Prospective cohort study designed to investigate the association between mode of delivery at first childbirth (cesarean or vaginal) and subsequent fecundity and fertility over the course of a 3-year follow-up period. Women were enrolled during pregnancy and interviewed by telephone in their third trimester. Enrolled participants were followed-up with and surveyed at 1, 6, 12, 18, 24, 30 and 36 months postpartum. Participants were enrolled in 2009 to 2011 and the last interview was conducted in 2014.