SPTB and preterm premature rupture of the membranes: As previously noted, a history of sPTB is widely recognized as a risk factor [5] and a small study reported a much higher rate of cervical insufficiency in the subsequent pregnancy of 102 women with PPROM than in 316 without PPROM: 14.7% vs. 1.0%; adjusted OR 3.8, 95% CI 1.2–11.6 [26].