First cesarean birth and subsequent fertility.

Objective: To determine whether cesarean delivery is independently associated with later subfertility.

Design: Retrospective cohort study.

Setting: Maternity records kept for Scotland, 1980-1999.

Patient(s): The study included 109,991 women who had first births between 1980 and 1984, excluding multiple or preterm births and perinatal deaths.

Intervention(s): Exposures studied were spontaneous vaginal birth, operative vaginal birth, planned cesarean delivery for breach presentation, planned cesarean delivery for other indications, and emergency cesarean delivery.

Main Outcome Measure(s): The relative risk of not having a second pregnancy over the following 15 years, the interpregnancy interval, and the number of spontaneous early pregnancy losses between the first and second birth.

Result(s): Women who delivered by planned cesarean section for breech presentation had an increased risk of not having a second birth compared with women whose first birth was a spontaneous vertex delivery (relative risk [RR]: 1.21, 95% confidence interval [CI]: 1.14 to 1.29). However, after adjustment for maternal and obstetric characteristics, there was no longer a strong association (adjusted RR: 1.07, 95% CI: 1.00 to 1.15). Operative vaginal delivery (forceps and vacuum extraction) and all types of cesarean delivery were associated with longer interpregnancy intervals. There was no relationship between mode of delivery and the number of spontaneous early pregnancy losses between the first and second birth.

Conclusion(s): It is unlikely that delivering by cesarean section in a first pregnancy decreases a woman's likelihood of having a second viable pregnancy.