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

Abstract Objective The present study aims to determine if the use of cervical pessary plus progesterone in short-cervix (≤ 25 mm) dichorionic-diamniotic (DC-DA) twin pregnancies is equivalent to the rate of preterm births (PBs) with no intervention in unselected DC-DA twin pregnancies. Methods A historical cohort study was performed between 2010 and 2018, including a total of 57 pregnant women with DC-DA twin pregnancies. The women admitted from 2010 to 2012 (n = 32) received no treatment, and were not selected by cervical length (Non-Treated group, NTG), whereas those admitted from 2013 to 2018 (n = 25), were routinely submitted to cervical pessary plus progesterone after the diagnosis of short cervix from the 18th to the 27th weeks of gestation (Pessary-Progesterone group, PPG). The primary outcome analyzed was the rate of PBs before 34 weeks. Results There were no statistical differences between the NTG and the PPG regarding PB < 34 weeks (18.8%; versus 40.0%; respectively; p = 0.07) and the mean birthweight of the smallest twin (2,037 ± 425 g versus 2,195 ± 665 g; p = 0.327). The Kaplan-Meyer Survival analysis was performed, and there were no differences between the groups before 31.5 weeks. Logistic regression showed that a previous PB (< 37 weeks) presented an odds ratio (OR) of 15.951 (95%; confidence interval [95%;CI]: 1.294-196.557; p = 0.031*) for PB < 34 weeks in the PPG. Conclusion In DC-DA twin pregnancies with a short cervix, (which means a higher risk of PB), the treatment with cervical pessary plus progesterone could be considered equivalent in several aspects related to PB in the NTG, despite the big difference between these groups.

【摘要 目的】本研究旨在明确：短宫颈（short-cervix，≤25mm）双绒毛膜双羊膜囊（dichorionic-diamniotic, DC-DA）双胎妊娠患者，采用宫颈托（cervical pessary）联合孕激素（progesterone）治疗后的早产（preterm birth, PB）发生率，是否与未筛选的DC-DA双胎妊娠未采取任何干预措施时的早产率相当。
【方法】本研究为2010年至2018年间开展的历史性队列研究（historical cohort study），共纳入57名DC-DA双胎妊娠孕妇。2010年至2012年入组的32名孕妇未接受任何治疗，且未按宫颈长度进行筛选，设为未治疗组（Non-Treated group, NTG）；2013年至2018年入组的25名孕妇在妊娠18至27周确诊短宫颈后，常规接受宫颈托联合孕激素治疗，设为宫颈托-孕激素组（Pessary-Progesterone group, PPG）。本研究的主要结局指标为34周前早产发生率。
【结果】未治疗组与宫颈托-孕激素组在34周前早产率（分别为18.8%与40.0%；p=0.07）以及最小双胎儿的平均出生体重（2037±425g vs 2195±665g；p=0.327）方面均无统计学差异。经Kaplan-Meier生存分析（Kaplan-Meyer Survival analysis），两组在妊娠31.5周前无显著差异。Logistic回归分析（logistic regression）显示，宫颈托-孕激素组中，既往存在<37周早产史的孕妇发生<34周早产的优势比（odds ratio, OR）为15.951（95%置信区间[95%CI]:1.294~196.557；p=0.031*）。
【结论】对于合并短宫颈的DC-DA双胎妊娠（此类妊娠早产风险更高），尽管两组基线差异较大，但联合使用宫颈托与孕激素的治疗方案，在与早产相关的多项指标上，可视为与未治疗组效果相当。