Spontaneous preterm labor and premature rupture of membranes at late preterm gestations: to deliver or not to deliver.

Nationwide the American College of Obstetricians and Gynecologists noted in 1995 that the survival rate for newborns at 34 weeks is within 1% of those born at or beyond 37 weeks. Newborn major morbidity is slightly but significantly increased from 34(0) to 36(6) compared with 37 or greater weeks. These data form the basis for and reflect the perinatal outcomes associated with the standardized obstetric practices of effecting delivery for women with amnion rupture and also of not attempting tocolysis for preterm labor at or beyond 34(0) weeks gestation. Pragmatically, a prospective randomized management trial of women at late preterm gestation (34(0) to 36(6)) and with spontaneous preterm labor or amnion rupture would require multi-institutional support to achieve a required study population.