Journal Article

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

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

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

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

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

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