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.