Vaginal delivery after caesarean section triples risk of uterine ruptureBMJ 2001; 323 doi: https://doi.org/10.1136/bmj.323.7304.68 (Published 14 July 2001) Cite this as: BMJ 2001;323:68
Women who have a vaginal delivery after a caesarean section face three times the risk of uterine rupture than those who have a second caesarean section, a new report has said (New England Journal of Medicine 2001;345:3-8).
The study bolsters the old adage, “Once a caesarean section, always a caesarean section.” Moreover, the risk of rupture was five times greater in women whose labour was induced by prostaglandins than in those whose labour was spontaneous.
Researchers at the University of Washington in Seattle reached these conclusions from a retrospective cohort analysis of 20 095 women who delivered their first baby via caesarean section and then had a second child.
Ninety one cases of uterine rupture overall were recorded. Uterine rupture occurred in 1.6 per 1000 deliveries among women with a repeat caesarean delivery without labour (11 women) and in 24.5 per 1000 deliveries among women with prostaglandin induced labour (9 women).
Among women with a vaginal delivery, those whose labour was induced with a prostaglandin had the highest risk of rupture. The rate of rupture was 5.2 per 1000 for those women in whom the onset of labour was spontaneous and 7.7 per 1000 for those whose labour was induced without prostaglandins.
Uterine ruptures place both the mother and fetus at risk. Fetal loss can occur through acute blood loss, and mothers face life threatening haemorrhage as well as possible hysterectomies.
The incidence of infant death was 10 times as high among the 91 women who had uterine rupture as among the 20 004 who did not (5.5% v 0.5%).
Between 1989 and 1996 there was a movement in the United States against repeat caesarean sections, and the rate of vaginal births after caesarean sections increased by 50%. A backlash then took place, and by 1999 the rate had fallen.