Worth the Wait: The Effect of Early-Term Birth on Maternal and Infant Health

While infants born at 37 or 38 weeks gestation are not considered premature, these “early term” births still have an increased risk of serious adverse health outcomes compared to infants born at 39 weeks or later.  In this paper, we document a rise in early-term births in the United States from 1989 to the mid-2000’s, followed by a decline in recent years.  We first show that this pattern cannot be attributed to changes in the demographic composition of mothers. We posit that the decline in early-term births has been driven by changes in medical practice advocated by American College of Obstetricians and Gynecologists recommendations and programs such as the March of Dimes’ “Worth the Wait” campaign. Exploiting county-level variation in the timing of the changes in medical practice, we show that early-term inductions lead to lower birth weights and an increased risk of birth injury.