Timing Is Everything: Lengthening the Interpregnancy Interval

Pregnancies conceived within 18 months of a previous birth are more likely to result in preterm birth, low-birth-weight babies, and other adverse health outcomes. To assess the extent to which postpartum contraception promotes longer interpregnancy intervals, researchers linked California's 2008 Birth Statistical Master File to Medicaid data on contraceptive service provision in a cohort of 117,644 women (age range, 15–44) who were seen at publicly funded healthcare facilities within 18 months postpartum.

Only 41% of mothers received contraceptive services within 90 days of delivery; as a result, 36% were pregnant again within 18 months of delivery. Of these, 10% conceived within 6 months and 14% within 7 to 12 months. For every 6 mothers wh…