Vaginal progesterone is most beneficial for the prevention of preterm birth in women at high risk

Reference

Care A, Nevitt SJ, Medley N, et al. Interventions to prevent spontaneous preterm birth in women with singleton pregnancy who are at high risk: systematic review and network meta-analysis. BMJ 2022;376;064547.

Synopsis

This paper details the meta-analysis conducted for the Cochrane Library to assess the comparative effectiveness of preventive treatments for spontaneous preterm birth among women with singleton pregnancy and history of preterm birth, cervical incompetence, or shortened cervix identified on ultrasound. The authors conducted a literature search through August 2021. They identified 61 randomized controlled trials (17,273 women) that met inclusion criteria. They chose main outcomes of preterm birth at less than 34 weeks (40 trials with 13,310 women) and perinatal death (30 trials with 12,119 women). The treatments included were bed rest, cervical cerclage, cervical pessary, fish oils and omega fatty acids, nutritional supplements (zinc), progesterone (by oral, vaginal, or intramuscular route), prophylactic antibiotics, prophylactic tocolytics, combinations of interventions, and placebo or no treatment as controls. The authors conducted meta-analyses by comparing each treatment individually with control, and pairs of treatments with each other. Vaginal progesterone was the only treatment with comparison to control that was associated with a decreased risk of preterm birth at less than 34 weeks (odds ratio [OR] 0.50; 95% CI 0.34 - 0.70 [high certainty of evidence]), or with decreased risk of perinatal death (OR 0.66; 0.44 - 0.97 [moderate certainty of evidence]), for which the confidence intervals didn’t cross 1.0. In addition, comparisons between vaginal progesterone and other routes of administration or other treatments failed to identify any other treatment as superior. Multiple secondary outcomes for women and neonates were considered and were generally consistent with the main results. Only progesterone treatments were associated with reductions in neonatal respiratory distress syndrome, neonatal sepsis, necrotizing enterocolitis, and admission to neonatal intensive care units compared with controls.