Vaginal progesterone, oral progesterone, 17‐OHPC, cerclage, and pessary for preventing preterm birth in at‐risk singleton pregnancies: an updated systematic review and network meta‐analysis

Background Recent progesterone trials call for an update of previous syntheses of interventions to prevent preterm birth. Objectives To compare the relative effects of different types and routes of administration of progesterone, cerclage, and pessary at preventing preterm birth in at‐risk women overall and in specific populations. Search strategy We searched Medline, EMBASE, CINAHL, Cochrane CENTRAL, and Web of Science up to 1 January 2018. Selection criteria We included randomised trials of progesterone, cerclage or pessary for preventing preterm birth in at‐risk singleton pregnancies. Data collection and analysis We used a piloted data extraction form and performed Bayesian random‐effects network meta‐analyses with 95% credibility intervals (CrI), as well as pairwise meta‐analyses, rating the quality of the evidence using GRADE. Main results We included 40 trials (11 311 women). In at‐risk women overall, vaginal progesterone reduced preterm birth <34 (OR 0.43, 95% CrI 0.20–0.81) and <37 weeks (OR 0.51, 95% CrI 0.34–0.74), and neonatal death (OR 0.41, 95% CrI 0.20–0.83). In women with a previous preterm birth, vaginal progesterone reduced preterm birth <34 (OR 0.29, 95% CI 0.12–0.68) and <37 weeks (OR 0.43, 95% CrI 0.23–0.74), and 17α‐hydroxyprogesterone caproate reduced preterm birth <37 weeks (OR 0.53, 95% CrI 0.27–0.95) and neonatal death (OR 0.39, 95% CI 0.16–0.95). In women with a short cervix (≤25 mm), vaginal progesterone reduced preterm birth <34 weeks (OR 0.45, 95% CI 0.24–0.84). Conclusions Vaginal progesterone was the only intervention with consistent effectiveness for preventing preterm birth in singleton at‐risk pregnancies overall and in those with a previous preterm birth. Tweetable abstract In updated NMA, vaginal progesterone consistently reduced PTB in overall at‐risk pregnancies and in women with previous PTB.