Ask the Expert: VBACs — What You Need to Know

The phrase “once a Cesarean, always a Cesarean” is no longer valid due to a great increase in medical research and knowledge. These days, mothers are allowed more freedom of choice in their deliveries and vaginal births after Cesareans (VBACs) are becoming more common.

In order to determine if you are a candidate for VBAC, it is important that you discuss this option with your physician. Dr. Colleen McNally, an OBGYN affiliated with Sharp Mary Birch Hospital for Women & Newborns, answers frequently asked questions about VBACs.

What is a VBAC?
A VBAC, or vaginal birth after Cesarean, is when a mother delivers her baby vaginally after having previously delivered a baby via Cesarean, or C-section.

What factors make a woman want to consider a vaginal birth after a C-section? 
After considering the benefits versus the risks of a repeat C-section compared to a vaginal birth, you may decide VBAC is an option you want to explore. Of course, not every woman who has had a C-section wants a VBAC and that's OK. And, not every woman who has had a Cesarean section is a candidate for VBAC. If you're unsure about VBAC, talk with your physician to determine if a VBAC is a safe option for you. 

What are the benefits of a successful VBAC?
There are various benefits associated with a VBAC including:

• Able to breastfeed sooner after a vaginal birth compared to a C-section.
• A quicker recovery.
• Avoiding another incision in the uterus. Scarring is an important factor to consider if you are planning on another pregnancy. Placental problems can occur in 28 percent or more of women with more than two previous C-sections. These problems can result in hemorrhage and hysterectomy for the mother, and premature delivery of the baby.
• Infants born by mothers experiencing a C-section without labor may have a higher rate of breathing problems at birth.
• Mothers will have greater participation in the birth.

After reviewing your medical records, obstetrics history, personal risk factors and your current pregnancy complications, you and your doctor will discuss whether VBAC is right for you.

What are the risks associated with VBAC?
Vaginal birth after Cesarean section carries little risk for mother and baby, provided it is successful. In fact, 60 to 80 percent of women who attempt a VBAC have a successful vaginal delivery. A repeat Cesarean section, however, does carry more risks for the mother and a failed attempt at a VBAC carries increased risk for the baby.

There are various risks involved with attempting a VBAC including:

• An unsuccessful trial of labor that ends with a Cesarean delivery. Up to 28 percent of women who attempt VBAC develop a problem that requires a Cesarean delivery. A Cesarean after a trial of labor increases the risk of infection for both the mother and baby.
• A slight risk of uterine rupture (7 out of 1,000) can be a life-threatening risk for the mother and the baby. A uterine rupture is very rare yet very serious. Uterine rupture can be catastrophic and result in lack of oxygen delivery to the baby and subsequent neurological injury. There is a risk of death for the baby if the uterus ruptures during a VBAC, If the rupture cannot be repaired quickly, removal of the uterus (hysterectomy) may be necessary to prevent severe blood loss. Although it is not possible to predict that a woman will have a uterine rupture, there are known risk factors that can be identified:
  -An interval of less than 18 months between pregnancies
  -A mother who is obese
  -A previous classical or vertical uterine incision
  -Infant weighing more than 4,000 grams
  -Labor induction
  -Single layer closure for the initial Cesarean section
  -Two or more previous C-sections 

How do I know if I am eligible for a VBAC?
In order to attempt a VBAC, you will need to discuss the possibility with your physician because there are certain criteria you have to meet. VBAC eligibility depends on many factors, including:

• The reason for the prior C-section also matters. If the baby was breech or distressed, you may be a good candidate for VBAC. If the baby didn't fit through your pelvis or your cervix didn't dilate, the odds of a successful VBAC may not be as high. Don't take this as an absolute though. Every baby is different and every labor is different.
• The type of uterine incision that was used for your prior C-section. A low transverse incision (think bikini scar on your uterus) is strongest and least likely to open during another labor. If you aren't sure what type of uterine incision was used, check the operative report from your prior C-section.
• Whether your previous uterine incision was closed in one or two layers.
• You should have had no previous uterine rupture or uterine surgery such as removal of a fibroid deep in the uterine muscle and cavity. In addition, you cannot have any other medical condition that would make vaginal delivery dangerous. As a precaution, a physician and anesthesiologist must be available throughout your entire delivery in case you require an emergency Cesarean.

It's also important to keep in mind that some hospitals don't allow VBACs. Anesthesia must be available at all times in case a C-section becomes necessary, and not all hospitals can afford this luxury. Talk to your health care provider early in your pregnancy to make sure VBACs are allowed where he or she does deliveries. If not, you may need to change providers or hospitals if you want to pursue VBAC. Sharp hospitals do permit VBAC upon approval by your physician.

When are VBACs considered possible vs. not possible?
Questions about when a VBAC is advisable and when it is not should be directed to your medical provider. In July 2010, the American Congress of Obstetricians and Gynecologists released guidelines stating that all women with low transverse incisions — the most common type of Cesarean provided — should be allowed to attempt a VBAC, even if she’s had two prior Cesareans or is carrying twins.

For the most part, risks for VBAC are related to risk of uterine rupture. The risk of rupture is generally about 0.07 percent but can vary depending on the type of incision used on the prior Cesarean as well as interventions used during an attempted VBAC. Certain types of induction, for example, can increase the risk of uterine rupture. Questions about induction and pain medication during labor and their potential effects should be discussed with your provider. You should also ask your provider about the risks of repeat Cesareans, especially if you are planning for more children. Be sure you thoroughly understand the benefits and risks of both options when considering whether you may want to try a VBAC.

What kinds of exams and tests are used for VBAC?
Besides the usual prenatal tests, your doctor will determine if VBAC is a safe option for you by:

• Performing fetal heart monitoring during labor and delivery to watch for fetal distress. It can also help detect a sudden uterine rupture which is typically followed by a sudden and then ongoing drop in fetal heart rate. The mother might notice bleeding and pain.
• Reviewing your risks for uterine rupture and the chance of success for a trial of labor. Your physician will monitor your chance for success and your risks throughout your prenatal period and during labor.
• Reviewing your surgery records to verify the type of incision used for a previous Cesarean.

How can I best prepare my body and mind for trying for a VBAC?
The most important thing when seeking a VBAC is ensuring that everyone around you is supportive of your choice. This means finding a provider and a hospital or birth center that allows and is truly supportive of VBAC. Anyone present with you during your labor should be supportive of your choice, as well. If you decide you want to try for a VBAC, ask your doctor about his or her VBAC outcomes, and if you are working with a provider group, ask the same questions about the group as a whole since your own doctor may not be the one to attend your birth.

Also, it is important to understand that conditions may arise during pregnancy or labor that make it unsafe to proceed with a vaginal trial of labor after C-section. The health of you and your baby is the most important factor for the doctor caring for you.

For More Information
To learn more about Sharp's pregnancy and childbirth services or to find a Sharp-affiliated doctor, search for a San Diego OBGYN or call 1-800-82-SHARP (1-800-827-4277), Monday through Friday, 8 am to 6 pm. To find general information about pregnancy and childbirth, visit Pregnancy and Childbirth in Adult Health or read the Pregnancy and Childbirth News archive.