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Objective: The ProTWIN Trial (NTR1858) showed that, in women with a multiple pregnancy and a cervical length < 25(th) percentile (38 mm), prophylactic use of a cervical pessary reduced the risk of adverse perinatal outcome. We investigated whether other maternal or pregnancy characteristics collected at baseline can improve identification of women most likely to benefit from pessary placement., Methods: ProTWIN is a multicenter randomized trial in which 808 women with a multiple pregnancy were assigned to pessary or control. Using these data we developed a multivariable logistic model comprising treatment, cervical length, chorionicity, pregnancy history and number of fetuses, and the interaction of these variables with treatment as predictors of adverse perinatal outcome., Results: Short cervix, monochorionicity and nulliparity were predictive factors for a benefit from pessary insertion. History of previous preterm birth and triplet pregnancy were predictive factors of possible harm from pessary. The model identified 35% of women as benefiting (95% CI, 32-39%), which is 10% more than using cervical length only (25%) for pessary decisions. The model had acceptable calibration. We estimated that using the model to guide the choice of pessary placement would reduce the risk of adverse perinatal outcome significantly from 13.5% when no pessary is inserted to 8.1% (absolute risk reduction, 5.4% (95% CI, 2.1-8.6%))., Conclusions: We developed and internally validated a multivariable treatment selection model, with cervical length, chorionicity, pregnancy history and number of fetuses. If externally validated, it could be used to identify women with a twin pregnancy who would benefit from a pessary, and lead to a reduction in adverse perinatal outcomes in these women. Copyright © 2016 ISUOG. Published by John Wiley & Sons Ltd., (Copyright © 2016 ISUOG. Published by John Wiley & Sons Ltd.)

Introduction: We recently showed that a cervical pessary prevents preterm birth and reduces poor neonatal outcomes in women with a twin pregnancy and a short cervix (<38 mm). The objective of this study was to evaluate the full potential treatment effect of the pessary in the whole group and in women with a short cervix., Material and Methods: We performed a per-protocol analysis of a multicenter randomized controlled trial (ProTWIN trial, NTR1858) where we excluded women who were allocated to the pessary but never had it placed. Women who had the pessary removed before 36 gestational weeks and did not deliver within 7 days after removal, were excluded. Analyses were performed on all women and in those with a cervical length <38 mm., Results: In 23 (6%) women the pessary was not placed. In women with a cervical length <38 mm (25th percentile) the pessary reduced poor perinatal outcome (relative risk 0.32, 95% confidence interval 0.13-0.78) and birth at <32 weeks (relative risk 0.41, 95% confidence interval 0.20-0.87). After excluding 47 (12%) women, the time to delivery was longer in the pessary group than in the control group (whole group: hazard ratio 0.68, 95% confidence interval 0.55-0.82, cervical length <38 mm: hazard ratio 0.35, 95% confidence interval 0.22-0.57)., Conclusions: The analysis confirms the principal findings of the intention-to-treat analysis. Time to delivery was longer in the pessary group than in the control group when censored data were used. This implies the pessary should not be removed until labor is evident., (© 2016 Nordic Federation of Societies of Obstetrics and Gynecology.)

Objective: To determine whether second-trimester cervical length (CL) in women with a twin pregnancy is associated with the risk of emergency Cesarean section., Methods: This was a secondary analysis of two randomized trials conducted in 57 hospitals in The Netherlands. We assessed the univariable association between risk indicators, including second-trimester CL in quartiles, and emergency Cesarean delivery using a logistic regression model. For multivariable analysis, we assessed whether adjustment for other risk indicators altered the associations found in univariable (unadjusted) analysis. Separate analyses were performed for suspected fetal distress and failure to progress in labor as indications for Cesarean section., Results: In total, 311 women with a twin pregnancy attempted vaginal delivery after 34 weeks' gestation. Emergency Cesarean delivery was performed in 111 (36%) women, of which 67 (60%) were performed owing to arrest of labor. There was no relationship between second-trimester CL and Cesarean delivery (adjusted odds ratio (aOR): 0.97 for CL 26(th) -50(th) percentiles; 0.71 for CL 51(st)  - 75(th) percentiles; and 0.92 for CL > 75(th) percentile, using CL ≤ 25(th) percentile as reference). In multivariable analysis, the only variables associated with emergency Cesarean delivery were maternal age (aOR, 1.07 (95% CI, 1.00-1.13)), body mass index (BMI) (aOR, 3.99 (95% CI, 1.07-14.9) for BMI 20-23 kg/m(2) ; 5.04 (95% CI, 1.34-19.03) for BMI 24-28 kg/m(2) ; and 3.1 (95% CI, 0.65-14.78) for BMI > 28 kg/m(2) ) and induction of labor (aOR, 1.92 (95% CI, 1.05-3.5))., Conclusion: In nulliparous women with a twin pregnancy, second-trimester CL is not associated with risk of emergency Cesarean delivery., (Copyright © 2014 ISUOG. Published by John Wiley & Sons Ltd.)

Objective: Cervical length (CL) is associated with the risk of preterm birth (PTB) in multiple pregnancies. However, the position of CL within the pathophysiological pathway of PTB is unclear, and it is unknown which factors are predictive for CL. This study aims to investigate whether in twin pregnancies baseline maternal and obstetrical characteristics are potential indicators for CL, to improve insight in the pathophysiological pathway of PTB., Study Design: Secondary analysis of data on twin pregnancies and CL measurement between 16 and 22 weeks. A set of 10 potential indicators, known to be associated with an increased risk of PTB and/or which have a plausible mechanism resulting in a change of CL were selected. We used multivariable linear regression with backward selection to identify independent indicators for CL., Results: A total of 1,447 women with twin pregnancies were included. Mean CL was 43.7 (±8.9) mm. In multivariable analysis, age (0.27 mm/y; 95% confidence interval [CI] 0.16 to 0.39), use of assisted reproductive technologies (ART) (-1.42 mm, 95% CI -2.6 to -0.25), and having delivered at term in a previous pregnancy (1.32 mm, 95% CI 0.25 to 2.39) were significantly associated with CL., Conclusion: This study shows that in twin pregnancies, age, use of ART and having delivered term in a previous pregnancy has an association with CL., (Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.)

Objective: To assess the cost-effectiveness of a cervical pessary to prevent preterm delivery in women with a multiple pregnancy., Methods: The study design comprised an economic analysis of data from a randomized clinical trial evaluating cervical pessaries (ProTWIN). Women with a multiple pregnancy were included and an economic evaluation was performed from a societal perspective. Costs were estimated between the time of randomization and 6 weeks postpartum. The prespecified subgroup of women with a cervical length (CL) < 25(th) centile (< 38 mm) was analyzed separately. The primary endpoint was poor perinatal outcome occurring up to 6 weeks postpartum. Direct medical costs and health outcomes were estimated and incremental cost-effectiveness ratios for costs to prevent one poor outcome were calculated., Results: Mean costs in the pessary group (n = 401) were € 21,783 vs € 21,877 in the group in which no pessary was used (n = 407) (difference, -€ 94; 95% CI, -€ 5975 to € 5609). In the prespecified subgroup of women with a CL < 38 mm we demonstrated a significant reduction in poor perinatal outcome (12% vs 29%; RR, 0.40; 95% CI, 0.19-0.83). Mean costs in the pessary group (n = 78) were € 25,141 vs € 30,577 in the no-pessary group (n = 55) (difference, -€ 5436 (95% CI, -€ 11,001 to € 1456). In women with a CL < 38 mm, pessary treatment was the dominant strategy (more effective and less costly) with a probability of 94%., Conclusion: Cervical pessaries in women with a multiple pregnancy involve costs comparable to those in women without pessary treatment. However, in women with a CL < 38 mm, treatment with a cervical pessary appears to be highly cost-effective., (Copyright © 2014 ISUOG. Published by John Wiley & Sons Ltd.)

Objectives: The aim of this study is to present a systematic review of available literature on the effect of maternal ethnicity (Africans/blacks, Asians, Hispanics, others) on the risk of preterm birth (PTB)., Study Design: Studies investigating ethnicity (or race) as a risk factor for PTB were included if performing adjustments for confounders. A meta-analysis was performed, and data were synthesized using a random effects model., Results: Forty-five studies met the inclusion criteria. Black ethnicity was associated with an increased risk of PTB when compared with whites (range of adjusted odds ratios [ORs] 0.6 to 2.8, pooled OR 2.0; 95% confidence interval [CI] 1.8 to 2.2). For Asian ethnicity, there was no significant association (range of adjusted ORs 0.6 to 2.3). For Hispanic ethnicity, there also was no significant association (range of adjusted ORs 0.7 to 1.5)., Conclusions: Ethnic disparities in the risk of PTB were clearly pronounced among black women. Future research should focus on preventative strategies for ethnic groups at high risk for PTB. Information on ethnic disparities in risk of PTB-related neonatal morbidity and mortality is lacking and is also a topic of interest for future research., (Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.)

Objective. The aim of this study was to assess whether cervical length measurement (CL) could predict preterm birth (PTB) in symptomatic women with a twin pregnancy. Methods. We searched MEDLINE and EMBASE to identify studies investigating the accuracy of CL measurement in predicting PTB in symptomatic women with a twin pregnancy. We extracted data to construct two-by-two tables and used bivariate meta-analysis to generate point estimates of sensitivity and specificity. Results. Five studies (N = 226) were included. Variation in definition of PTB and cut-off points for CL was strong. One study investigated delivery within seven days, demonstrating a sensitivity of 1.0 (95% CI: 0.83-1.0) and a specificity of 0.31 (95% CI 0.2-0.43) for a CL cutoff at 25 mm. Three studies reported on predicting PTB < 37 weeks at a CL cutoff of 30 mm, with sROC point estimates of 0.76 (95% CI: 0.66 to 0.84) and 0.37 (95% CI: 0.21 to 0.56) for sensitivity and specificity, respectively. For preterm birth <34 weeks, no pooled estimates could be estimated since only 2 studies with large heterogeneity were identified. Conclusions. There is limited evidence on the accuracy of cervical length measurement testing the prediction of preterm birth in symptomatic women with a twin pregnancy, especially on the most important outcome, that is, delivery within 7 days.

Introduction. Reduction of preterm birth is a major goal in obstetric care. We performed a systematic review of randomized controlled trials and cohort studies on the effectiveness of the cervical pessary to prevent preterm birth. Methods. We searched the electronic databases of MEDLINE and Embase from inception until April 2012 to identify studies investigating treatment with a cervical pessary to prevent preterm birth. We constructed two-by-two tables for delivery before 28, 34, and 37 weeks of gestation and calculated relative risks (RRs) with 95% confidence intervals. Results. The search revealed 103 potentially eligible abstracts of which six cohort studies and four randomized controlled trials (RCTs) investigated the effectiveness of the pessary. One RCT (n = 380) demonstrated a lower delivery rate prior to 34 weeks (RR 0.24; 95% CI 0.13-0.43) in the pessary group, while another RCT (n = 108) showed no positive effect of pessary for delivery before 34 weeks (RR 1.73; 95% CI 0.43-6.88). Two older quasi randomized studies and cohort studies indicated potential effect of the pessary. Conclusions. Available randomized and nonrandomized studies indicate potential effectiveness of a cervical pessary in the prevention of preterm birth. More randomized clinical trials are needed before this device can be used in clinical practice.