Interventions to Try to Prevent Preterm Birth in Women With a History of Conization: A Systematic Review and Meta-analyses

The most effective preterm birth (PTB) intervention is unknown for women who are at risk of PTB due to a history of conization. The objective of this systematic review was to determine whether PTB interventions, progesterone, cerclage, and pessary decrease the risk of PTB compared to no treatment in singleton—and separately in twin—pregnancies of women with history of conization. We searched Cochrane Central, MEDLINE, EMBASE, CINAHL, and ClinicalTrials.gov from January 1994 until May 2017. In duplicate, we reviewed titles, abstracts, full texts, extracted data, and assessed quality. We included RCTs and observational studies. Our primary outcomes were PTB