Study Claims VBAC is Less Safe Than C-Section. Here's What You Need to Know.
A new study claims that attempting a vaginal birth after a previous c-section (VBAC) is less safe than having a subsequent c-section. The absolute risk of complications was low—1.8% among attempted VBACs and 0.8% among people who had c-sections. Nevertheless, the media has already pointed to the study as a reason to limit access to VBACs. The data offers more fuel to providers who would deny pregnant people choices, too. Digging deeper into the data, it becomes clear that this study is not a reason for pregnant people who otherwise would have attempted a VBAC to have a c-section. Here’s what you need to know.
What the study found
The study compared birth outcomes among 74,043 people who gave birth in Scotland between 2002 and 2015. All of the study participants had at least one prior c-section. 45,579 gave birth via planned c-section, compared to 28,464 who attempted a vaginal birth. 8,083 of the attempted VBACs ended in an emergency c-section—a VBAC success rate of 71.6%.
The overall risk of complications to both mother and baby increased slightly with a planned VBAC. The most prevalent complications were:
Uterine rupture: 0.24% of attempted VBACs vs. 0.04% of scheduled c-sections.
Blood transfusion: 1.14% of attempted VBACs vs. 0.5% of scheduled c-sections.
Puerrperal sepsis: 0.27% of VBACs vs. 0.17% of scheduled c-sections.
Surgical injury: 0.17% of VBACs vs. 0.09% of scheduled c-sections.
Perinatal injury rates were also higher with VBAC attempts.
The study did find some benefits associated with attempting a VBAC. Women who attempted a VBAC were more likely to initiate breastfeeding and more likely to breastfeed at 6-8 weeks postpartum.
Additionally, women who had a VBAC were significantly less likely to be readmitted to the hospital within 42 days of birth. This suggests that women who had scheduled c-sections may have experienced additional complications that the study did not capture. In the U.S., the 42-day postpartum period is the time of highest mortality and greatest complications.
Attempted VBACs also mean shorter hospital stays, on average.
What the study did not find
People giving birth deserve comprehensive information, not just cherry-picked data. Even when a woman strongly supports VBAC, it is important for her to know the risks. It’s equally important to not inflate those risks.
The study did not look at all possible risks associated with c-section. In medical circles, it’s common to look only at short-term complications such as infection and bleeding. Yet many people choose VBACs because of concerns about long-term complications.
Research consistently finds that c-sections are associated with a higher risk of postpartum mood disorders. When a vaginal birth is important to a woman, the risk may further increase. And when a woman is coerced or forced into a c-section based on a faulty reading of a single study, she may develop PTSD or other trauma-related symptoms.
A prior c-section also increases the risk of complications with subsequent deliveries. Placenta accreta is one of the most dangerous pregnancy complications, with a higher mortality rate than any other pregnancy complication. Most women with this condition need a blood transfusion following birth. Many must stay in the hospital for weeks or months. About 7% die. Each c-section increases a woman’s risk of having placenta accreta with her next pregnancy. Indeed, the rising c-section is the primary factor driving the rising placenta accreta rate.
Uterine rupture, hemorrhage, and infection are serious complications that researchers absolutely must measure. But no single study can take into account all potential risks of any method of giving birth. This means that no single study can prove that VBACs are safe or unsafe. People giving birth must instead weigh their own risk tolerance, look at their risk factors, and consult with providers who are willing to be honest about the data—not use scare tactics or blindly promise that any particular delivery choice is always safer.
Putting the Data in Context
Any death, hemorrhage, or other serious complication is one too many. But the absolute risk of complications following attempted VBAC is low. Lower still is the risk of serious, lasting harm or death following birth complications. Twenty babies died—either due to stillbirth or neonatal death—following an attempted VBAC. That’s 0.07% of the total, or a death risk of about 7 in 10,000. Following a planned c-section, 5 babies died. That’s 0.01% of the total, for a total death risk of about 1 in 10,000.
This means that doctors who say that VBAC will kill a baby or is guaranteed to cause complications—a common coercive tactic—are grossly misleading women.
There’s another important issue here: emergency vs. elective c-section. Emergency c-sections are inherently riskier for many reasons: the surgeon may be less prepared or skilled; the woman may be suffering another complication at the time of surgery; there are more anesthesia complications; there may be a rush to get the baby out, putting both the woman and baby in danger.
Women who attempt VBACs have emergency c-sections, not scheduled ones. So some of the risk here comes from the risk inherent to emergent surgery, not vaginal birth. The study found that for women who have a successful VBAC, the risk of several complications—including hysterectomy and surgical injury—is much lower. The risk of uterine rupture is only slightly higher.
Is the study relevant to American maternal mortality?
The biggest shortcoming of this study is that it occurred in Scotland. The maternal mortality rate in the United Kingdom is 9 per 100,000. In the U.S., maternal mortality is nearly three times that rate, at 23 per 100,000. Georgia’s maternal mortality rate is higher still, at 46 per 100,000. The data consistently show that this is not because of something fundamentally different about American women. American maternity care is worse. We have higher c-section rates, higher rates of medical error, and most maternal deaths are preventable.
C-sections are a key piece of this puzzle. Doctors in the U.S. routinely recommend medically unnecessary c-sections, then fail to properly treat complications. In Scotland, pregnant people may be able to rely on receiving competent care. In the U.S., every birth—vaginal or surgical—is potentially life-threatening. So rather than looking at large data sets, women should instead consider their providers, their hospital, and their risk factors.
Making the decision
A 1% difference in risk is not a reason to force women into c-sections or to refuse to attend vaginal births—particularly when that figure does not take into account all potential risks. But it is a number birthing people must be mindful of.
When deciding whether or not to have a c-section or VBAC, some important questions to ask include:
What is your VBAC success rate?
What is your rate of surgical complications?
What can I do to minimize my risk?
What are my specific risk factors for each birth option?
If a provider overstates the risk of VBAC, find someone else. You can’t trust a provider who is incapable of reading scientific research. Likewise, if a provider promises that VBAC is always safer, it’s time to find someone else. The truth lie somewhere in between. And ultimately, the birthing person calls the shots. Any provider who does not understand this is not worth your time.