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Risks Of Vaginal Birth After Cesarean (VBAC): 6 Factors To Consider

Vaginal Birth After Cesarean Delivery (VBAC)

If you’re due to deliver soon and have had a C-section before, some comforting statistics should make you feel better about a vaginal birth after cesarean (VBAC). While risks of uterine rupture exist, the odds aren’t worse than when having multiple C-sections. What’s best depends on your health, age, and pregnancy complications if any.

Giving birth the traditional way without surgical intervention may be something you have always wanted. But if a medical emergency, the position of the baby, or some other complication of the pregnancy meant that you had a cesarean section previously, how does that affect future pregnancies? If you’re wondering about risks associated with a vaginal birth after cesarean (VBAC), you are not alone. According to the Centers for Disease Control and Prevention (CDC), nearly a third of all births in the United States are via cesarean or C-sections, making this a matter of concern for a lot of women as they plan their next baby.1

1. VBAC May Pose Risks For Both Baby And Mother

What you need to start with is an awareness that a VBAC is not without its own risks. Here’s a look at some of them.

Risk of Uterine Rupture

One of the biggest concerns around VBAC stems from the possibility of having a uterine rupture. This may happen if your old cesarean scar on the uterus breaks open due to the effort of labor and the strain of a vaginal delivery. Should this happen, it can be potentially life-threatening to you and your baby and is best avoided if you are considered at high risk of rupture.2

About 1 in 300 or 0.35% of VBAC labors results in uterine rupture. Your doctor or an experienced midwife can monitor the progress of delivery to check for abnormalities like pain between contractions, bleeding, or changes to your heartbeat or your baby’s that can warn of a potential complication or rupture during VBAC. They will switch to a cesarean if they suspect a possible rupture.3

For most women, however, the risk is not high. In fact, if you’ve had a low transverse incision or “bikini cut” in your earlier pregnancies, the risk of having a uterine rupture while attempting a vaginal delivery is as low as 0.2% to 1.5%.4 This type of cut tends to bleed less than other types of incisions and results in scar tissue that is stronger, making your uterus less likely to have a tear.5

Increased Risk of Bleeding And Infection From Emergency Cesarean Section

If your VBAC goes wrong midway, your doctor may need to perform an emergency cesarean section. Unfortunately, this is associated with greater risk of bleeding as well as a higher chance of your contracting an infection from the procedure.6

Slightly Higher Mortality Risk To The Baby

The Royal Australian and New Zealand College of Obstetricians and Gynecologists also caution that the risk of brain damage or death for a baby is marginally higher if you opt for a VBAC than if you choose to opt for a repeat cesarean section.7

Overall, fetal mortality rates as well as perinatal and neonatal (before and after birth) mortality rates are lower in women who opt for elective repeat cesarean section delivery than in those who choose to attempt a VBAC and go through labor as with a normal vaginal birth (trial of labor).8 However, maternal risk is lower for trial of labor, the precursor to VBAC, than for elective repeat cesarean delivery.9

2. Obesity, Preeclampsia, And Other Factors Make VBAC Risky For Moms-To-Be

If you are someone with prior instances of uterine rupture, someone who has had uterine surgery, or have pregnancy complication or health problems like heart disease, diabetes, placenta previa, or genital herpes, a cesarean section may be your only option, so go with what your doctor suggests or get a second doctor’s opinion if you like.10

There are also some factors that might make it risky for you to opt for VBAC. Remember, the risk varies from woman to woman, but these are broad criteria that might make a VBAC more risky for some. Do any of these hold true for you? 11 If you answer “yes” to one or more, that may raise your risk.

  • You have had more than 2 low transverse c-section deliveries or you’ve had a rupture or other problems in a previous delivery.12
  • Your labor has to be induced/you are past your due date.
  • You are obese.
  • You have preeclampsia, a condition that results in high blood pressure, vision problems, headaches, protein in the urine, and problems with your liver/kidney.
  • The gap between your last pregnancy and this one (interpregnancy interval) is less than 19 months.
  • Your birth location isn’t equipped to do an emergency cesarean section should you need one midway through a VBAC attempt.

3. But VBAC Is Still Less Risky Than Multiple C-Sections For Many Moms

If you have two or more previous low transverse incision cesarean deliveries, you may still be able to opt for VBAC if a senior obstetrician okays it. They will discuss all possible risks with you and make the necessary arrangements for added safety during the birth – like standing by for an emergency cesarean section.13

If you are medically in the clear but are considering having repeat cesarean deliveries to reduce the risk of a ruptured uterus or other complications, the data may surprise you. According to a report by the CDC, women undergoing repeat cesarean deliveries actually have the highest rates of ruptured uterus as well as of unplanned hysterectomies, while those who opt for VBAC deliveries have lower rate of maternal morbidities like the need for maternal transfusion, ruptured uterus, unplanned hysterectomy, and admission to the intensive care unit (ICU). In fact, the risk of ICU admission and transfusion is even lower among women with VBAC than those undergoing primary cesarean delivery. Which means, if you are cleared to have a VBAC, you are actually going to face fewer risks than when you had your first cesarean section!14

4. 90% Of Women With Prior Cesarean Sections Are Eligible For Vaginal Births

Are you still wondering if a previous cesarean section automatically eliminates you from the option of a vaginal birth and labor the traditional way? It doesn’t have to. In fact, as many as 90% of women who have delivered an earlier baby via cesarean section are possible candidates for VBAC. Of those who are cleared to opt for the labor and vaginal delivery route, 60 to 80% on average are able to successfully give birth this way.15

According to one piece of research, 85% of those opting for VBAC could successfully have their babies by this route, while 15% needed to undergo repeat emergency cesarean sections when vaginal delivery failed. There was no mortality associated with this, either among the babies or the mothers.16 So the odds aren’t too bad if you do choose VBAC.

5. Vaginal Delivery Has Some Advantages Over Multiple Cesarean Sections

There are reasons why women choose to opt for VBAC or vaginal deliveries in general. Here’s a look at some benefits from this:17

According to some studies, the success of rate of VBAC in twin pregnancies was similar to those singleton pregnancies. Of course, the other criteria impacting the risk or possibility of success like maternal health, age, and so on, still apply.18

  • No surgery involved
  • Faster recovery
  • Lower infection risk
  • Lower blood loss

In addition, having a VBAC lowers your risk from other complications that can arise for women with multiple cesarean sections in future pregnancies. So if you’re going to grow your family more after this baby you have on board, you may want to consider these too. Multiple cesarean sections are linked to:

  • Greater risk of bowel/bladder injury
  • Possible complications with the placenta in future pregnancies
  • Greater risk of a need for hysterectomy

6. Some Factors May Improve Your Eligibility For VBAC

Remember, even if your mind is set on a VBAC, certain factors could help or hinder your cause. Here are some things that could make you eligible for VBAC and less at risk from this.

  • If the reason you had the cesarean section in the previous pregnancy is not present now.19
  • If you do not have any additional uterine scars, any anomalies, or prior ruptures, you should be fine to have VBAC.20
  • If you are in otherwise good health.21
  • If your baby is normal sized.22 If your baby weighs over 3 kg, a VBAC is less likely to be successful and you may wind up needing a cesarean section.23
  • If the baby is in the right position, head down, for a vaginal delivery.24
  • If your cervix is dilated to 3 cm or more when you are admitted, you are more likely to have a successful VBAC.25
  • If you go into labor on your own before your due date.26
  • If your doctor and team are available at hand to monitor your progress through labor and to decide if you need a cesarean at some point.27

In addition to these pregnancy-related factors, your age, height, and weight also matter. According to the Royal College of Obstetricians and Gynaecologists, these factors increase chances of success for a VBAC:28

  • Greater maternal height
  • Maternal age of under 40 years
  • BMI of under 30

Remember, you may not always have a choice in opting for a VBAC. If your doctor recommends a C-section because it is likely to be safer for you and your baby, don’t fight the decision. They will have considered the odds and assessed your overall medical condition to arrive at this decision. Go with the flow.

So you can lay to rest any fears stemming from that old adage of “once a cesarean section, always a cesarean section,” because as the numbers reveal, it really doesn’t have to be that way. Discuss your options with your doctor, express your desire to opt for a VBAC, and then do all you can to make the process as safe for you and your baby as you can.

References   [ + ]

1. Births – Method of Delivery. Centers for Disease Control and Prevention.
2. Vaginal Birth After Cesarean Delivery. American College of Obstetricians and Gynecologists.
3. VBAC: Vaginal birth after caesarean. NCT First 1,000 Days.
4, 12, 15, 19, 20, 21, 22, 24, 27. VBAC: Vaginal Birth After Cesarean. American Pregnancy Association.
5, 10, 11, 26. Vaginal Birth After Cesarean. March of Dimes.
6, 7. Vaginal Birth After Cesarean Section. The Royal Australian and New Zealand College of Obstetricians and Gynecologists.
8, 9. Vaginal Birth After Cesarean: New Insights. Agency for Healthcare Research and Quality, U.S. Department of Health and Human Services.
13, 28. Birth After Previous Caesarean Birth. Royal College of Obstetricians and Gynaecologists.
14. Curtin, Sally C., K. D. Gregory, L. M. Korst, and S. F. Uddin. “Maternal Morbidity for Vaginal and Cesarean Deliveries, According to Previous Cesarean History: New Data From the Birth Certificate, 2013.” National vital statistics reports: from the Centers for Disease Control and Prevention, National Center for Health Statistics, National Vital Statistics System64, no. 4 (2015): 1-13.
16, 23, 25. Bangal, Vidyadhar B., Purushottam A. Giri, Kunaal K. Shinde, and Satyajit P. Gavhane. “Vaginal birth after cesarean section.” North American journal of medical sciences 5, no. 2 (2013): 140.
17. Vaginal Birth After Cesarean Delivery. American College of Obstetricians and Gynecologists.
18. Birth After Previous Caesarean Birth. Royal College of Obstetricians and Gynaecologists.

Disclaimer: The content is purely informative and educational in nature and should not be construed as medical advice. Please use the content only in consultation with an appropriate certified medical or healthcare professional.