Spontaneous late preterm births: what can be done to improve outcomes?

Despite the increase in indicated late preterm births, spontaneous preterm labor and preterm premature rupture of the fetal membranes are the most common antecedent diagnoses leading to births between 34-0/7 and 36-6/7 weeks of gestation. Regional and institutional variation in the rates of late spontaneous preterm birth suggests that there may be opportunities to reduce the number of these births. This article summarizes the factors contributing to late spontaneous preterm birth and offers suggestions to improve care for these mothers and infants.