Temporal and gestational age trends: what is the effect of obstetric intervention?

摘要

The recently described shift in peak distribution of U.S. gestational age at delivery from 40 to 39 weeks of gestation may reflect an underlying physiologic change in the U.S. population and is not exclusively related to obstetric intervention. During the work week, factors other than medical necessity appear to have a marked association with both timing of delivery and rate of cesarean delivery and may affect up to one third of primary cesarean deliveries.