 2640; studies = 3; I2 = 66%, moderate-quality evidence)). No childhood outcomes were reported in the trials. For secondary outcomes, there were no clear group differences found in any of the other maternal outcomes except for caesarean section, where women who received vaginal progesterone did not have as many caesarean sections as those in the placebo group, although the difference between groups was not large (8%) (RR 0.92, 95% CI 0.86 to 0.98; women = 1919; studies = 5; I2 = 0%). There were no clear group differences found in any of the infant outcomes except for mechanical ventilation, which was required by fewer infants whose mothers had received the vaginal progesterone (RR 0.70, 95% CI 0.52 to 0.94; infants = 2695; studies = 4).

AUTHORS' CONCLUSIONS

Overall, for women with a multiple pregnancy, the administration of progesterone (either IM or vaginal) does not appear to be associated with a reduction in risk of preterm birth or improved neonatal outcomes. Future research could focus on a comprehensive individual participant data meta-analysis including all of the available data relating to both IM and vaginal progesterone administration in women with a multiple pregnancy, before considering the need to conduct trials in subgroups of high-risk women (for example, women with a multiple pregnancy and a short cervical length identified on ultrasound).

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.

Progesterone-Related Immune Modulation of Pregnancy and Labor

Pregnancy involves a complex interplay between maternal neuroendocrine and immunological systems in order to establish and sustain a growing fetus. It is thought that the uterus at pregnancy transitions from quiescent to laboring state in response to interactions between maternal and fetal systems at least partly via altered neuroendocrine signaling. Progesterone (P4) is a vital hormone in maternal reproductive tissues and immune cells during pregnancy. As such, P4 is widely used in clinical interventions to improve the chance of embryo implantation, as well as reduce the risk of miscarriage and premature labor. Here we review research to date that focus on the pathways through which P4 mediates its actions on both the maternal reproductive and immune system. We will dissect the role of P4 as a modulator of inflammation, both systemic and intrinsic to the uterus, during human pregnancy and labor.

[Effectiveness of preventive cervical cerclage to prevent preterm birth in women with twin gestation with obstetrical history of late pregnancy loss or preterm birth]

OBJECTIVES

Evaluate the effectiveness of preventive cervical cerclage for twin pregnancy with obstetrical history.

METHODS

Through this retrospective cohort study, subjects exposed between 2002 and 2017 were compared with unexposed ones. All patients who had twin pregnancy with at least one previous late pregnancy loss or prematurity before 34SA were included. Two groups were compared: "preventive cerclage" versus "no preventive cerclage". The outcome was the prematurity before 34 gestation weeks (GW) rate.

RESULTS

Among 1972 twin pregnancies registered between 2002 and 2017, 69 (3.5%) patients with at least one previous late pregnancy loss or prematurity before 34 GW, were part of the study. There were 20 (29.0%) women in the group "preventive cerclage" and 49 (71.0%) women in the group "no preventive cerclage". Women in the "preventive cerclage" group had poorer obstetrical history. The rate of prematurity before 34GW was not significantly different between these both groups (45.0% versus 44.9%; P=0.99, crude OR: 1.00 (0.35-2.83), adjusted OR: 1.06 (0.33-3.44)).

CONCLUSIONS

The prematurity rate before 34GW, in twin pregnancies with a previous late pregnancy loss or preterm birth, is not different with or without preventive cervical cerclage.

Plasma progesterone, estradiol, and unconjugated estriol concentrations in twin pregnancies: Relation with cervical length and preterm delivery

INTRODUCTION

The aim of this study was to examine the association between plasma hormone concentrations, cervical length, and preterm delivery in twin pregnancies, including the effect of progesterone treatment.

MATERIAL AND METHODS

This study included 191 women pregnant with twins from a randomized placebo-controlled trial. A baseline blood sample was collected at 18-24 weeks before treatment with vaginal progesterone (n = 95) or placebo pessaries (n = 96), and 167 (87.4%) women had a second sample collected after 4-8 weeks of treatment. At baseline, 155 (81.2%) women had their cervical length measured. Progesterone, estradiol, and unconjugated estriol concentration was measured, and the association between hormone concentrations, cervical length, and gestational age at delivery was examined. Hormone concentrations were compared in the placebo and progesterone group. Statistical analysis included Spearman's rho, Mann-Whitney U test, Cuzick's test for trends, and linear regression analyses.

RESULTS

A short cervical length was associated with preterm delivery. Cervical length and hormone concentrations were not associated (Spearman's rho; progesterone -.05, estradiol .04, estriol .08). Decreasing gestational age at delivery was associated with higher progesterone and estradiol concentrations at baseline (P trend; progesterone 0.04, estradiol 0.02) but not in the second sample or in the weekly change between samples. Progesterone treatment did not increase the progesterone concentration.

CONCLUSIONS

Plasma concentrations of progesterone, estradiol, and unconjugated estriol at 18-24 weeks are not associated with cervical length or preterm delivery in twin pregnancies. Vaginal progesterone treatment does not increase the circulating progesterone concentration in twin pregnancies. Cervical length, but not hormone concentration, is predictive of preterm delivery in twin gestations.

Prevention of Prematurity: Advances and Opportunities

Preterm birth (PTB) rate varies widely and has significant racial and ethnic disparities. Although causal mechanisms are ill understood, socioenvironment, phenotype, and genotype provide insight into pathways for preventing PTB. Data suggest varied response to current medical interventions is explicable Approved by underlying pharmacogenomics. Currently, prevention focuses on minimizing iatrogenic PTB and risk reduction especially in those with prior PTB using proven medical and public health strategies. In the future, preventive approaches will be based on better understanding of sociodemography, nutrition, lifestyles, and underlying individual genetic and epigenetic variation. Statistical approaches and "big-data" models are critical in future study.

Correlation between neonatal outcomes of twins depends on the outcome: secondary analysis of twelve randomised controlled trials

OBJECTIVE

To estimate the magnitude of the correlation between neonatal outcomes of twins and demonstrate how this information can be used in the design of randomised controlled trials (RCTs) in women with twin pregnancies.

DESIGN

Secondary analysis of data from 12 RCTs.

SETTING

Obstetric care in multiple countries, 2004-2012.

POPULATION OR SAMPLE

4504 twin pairs born to women who participated in RCTs to assess treatments given during pregnancy.

METHODS

Intraclass correlation coefficients (ICCs) were estimated using log-binomial and linear models.

MAIN OUTCOME MEASURES

Perinatal death, respiratory distress syndrome, bronchopulmonary dysplasia, intraventricular haemorrhage, necrotising enterocolitis, sepsis, neonatal intensive care unit admission, birthweight, low birthweight and two composite measures of adverse neonatal outcome.

RESULTS

ICCs for the composite measures of adverse neonatal outcome were all above 0.5, indicating moderate to strong correlation between adverse outcomes of twins. For individual neonatal outcomes, median ICCs across trials ranged from 0.13 to 0.79 depending on the outcome. An example illustrates how ICCs can be used in sample size calculations for RCTs in women with twin pregnancies.

CONCLUSIONS

The correlation between neonatal outcomes of twins varies considerably between outcomes and may be lower than expected. Our ICC estimates can be used for designing and analysing RCTs that recruit women with twin pregnancies and for performing meta-analyses that include such RCTs. Researchers are encouraged to report ICCs for neonatal outcomes in twins in their own RCTs.

TWEETABLE ABSTRACT

Correlation between neonatal outcomes of twins depends on the outcome and may be lower than expected.

Controversies about the Secondary Prevention of Spontaneous Preterm Birth

Preterm birth is one of the major global health problems and part of the Millennium Development goals because of the associated high number of perinatal or neonatal mortality and long-term risks of neurodevelopmental and metabolic diseases. Transvaginal sonography has meanwhile been established as a screening tool for spontaneous preterm birth despite its relatively low sensitivity when considering only the cervical length. Vaginal progesterone has been shown to reduce prematurity rates below 34 weeks in a screening population of singleton pregnancies. Up to now, no positive long-term effect could be demonstrated after 2 years. It seems to have no benefit to prolong pregnancies after a period of preterm contractions and in risk patients without cervical shortening. Meta-analyses still demonstrate conflicting results dependent on quality criteria used for selection. A cerclage is only indicated in singleton pregnancies with previous spontaneous preterm birth and a combined cervical shortening in the current pregnancy. Nevertheless, the short- and long-term outcome has never been evaluated, whereas maternal complications may be increased. There is no evidence for a prophylactic cervical cerclage in twin pregnancies even in cases with cervical shortening. Emergency cerclage remains an indication after individual counseling. The effect of a cervical pessary in singleton pregnancy seems to be more pronounced in studies where a few investigators with increasing experience have treated and followed the patients at risk for preterm birth. Mainly in twin pregnancies, pessary treatment seems to be promising compared to other treatment options of secondary prevention when the therapy is started at early stages of precocious cervical ripening. At present, several international trials with the goal to reduce global rates of prematurity are in progress which will hopefully allow to specify the indications and methods of intervention for certain subgroups. When trials are summarized, prospective meta-analyses carry a lower risk of bias than the meanwhile uncontrolled magnitude of retrospective meta-analyses with conflicting results.

Vaginal progesterone for prevention of preterm delivery in women with twin pregnancy: a randomized controlled trial

BACKGROUND

The aim of this study is to evaluate the efficacy of vaginal progesterone to prevent preterm delivery in twin pregnancies and its effect on perinatal outcome.

MATERIALS AND METHODS

A randomized, open label, controlled trial (NCT02350231) was carried out over 70 women, in three different hospitals in Egypt, between February 2015 and January 2017. All eligible pregnant women with twin pregnancies were randomly allocated in a 1:1 ratio into two groups. Group I (Progesterone group) was dispensed, 400 mg of progesterone through a vaginal pessary, each day at bedtime, from the 28th week of pregnancy until delivery. Group II (Control group) received no treatment other than the normal tonics taken during pregnancy. The two study groups were followed until delivery. The primary outcome was the rate of preterm delivery <37 weeks.

RESULTS

No significant differences were observed among both groups of women in terms of delivery <37 weeks (16.9% versus 25.4%; p=0.06) and mode of delivery (vaginal versus cesarean; p=0.31). The mean gestational age at delivery was comparable between both groups (p=0.09). Additionally, no difference, regarding the neonatal outcome, was observed between both groups.

CONCLUSION

Dispensing vaginal progesterone [400 mg] after 28 weeks of gestation does not prevent preterm delivery in twin gestations.

Pessary for prevention of preterm birth in twin pregnancy with short cervix: 3-year follow-up study

OBJECTIVE

A recent randomized clinical trial (ProTWIN) showed that a cervical pessary prevented preterm birth and improved neonatal outcome in women with multiple pregnancy and cervical length (CL) < 38 mm. In this follow-up study, the long-term developmental outcome of these children was evaluated at 3 years' corrected age.

METHODS

This was a follow-up study of ProTWIN, a multicenter trial conducted between 2009 and 2012 in which asymptomatic women with a multiple pregnancy were randomized to placement of a cervical pessary or no intervention. Current follow-up and analysis were limited to mothers with a mid-trimester CL < 38 mm (78 women (157 children) in the pessary group and 55 women (111 children) in the control group). At 3 years of corrected age, surviving children were invited for a Bayley Scales of Infant and Toddler Development-third edition (Bayley-III) assessment. Death after randomization or neurodevelopmental disability (Bayley-III score of ≤ 85, 1 SD below mean) rates were compared between the pessary and control groups, according to the intention-to-treat principle and using multiple imputation for missing data. Mean Bayley-III scores in surviving children were also assessed. A linear mixed-effects model was used to adjust for correlation between children of one mother.

RESULTS

From the time of entry in the ProTWIN trial until follow-up at 3 years of age, a total of 27 children had died (six (5%) in the pessary vs 21 (26%) in the control group; odds ratio (OR), 0.13; 95% CI, 0.04-0.48). Bayley-III outcomes were collected for 173/241 (72%) surviving children (114 (75%) in the pessary vs 59 (66%) in the control group). The cumulative incidence of death or survival with a neurodevelopmental disability was 12 (10%) in the pessary vs 23 (29%) in the control group (OR, 0.26; 95% CI, 0.09-0.73). No statistical or clinically relevant differences were found with respect to cognitive, language and motor development among surviving children between the groups. Comparable results were found after multiple imputation.

CONCLUSION

In women with twin pregnancy and a CL < 38 mm, the use of a cervical pessary strongly improved survival of the children without affecting neurodevelopment at 3 years' corrected age. Copyright © 2018 ISUOG. Published by John Wiley & Sons Ltd.

Ultrasound screening for complications in twin pregnancy

In the decades since the introduction of ultrasound into routine obstetric practice, the advantages of ultrasound have moved beyond the simple ability to identify multiple pregnancies antenatally to the possibility of screening them for fetal anomalies, pre-eclampsia, preterm birth, and the complications specific to monochorionic pregnancies. Screening studies have often excluded twins because physiological differences impact on the validity and sensitivity of the screening tests in routine use in singletons, and therefore, the evidence of screening performance in multiple pregnancy lags behind the evidence from singleton pregnancies. In general, most pregnancy complications are more common in twin pregnancy, but screening tests are less accurate or well validated. In this review article we present the current state of the evidence and avenues for future research relating to the use of ultrasound and screening for complications in twin pregnancies, including the monochorionicity-related pathologies, such as twin-twin transfusion syndrome, selective growth restriction, twin anaemia-polycythaemia sequence and twin reversed arterial perfusion sequence.

Spontaneous preterm birth prevention in multiple pregnancy

KEY CONTENT

Twin pregnancies are associated with a three-fold greater perinatal mortality than singleton pregnancies. Prematurity is a main contributor, with 50% of twin pregnancies delivering before 37 weeks and 10% delivering before 32 weeks of gestation.The aetiology of preterm delivery in twin pregnancies is likely multifactorial and different from that of singletons.Cervical cerclage reduces preterm birth rates in singletons but has mixed results in twins with some studies showing harm.The use of progesterone to prevent preterm birth in singletons has conflicting results and has not been proven to prevent preterm birth in twins. Studies continue to determine whether the cervical pessary is effective in preventing preterm birth in multiple pregnancies.There is a paucity of data available on the prevention of preterm birth in triplets/higher order multiples but similar principles to twin pregnancy apply.

LEARNING OBJECTIVES

To review the burden of preterm birth in multiple pregnancy.To understand the methods available for preventing preterm birth in multiple pregnancies and the evidence surrounding the use of each one.To be aware of the use of the Arabin pessary.

Evaluating progestogens for prevention of preterm birth international collaborative (EPPPIC) individual participant data (IPD) meta-analysis: protocol

BACKGROUND

Preterm birth is the most common cause of death and harm to newborn babies. Babies that are born early may have difficulties at birth and experience health problems during early childhood. Despite extensive study, there is still uncertainty about the effectiveness of progestogen (medications that are similar to the natural hormone progesterone) in preventing or delaying preterm birth, and in improving birth outcomes. The Evaluating Progestogen for Prevention of Preterm birth International Collaborative (EPPPIC) project aims to reduce uncertainty about the specific conditions in which progestogen may (or may not) be effective in preventing or delaying preterm birth and improving birth outcomes.

METHODS

The design of the study involves international collaborative individual participant data meta-analysis comprising systematic review, re-analysis, and synthesis of trial datasets. Inclusion criteria are as follows: randomized controlled trials comparing progestogen versus placebo or non-intervention, or comparing different types of progestogen, in asymptomatic women at risk of preterm birth. Main outcomes are as follows; fetal/infant death, preterm birth or fetal death (<=37 weeks, <=34 weeks, <= 28 weeks), serious neonatal complications or fetal/infant death, neurosensory disability (measured at 18 months or later) or infant/child death, important maternal morbidity, or maternal death. In statistical methods, IPD will be synthesized across trials using meta-analysis. Both 'two-stage' models (where effect estimates are calculated for each trial and subsequently pooled in a meta-analysis) and 'one-stage' models (where all IPD from all trials are analyzed in one step, while accounting for the clustering of participants within trials) will be used. If sufficient suitable data are available, a network meta-analysis will compare all types of progesterone and routes of administration extending the one-stage models to include multiple treatment arms.

DISCUSSION

EPPPIC is an international collaborative project being conducted by the forming EPPPIC group, which includes trial investigators, an international secretariat, and the research project team. Results, which are intended to contribute to improvements in maternal and child health, are expected to be publicly available in mid 2018.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42017068299.