Interventions for preventing preterm birth in multiple gestations with short cervix -- a systematic review and network meta-analysis

Abstract

Background: Multiple gestation has a higher incidence of preterm birth(PTB), especially in the presence of a short cervix. Objectives: To perform a systematic review and network meta-analysis(NMA) evaluating the effect of progesterone, cerclage, cervical pessary and their combination as treatments for preventing PTB<34 weeks. Search strategy: PubMed, MEDLINE, Cochrane Library, EMBASE, Web of Science, BVS, Scopus, and grey literature were explored. Selection criteria: We included randomized controlled trials that compared an intervention with a control group or another intervention to prevent PTB in women with a twin pregnancy and a short cervix<40mm. Data collection and Analysis:Studies were checked for trustworthiness. We presented summary relative effect sizes(Odds Ratios) for each possible pair of interventions and we used the surface under the cumulative ranking curves(SUCRA) to rank all interventions. Main Results: A total of 20 studies participated in NMA. We found no evidence that the combined treatment of pessary and vaginal progesterone reduced the risk of spontaneous PTB <34 weeks when compared to no intervention(OR 0.68; 95%CI 0.16 to 2.9). Also, pessary(OR 0.78; 95%CI 0.49 to 1.3), vaginal progesterone(OR 0.79; CI95% 0.45 to 1.4) and injectable 17-OH progesterone alone(OR 0.85; CI95% 0.26 to 2.8) did not show a statistically significant reduction in spontaneous PTB. For overall PTB<34 weeks, findings were similar. Conclusions: We found no evidence that progesterone, cervical pessary, cerclage or their combination reduce PTB<34 weeks. There is an urgent need for randomized trials assessing these treatments in women with a multiple pregnancy and a short cervix.