Late preterm birth: how often is it avoidable?

Objective: Our objective was to describe indications for late preterm birth (LPTB) and estimate the frequency of potentially avoidable LPTB deliveries. Study Design: Singleton pregnancies delivered between 34^0/7-36^6/7 weeks over a 1-year period at a tertiary care medical center were studied. Indications for delivery were categorized as spontaneous (spontaneous preterm birth or premature rupture of membranes) or iatrogenic (elective or medically indicated). Potentially avoidable deliveries were defined as those with elective or medical stable, but high-risk indications. Results: During the study period there were 514 LPTB (spontaneous preterm birth 36.2%, preterm premature rupture of membranes 17.7%, medically indicated 37.9%, and elective 8.2%). Potentially avoidable LPTB accounted for 17% of LPTB and were associated with later gestational age (odds ratio [OR], 4.7; 95% confidence interval [CI], 2.5-8.6), nonfaculty physician status (OR, 2.8; 95% CI, 1.5-5.1), and prior cesarean delivery (OR, 1.5; 95% CI, 1.0-2.1). Conclusion: At our institution, <10% of LPTB are purely elective and >80% are clearly unavoidable.