A major study led by the University of Adelaide has found that women who have had one prior cesarean can lower the risk of death and serious complications for their next baby -- and themselves -- by electing to have another cesarean.

The study, known as the Birth After Caesarean (BAC) study, is the first of its kind in the world. It involves more than 2300 women and their babies and 14 Australian maternity hospitals. The results are published this week in the international journal, PLoS Medicine.

The study shows that infants born to women who had a planned elective repeat cesarean had a significantly lower risk of serious complications compared with infants born to mothers who had a vaginal birth following a prior cesarean -- the risk of death or serious complication for the baby is 2.4% for a planned vaginal birth, compared with 0.9% for a planned elective repeat cesarean.

The mothers of these babies were also themselves less likely to experience serious complications related to birth. For example, the risk of a major hemorrhage in the mother is 2.3% for a planned vaginal birth, compared with 0.8% for a planned elective repeat cesarean.

"Until now there has been a lack of high-quality evidence comparing the benefits and harms of the two planned modes of birth after previous cesarean," says the study's leader, Professor Caroline Crowther from the Australian Research Centre for the Health of Women and Babies (ARCH), part of the University of Adelaide's Robinson Institute.

"The information from this study will help women, clinicians and policy makers to develop health advice and make decisions about care for women who have had a previous cesarean.

"Both modes of birth have benefits and harms. However, it must be remembered that in Australia the risks for both mother and infant are very small for either mode of birth," Professor Crowther says.

Cesarean section is one of the most common operations performed on childbearing women, with rates continuing to rise worldwide. Repeat cesarean births are now common in many developed nations.

In Australia in 2008, more than 90,700 women gave birth by cesarean, accounting for more than 31% of all births. Of Australian women who had a previous cesarean section, 83.2% had a further cesarean for the birth of their next child. In South Australia alone, repeat cesarean births amount to 28% of the overall cesarean section rate.

"We hope that future research will follow up mothers and children involved in this study, so that we can assess any longer term effects of planned mode of birth after cesarean on later maternal health, and the children's growth and development," Professor Crowther says.

The BAC study is funded by the National Health and Medical Research Council (NHMRC) and the Women's and Children's Hospital Research Foundation.

The study is coordinated by researchers from the University of Adelaide's Discipline of Obstetrics and Gynaecology and Discipline of Public Health; Department of Neonatal Medicine at the Women's and Children's Hospital, Adelaide; and the Faculty of Health Sciences at the Australian Catholic University, Melbourne, with collaboration from clinicians at the 14 participating maternity hospitals.