Natural Birth After a C-Section Shown to Be Slightly Riskier Than Repeat Surgery, but Complication Rate Low for Both
By Salynn Boyles
WebMD Health News
Reviewed by Louise Chang, MD
March 13, 2012 -- Planned repeat cesarean section is linked to healthier outcomes among mothers and babies compared to vaginal birth after cesarean, or VBAC, in a new study from Australia.
Death and serious health issues associated with either delivery method were rare.
But women in the study who had planned surgical deliveries experienced fewer serious bleeding issues compared to women who planned to have VBAC deliveries, and their babies were about half as likely to die or suffer serious health problems around the time of birth.
VBAC Rates Declining
One in three babies born in the United States is delivered by cesarean section, and the rate of vaginal deliveries in women who have had C-sections continues to decline.
Many ob-gyns no longer offer VBAC deliveries to their patients, and many insurers no longer pay for them.
While the Australian study suggests that planned repeat cesarean sections may be safer than labor in women who have had previous C-sections, it isn't that simple, says Catherine Y. Spong, MD, of the National Institute of Child Health and Human Development.
Repeat C-sections carry their own risks, and those risks rise with each pregnancy.
"The big take-home for me is that we need to prevent the first cesarean delivery whenever possible," she tells WebMD. "Clearly the safest delivery method for both mother and baby is an uncomplicated vaginal delivery. The problem is, we don't know which patients will have uncomplicated deliveries."
2 Stillbirths in Planned VBAC Group
The Australian study included 2,345 pregnant women who had one previous delivery by C-section and were considered candidates for VBAC.
Planned C-section deliveries were scheduled for 1,108 women and VBAC deliveries were planned for the remaining 1,237 women.
But less than half (43%) of the women who chose to labor ended up having vaginal deliveries. The rest had elective C-sections or had emergency surgical deliveries due to complications.
There were two unexplained stillbirths in the planned vaginal delivery group. There were no infant deaths among babies born to women who had scheduled cesarean section.
The rate of fetal or infant death or serious health issues prior to hospital discharge was 2.4% in the planned VBAC group, compared to 0.9% in the planned C-section group.
The researchers concluded that while the actual risk for both forms of delivery was quite small, elective repeat C-sections were associated with significantly lower risk for both mother and baby.
Uterine Rupture Linked to Repeat C-Section
In a related study, researchers in the U.K. found that repeat C-sections raised the risk for uterine rupture, a rare but very serious pregnancy complication.
Risk was highest among women who had two or more prior C-sections and those who had repeat C-sections less than 12 months after the last C-section.
Of the 159 uterine ruptures identified in the study, 139 occurred among women who had previously had a C-section.
Both studies appear in the March issue of the journal PLoS Medicine.
Ob-gyn professor F. Gary Cunningham, MD, says while the risks are small, no method of childbirth is risk-free. Cunningham is a distinguished chair in obstetrics and gynecology at the University of Texas Southwestern Medical Center in Dallas.
In 2010, he chaired a panel of experts convened by the National Institutes of Health to explore the reasons for the decline in VBAC deliveries in the U.S.
In the mid-1990s, about 1 in 4 deliveries following a C-section were vaginal, compared to around 1 in 10 today, Cunningham tells WebMD.
The panel concluded that VBAC was a safe alternative to repeat C-section for women who had had a single C-section delivery.
"No matter what delivery method is used, there are going to be some rare bad outcomes," Cunningham says. "But if a woman knows the risks and is a candidate for a trial of labor, she should be able to have one."
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SOURCES: Crowther, C.A. PLoS Medicine, March 2012. Fitzpatrick, K.E. PLoS Medicine, March 2012. Catherine Y. Spong, MD, branch chief, pregnancy and perinatology, National Institute of Child Health & Human Development. F. Gary Cunningham, MD, professor and chairman, department of obstetrics and gynecology, University of Texas Southwestern Medical Center, Dallas. News release, Public Library of Science.
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