Caesarean section is associated with an increased risk of placental disorders in future pregnancies, but the effects on stillbirth rates are unknown. Gordon Smith from the University of Cambridge, UK, and colleagues assessed whether previous caesarean delivery is associated with an increased risk of stillbirth.
Using data for 120,000 births in Scotland between 1992 and 1998, the proportion of stillbirths was greater (2.4 per week per 10,000 women) for women who had previously given birth by caesarean section than women who had undergone previous vaginal delivery (1.4 per 10,000 women per week). The increased risk of stillbirth-mainly stillbirth without any known cause-started at around 34 weeks of the second pregnancy for those women who had previously undergone caeserean section for their first child. The risk of stillbirth was the same regardless of the reason for the original caesarean section.
Gordon Smith comments: "Our results are of relevance for women considering
caesarean delivery who are planning further pregnancies. The absolute risk
of perinatal death associated with vaginal breech delivery at term is around
8.3 per 1000 births. Caesarean section reduces the risk of perinatal
morbidity and mortality associated with vaginal breech birth. The overall
excess risk of stillbirth in a second pregnancy that was associated with a
previous caesarean delivery was below one per 1000, which is unlikely to
influence the decision to have a caesarean section for breech presentation
in a first pregnancy. However, if women are being counselled about caesarean
birth with no clear obstetric advantage, such as caesarean section for
Contact: Richard Lane