Pregnant women who have had a previous cesarean section may now be given the option of having a vaginal birth if doctors get on board with guidelines issued yesterday by the American College of Obstetricians and Gynecologists. The organization says that the procedure, known as vaginal birth after cesarean, or VBAC, is safe and appropriate for most women who have had one prior C-section (with a horizontal incision below the bikini line) and even for some who have had two previous incisions or those carrying twins. "The potential risks and benefits" of both VBAC and a repeat C-section should be discussed, and the "ultimate decision...should be made by the patient in consultation with her health care provider," read the guidelines, which were published in the August issue of Obstetrics and Gynecology.
The latest recommendations are similar to those issued in April by a National Institutes of Health expert panel and are driven by concern over a recent spike in C-sections in the U.S., with a rate that's jumped from 5 percent to more than 31 percent in the past 40 years. Although VBACs used to be performed routinely, they declined dramatically after a handful of studies found that women who tried vaginal labor following a C-section had higher rates of uterine rupture, which can be life threatening for both mother and baby. While still a concern, more recent research has demonstrated that the risk of rupture is very small, less than one percent, and the risk of serious complications even smaller. What's more, a VBAC lowers a woman's risk of excessive bleeding and infections and usually means a less painful and shorter recovery than if she had surgery. Long term, women who avoid repeat C-sections have a lower risk of having complications with future pregnancies, like abnormal placenta conditions, bladder or bowel injuries, or requiring a hysterectomy.
But deciding which route to take is hardly simple for pregnant women and their doctors. Having a planned repeat C-section poses more risks than having a successful VBAC, according to the latest research. However, having an emergency repeat C-section after a difficult labor carries the greatest risks. Studies suggest that about 60 to 80 percent of labor attempts following a previous C-section will successfully end in a vaginal birth, which is a high percentage from a public health standpoint but perhaps not comforting for the individual woman who wants to know her own chances. Fortunately, there are certain factors that can make a difference in determining a woman's odds, according to a 2007 study from the National Institute of Child Health and Human Development. They include:
Body weight and age. Women who begin their pregnancies overweight or obese have less success when attempting VBACs. Odds of success also decline gradually with age; 40-somethings have lower success rates than do 20-somethings.
Ethnicity. Hispanic and African-American women face somewhat greater odds of needing a repeat C-section than non-hispanic white women, though researchers still haven't teased out why.
Size of baby. Carrying a very large baby—defined as a near-term fetus weighing more than 8 pounds, 13 ounces—drastically reduces a woman's chances of being able to deliver vaginally. ACOG advises doctors and women to also consider the birth weight of previous babies when planning for the delivery; moms who have given birth to 10-pound babies once are likely to do so again and should probably opt for a repeat cesarean. Interestingly, carrying twins doesn't nix a woman's chances of having a VBAC, according to recent studies, which overturns the conventional wisdom held by many doctors.
Previous pregnancy outcomes. If you've had a previous C-section because your labor failed to progress or your baby was in distress, chances are higher that you'll need a repeat cesarean. The same goes for women who have had a uterine rupture or a length-wise incision, often done in emergency C-sections. On the other hand, if you've already had a successful vaginal delivery, your odds are pretty high that you can have another.
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