For women who delivered their first baby by cesarean section, delivering a second baby also by C-section may be somewhat safer for both mother and baby than a vaginal birth, a new study reveals.
Australian researchers found that, among babies born by a planned repeat C-section, 0.9 percent died or had serious complications, compared with 2.4 percent of babies born by a planned vaginal birth after a previous C-section.
And 0.8 percent of mothers who had a repeat C-section experienced severe bleeding, while 2.3 percent of those who gave birth vaginally after a previous C-section did.
"The risks for women and their babies are small," but there were significant differences between the groups, said study author Dr. Caroline Crowther, a professor of obstetrics and gynecology at the Australian Research Centre for Health of Women and Babies in Adelaide.
The study is published March 13 in the journal PLoS Medicine.
Changing views on cesareans
For a long time, it was believed that women who had a cesarean delivery would need C-sections for all future pregnancies. The most feared complication of delivering vaginally after a C-section is a rupture of the uterus during labor, which can result in a hysterectomy for a mother or neurological complications for a baby. But uterine ruptures are uncommon.
In 2010, the National Institutes of Health (NIH) asked a panel of experts to review the scientific evidence on the matter, because some U.S. hospitals had banned vaginal births after the mother had a cesarean, and many doctors were advising against them.
The NIH panel recommended that a "trial of labor," meaning a planned attempt to give birth vaginally, was a "reasonable option" for many pregnant women who had one prior cesarean.
Months later, the American College of Obstetrics and Gynecology updated its guidelines, expanding the NIH recommendations and suggesting vaginal delivery after Cesarean was "a safe and appropriate option for most women" — including women who have had two C-sections and those carrying twins.
In the new study, scientists followed 2,323 pregnant women in Australia who gave birth at 14 hospitals over a five-year period. All had given birth once before via C-section, and were at least 37 weeks along in their pregnancies. None were having twins or other multiples.
About 1,225 women planned to have a vaginal delivery, while nearly 1,100 women elected to have a repeat cesarean. When the time came to give birth, 98 percent of the mothers who planned to have a C-section succeeded at delivering that way, while only 43 percent of women hoping for a vaginal delivery after a first cesarean did.
There were no infant deaths among the babies born by a planned C-section; two babies were stillborn among the planned vaginal deliveries.
According to the National Center for Health Statistics, the rate of cesarean deliveries reached an all-time high in 2009, at roughly one in three U.S. births.
Weighing risks and benefits
Dr. C. Edward Wells, a clinical professor of obstetrics at University of Texas Southwestern Medical Center in Dallas, was part of the NIH panel. He said the new study was "fascinating" because it was one of the first to consider women's planned preferences for birth.
Wells said he was surprised to see a higher risk of infant death and serious complications in the vaginal delivery group. However, he said, it was reassuring that the mothers had a low risk of uterine rupture.
The researchers also conducted, within their study, a small randomized trial, the gold standard in medical research.
The trial had only 22 patients — most women did not want to participate because it meant giving up their choice of delivery method, and being assigned to a group by the scientists. None of the mothers or babies in the trial developed any complications.
Wells noted the trial looked at the very best candidates for vaginal births after having a cesarean.
"I think this study will become an important reference for many of us," Wells said.
Dr. Jeffrey Ecker, a high-risk obstetrician at Massachusetts General Hospital in Boston, agreed this was a large, well-done study.
"The most important message for many women with a single prior C-section is that a trial of labor is a safe and appropriate alternative to a planned repeat C-section delivery in a second pregnancy," Ecker said.
For some women, there may be a small benefit to having a planned repeat C-section, but couples need to view their decisions in terms of their individual circumstances, he said.