Objectives To evaluate the number of late preterm (LPT) births (between 34 0/7 and 36 6/7 weeks) that could have been prevented if expectant management of preterm premature rupture of membranes (PPROM) had been applied according to new recommendations. Methods A retrospective cohort study included all births at one Swiss center between January 1, 2002 and December 31, 2012. Births were categorized using an adapted evidence-based classification. Two scenarios were considered: best scenario (maximum averted cases) and a conservative scenario (minimum averted cases). Results Among 2017 LPT births (5.0% of all deliveries; n=40,609), 1122 (60.6%) women had PPROM. Spontaneous labor occurred in 473 (42.2%) cases and 649 (57.8%) had induction of labor or an elective cesarean section. In the latter group, 44 (6.8%) had evidence-based indications for LPT delivery and 605 (83.2%) had non-evidence-based indications. Depending on the scenario, the rate of avoided LPT cases would have varied between 4.2% (95% confidence interval [CI]: 3.4-5.2) if the conservative scenario was applied, and 30% (95% CI: 28.0-32.0) for the best scenario. Conclusion Adoption of new guidelines for the management of PPROM will prevent a considerable number of LPT births and help decrease the adverse effects and potential disability associated with late preterm infants.