TOLAC and VBAC

Vaginal Birth After C-Section: How Should I Deliver if I’ve Had a Previous C-Section?

TOLAC AND VBAC

• Introduction
• History of TOLAC and VBAC
• What are some of the Benefits of VBAC?
• What are the Risks of VBAC?
• Risks of Attempting Vaginal Birth After C-Section
• Factors That Increase VBAC Success
• Factors That Decrease VBAC Success
• Rates of Successful VBAC Ater a Trial of Labor
• How Does Social Factors Affect My VBAC Success?
• When is a Repeat C-Section Best Rather Than a Trial of Labor?
• Uterine Incision Type
• Number of Previous C-sections
• Timing of Delivery
• Previous Myomectomy (fibroid surgery)
• Previous Uterine Rupture
• Where Should I Undergo my Trial of Labor After a C-Section?
• Can I Attempt a VBAC with Twins?
• What Can I do to Increase my Chance of a Successful VBAC?
• Is There a Way to Predict my Chances for a Successful VBAC?
• Summary

Introduction

So, you’ve had one or more prior Cesarean section (C-sections). Now it’s time to choose how you will deliver in your current pregnancy. A lot will go into this decision. But it is worth the effort to research and make an informed decision with your doctor on how best to proceed. After all, it is a major medical decision.

Before we go into depth, it’s vital to define TOLAC and VBAC. On one hand, TOLAC stands for a trial of labor after a C-section. Further, any woman that attempts a vaginal delivery after a prior C-section experiences a TOLAC.

On the other hand, VBAC means a vaginal birth after a C-section. To explain, a VBAC is a successful vaginal birth after a prior C-section. According to the National Institute of Child Health and Human Development (NICHD), a VBAC was a reasonable option for many women. In fact, about 60 % to 80% of candidates reported a successful VBAC.

Q: True or False: Once a C-section, always a C-section.

Answer: False.

History of TOLAC and VBAC

• • For most of the 20^th century, doctors believed that if you deliver by Cesarean section (C-section), all your future deliveries must also be by C-section.
  • However, studies from the 1960s suggested that this practice was pointless and possibly harmful. Plus, in 1980, a National Institutes of Health (NIH) Panel questioned the need for routine, repeat C-sections.
  • Between 1989 to 1996, more women had vaginal deliveries after a C-section instead of repeat C-sections.
  • Since 1996, C-section rates have been slowly increasing worldwide. In fact, between 1996 and 2008, the number of C-sections increased by 72%. However, a lot of these C-sections were not medically needed.
  • According to the Centers for Disease Control and Prevention, 32% of births were C-sections in 2015.
  • Still, this trend of rising repeat C-sections has no major maternal or perinatal benefits.

Q: True or False: A vaginal delivery is always safer than a C-section.

Answer: Mostly true. With rare exceptions, the safest way to have your baby is a vaginal delivery. Occasionally, the risk of a vaginal delivery outweighs the risk of having a C-section.

What are the Benefits of VBAC?

In most cases, a VBAC is not just less risky than a Cesarean delivery. But it has a lot of other pros. For instance, here are some benefits of a VBAC:

• • Avoid a major surgery.
  • Less risk of infection.
  • Shorter recovery time.
  • Less blood loss.
  • Less risk of blood transfusion.
  • Have a vaginal birth.
  • Less risk of blood clots forming in your legs or lungs.
  • Less risk of dying in childbirth.
  • Avoid future problems linked to more than one C-section.
  • Less risk bowel or bladder injury.
  • Less risk of future placenta problems.
  • Lower risk of hysterectomy.

What are the Risks of VBAC?

For women who have had a prior Cesarean delivery, there are three possible paths:

• • First, choose to have a repeat C-section (ERCD) without a labor trial. Then, schedule an elective repeat C-section in advance. Finally, attend before you go into labor.
  • Second, have a trial of labor that leads to a vaginal birth. Then get cleared to go into labor. And finally, have a vaginal birth after a C-section (VBAC).
  • Third, try for a vaginal birth but end up with a repeat C-section. Usually, this happens after a failed vaginal birth.

Both elective repeat C-section (path #1) and successful VBAC (path #2) are linked to some maternal and neonatal risks. But a failed TOLAC requiring a C-section (path #3) has the highest risk of problems.

The above information is from the largest study of its kind done by the National Institute of Child Health and Human Development of the National Institutes of Health (NICHD).

Risks of Attempting Vaginal Birth After C-Section

As expected, attempting vaginal birth after a C-section is risky. To be specific, here are some risks:

• • Uterine rupture.
  • Excessive bleeding (hemorrhage).
  • Maternal infection.
  • Blood clots in the legs or lungs.
  • Need for a hysterectomy.
  • Maternal death.
  • Lack of oxygen to the infant’s brain.
  • Infant death.

If your doctor shows concern about you having a trial of labor, it is best to take their advice. In this case, there is likely a high risk of a uterine rupture.

What is a Uterine Rupture?

In short, uterine rupture occurs when the scar on the uterus opens up during labor.

After a C-section, the uterine muscles are not as strong. As you go through labor, the muscles may not be strong enough to handle your contractions. Then, the uterine scar unravels. As a result, the rupture may cause the baby and perhaps the placenta to exit the uterus. Now, the baby is displaced from the uterus, floating around in your abdomen. As a result, a uterine rupture can be fatal for you and your baby.

Fortunately, a uterine rupture is the most well-known complication of TOLAC. But all uterine ruptures require an emergency or stat C-section. Sometimes the bleeding may be so severe that your Ob performs a hysterectomy.

Overall, the risk for fetal brain injury or death from uterine rupture during TOLAC is 1 in 2000 trials of labor. Thankfully, the overall rate of uterine rupture is only 0.7 percent. Plus, studies suggest that medicines to induce or speed up labor raise the chance for uterine rupture. This is because these medicines increase the force and length of uterine contractions. Oftentimes doctors only allow a trial of labor after a C-section if the labor is unplanned and without being induced with medicine.

Factors That Increase VBAC Success

Ultimately, the goal is to have a vaginal birth after prior Cesarean delivery. Although there is a risk of complications, there are a couple factors that increase your chances of a successful VBAC:

• • A prior successful vaginal birth.
  • A prior C-section for a non–recurring problem like breach baby or fetal distress.

Factors That Decrease VBAC Success

Now to discuss factors that decrease VBAC success:

• • Short Stature.
  • Overweight.
  • Medical illnesses like hypertension, diabetes, asthma, seizures, renal disease, thyroid disease, heart disease.
  • Prior trial of labor at a rural hospital.
  • Being past your due date.
  • A baby with an estimated weight of 8lbs, 13 oz (4kg), or more.
  • Induced or augmented labor.
  • Being under age 35.

Rates of Successful VBAC After a Trial of Labor

While there are many factors that decrease the success rate of a VBAC, there is good news. For example, here are a few statistics about successful VBACs:

• • According to recent studies, 94% of women have a successful VBAC if they had a prior VBAC.
  • Further, 83% of women have a successful VBAC if they had a vaginal birth before their C-section.
  • Finally, 63% of women have a successful VAC if they have no history of a prior vaginal birth.

Ultimately, the more often you have a successful VBAC, the higher your chances for a successful trial of labor after a C-section.

How Do Social Factors Affect My VBAC Success?

In the US, married women and non-Hispanic white women have the highest rates of successful vaginal births after a C-section. Yet, ethnicity, race, and marital status are social and not physiological constructs. So, having a spouse and being born into a particular race does not affect our body’s dynamics in the labor process.

Rather the greater success rate for married, non-Hispanic white women reflects the biases of the healthcare system. In fact, health care providers may offer more patience and leeway to certain groups to increase their VBAC success rate. As these biases resolve, these differences in results will go away.

When is a Repeat C-Section Better Than a Trial of Labor?

In general, many factors will impact this decision. For instance, some factors include

• • The type of incision made on the uterus.
  • The timespan between your current pregnancy and prior C-section.
  • Your surgical history.

Uterine Incision Type

In most cases, your doctor uses the type of uterine incision to decide between a trial of labor or a scheduled elective C-section before your labor starts. Specifically, there are three types of uterine incisions used for C-sections, listed from lowest to highest risk of uterine rupture:

• • Low Transverse C-Section: a side-to-side cut made across the lower, thinner part of the uterus (most common, least risk)
  • Low Vertical Uterine Scar: an up-and-down cut made in the lower, thinner part of the uterus (medium risk)
  • High Vertical (or “Classical”) Uterine Scar: an up-and-down cut made in the upper part of the uterus (highest risk). Oftentimes, doctors perform classical incisions to deliver preterm babies. Usually, this type of incision is the most risky. If you have had a prior classical C-section, you should never labor. Once a doctor performs a classical C-section, they tell you and a family member that all future deliveries must be C-sections.
  • Unknown Uterine Incision Type: the result of the doctor managing your labor not having access to your prior operative report. As a result, the doctor does not know the type of incision made on your uterus. In this case, they advise a repeat C-section versus trial of labor based on your history.

In summary, low segment transverse incisions are the most common and have the lowest risk of uterine rupture. While classical incisions have the highest risk of uterine rupture. In fact, the risk of rupture is so high that patients with a prior classical incision should NEVER labor. Finally, a low vertical uterine incision may have a trial of labor or a repeat C-section. However, this depends on patient and doctor comfort levels. Plus, if you had a preterm baby via C-section, the uterine incision type would be less certain without your operative record.

Number of Previous C-sections

In general, the most common type of patient offered a trial of labor after a C-section is one who has had one prior low segment transverse uterine scar. With two prior C-sections, less doctors are likely to offer you a trial of labor. Sadly, there is little information on women with more than two C-sections experiencing a trial of labor. In most cases, doctors advise a repeat C-section for all future pregnancies if you have had two C-sections.

Timing of Delivery

If your prior C-section is less than 18 months from your delivery date, your doctor will advise a repeat C-section. This is because your uterus would not have enough time to heal. So, the uterine scar will not be strong enough to hold up to the labor process.

Previous Myomectomy

Having a history of fibroids surgery will affect whether your doctor advises a C-section or a trial of labor. Plus, removal of multiple large fibroids usually requires extensive dissection into your uterus. In this case, most doctors would advise an elective repeat C-section. Ultimately, you and your doctor will discuss and decide the best option for you and your baby.

Previous Uterine Rupture

If you have had a prior uterine rupture, the medical community agrees that you should never labor again. Further, all future pregnancies should be delivered by a C-section before your labor starts.

Where Should I Undergo my Trial of Labor After a C-Section?

In general, the number one criteria when deciding where to undergo a trial of labor after a C-section is based on the answer to this question:

Can an emergency C-section be performed if needed? 

If yes, then that venue is an acceptable location to experience a trial of labor. However, home births and birthing centers are not appropriate venues to undergo a trial of labor after a C-section.

Can I Attempt a VBAC with Twins?

If both babies are head down, then the answer is yes. But not all doctors will agree to managing twins in a trial of labor. So, it is vital to find a doctor that is comfortable with this setup early in your pregnancy. Usually, doctors advise a C-section for triplets.

What can I do to Increase my Chance of a Successful VBAC?

• • First, talk with your doctor about VBAC early in your pregnancy. It is vital to ensure that the hospital managing your labor can support you in a VBAC attempt. At the very least, they should be ready to handle emergency C-sections with an available anesthesiologist.
  • Second, control your weight. According to a 2013 study published in the American Journal of OB/GYN, women with normal pre-pregnancy weight experienced higher failure rates with increased weight gain. So, talk with your doctor about how to lose weight before you become pregnant. Plus, manage your diet and weight during your pregnancy. And become or stay active during pregnancy.
  • Finally, be patient. If you go into labor on your own, your chance for a successful VBAC increases. In fact, a VBAC using oxytocin (Pitocin) is 10% more likely to fail. Further, there was a similar trend with prostaglandins. In addition, the risk of uterine rupture rises with induction. On average, the risk of uterine rupture is 0.7 percent. But that risk increases to as high as 1 percent with the use of Pitocin. While it increases to 1.8 percent with prostaglandin.

Is there a way to predict my chances for a successful VBAC?

Sometimes, women with singleton pregnancy can use a VBAC calculator to figure out their risk of having a successful VBAC. But keep in mind that VBAC calculators are not always true. Usually, they are calculated based on outcomes among study participants.

If your predicted chance of vaginal birth after a C-section is:

• • Less than 60%, then consider a repeat C-section.
  • 60-70%, then an attempt at VBAC may be helpful.
  • Greater than 70%, it is reasonable for you to attempt a VBAC.

Summary

Ultimately, the decision of whether to attempt a vaginal birth or have a repeat Cesarean section must be made carefully by you and your doctor. So, discuss your concerns and goals with your doctor at your first prenatal visit. And ensure they have records of your operative note from your prior C-section and any other uterine procedures. Finally, your doctor should fully review the risks, benefits, and options of both a trial of labor after a C-section and an elective repeat C-section.

Copyright: myObMD Media, LLC | Written by: Lisa Shephard, MD| Edited by: Dayna Smith MD |August 30, 2021.