Vaginal Birth After Cesarean (VBAC) Guide

Considering a vaginal birth after a previous cesarean delivery? This guide explains what VBAC is, who is a good candidate, the benefits and risks, and what to expect during a trial of labor after cesarean (TOLAC).

Published: October 27, 2023•Updated: October 27, 2023

Understanding Vaginal Birth After Cesarean (VBAC)

If you've had a cesarean delivery (C-section) in the past, you might be wondering about your options for future births. One important option is a Vaginal Birth After Cesarean (VBAC). This guide is here to help you understand VBAC, its benefits, risks, and what to discuss with your healthcare team.

What is VBAC and TOLAC?

It's helpful to understand two key terms:

Vaginal Birth After Cesarean (VBAC): This is when you successfully give birth vaginally after having had at least one previous C-section.
Trial of Labor After Cesarean (TOLAC): This is the attempt to have a vaginal birth after a previous C-section. A TOLAC can lead to a successful VBAC, or it might result in an unplanned repeat C-section if a vaginal birth isn't possible or safe.

In the UK, this is often referred to as 'Birth After Previous Caesarean Birth'.

Am I a Candidate for VBAC?

Deciding if VBAC is right for you involves a careful discussion with your doctor, who will review your medical history and current pregnancy. The goal is to assess your likelihood of a successful VBAC and the potential risks.

Who is generally a good candidate?

Most guidelines agree that the ideal candidate has:

One previous low-transverse cesarean delivery (this is the most common type of C-section incision, made horizontally across the lower part of your uterus).
No other medical reasons that would prevent a vaginal delivery (like placenta previa).

When might VBAC not be recommended?

There are certain situations where a TOLAC is generally not advised due to increased risks:

Previous uterine incision type: If your prior C-section involved a 'classical' (vertical) incision, a T-shaped, J-shaped, or other extensive uterine surgery, a TOLAC is usually not recommended due to a significantly higher risk of uterine rupture.
Prior uterine rupture: If you have experienced a uterine rupture in a previous pregnancy.
Any other contraindication to vaginal delivery: Such as placenta previa (where the placenta covers the cervix).

Special Considerations

Some situations require more detailed discussion and careful assessment:

More than one previous C-section: While ACOG (American College of Obstetricians and Gynecologists) suggests TOLAC can be a reasonable option for some patients with two prior C-sections, they note that data is limited and the risk of uterine rupture is higher (around 1.7%). The RCOG (Royal College of Obstetricians and Gynaecologists) advises more caution and individualized assessment, recommending management in a unit with immediate access to emergency C-section and advanced resuscitation.
Unknown uterine scar: If your previous operative report is unavailable, TOLAC may still be an option if there's a strong suspicion that your incision was low-transverse.
Twin pregnancy: TOLAC can be considered if you are carrying twins.
Expecting a large baby (macrosomia): While TOLAC can be considered, success rates may be lower, and risks might be slightly higher.

How is candidacy assessed?

Your healthcare provider will look at:

Your medical history: Reviewing your previous C-section operative report is crucial to confirm the type of uterine incision. They'll also consider the reason for your previous C-section(s), any other uterine surgeries, and if you've had a prior uterine rupture.
Current pregnancy details: Such as whether you're carrying one baby or multiples, and the baby's position.
Physical examination: To assess your pelvis and estimate your baby's weight.
Ultrasound: To confirm fetal presentation, estimate weight, and check for any contraindications.

Understanding Your Chances of Success and Influencing Factors

For those who attempt TOLAC, approximately 60-80% will have a successful VBAC. Several factors can influence your likelihood of success:

Factors that increase your chances of a successful VBAC:

Prior vaginal delivery: Especially if you've had a successful VBAC before, your success rate can be as high as 85-90%.
Spontaneous onset of labor: Going into labor on your own.
Non-recurring reason for your previous C-section: For example, if your C-section was for a breech baby or placenta previa, rather than issues with labor progression.
Favorable cervix: Your cervix is already starting to soften and open when you're admitted to the hospital.

Factors that may lower your chances of a successful VBAC:

Recurrent reason for initial C-section: If your previous C-section was due to labor dystocia (difficult labor) or 'failure to progress'.
Increased maternal age.
High Body Mass Index (BMI): Especially if your BMI is over 30 or 40.
High neonatal birth weight: If your baby is estimated to be very large (over 4000g or 4500g).
Gestational age over 40 weeks.
Short time between deliveries: Less than 18-24 months since your last C-section.
Preeclampsia.
Induction of labor: Compared to spontaneous labor.
No prior vaginal delivery.

Some of these factors, like the time between pregnancies and your pre-pregnancy BMI, are modifiable, meaning you can discuss them with your doctor to optimize your health.

What Happens During a Trial of Labor (TOLAC)?

If you decide to proceed with a TOLAC, your care will be carefully managed to ensure the safety of both you and your baby.

Where will I give birth?

TOLAC should always take place in a hospital facility that is fully equipped to perform an emergency C-section immediately, with medical staff readily available around the clock.

Monitoring during labor

Continuous electronic fetal monitoring (EFM) is recommended throughout your labor. This allows your healthcare team to closely watch your baby's heart rate, which is crucial for detecting any signs of distress early.

Pain management

You can still have pain relief options, such as an epidural, during a TOLAC. It is not contraindicated.

Induction or augmentation of labor

While spontaneous labor is preferred, induction or augmentation (speeding up labor) can be considered. However, it's important to know that these methods are associated with an increased risk of uterine rupture compared to spontaneous labor.

Oxytocin: Can be used cautiously to induce or augment labor.
Prostaglandins: Misoprostol (PGE1) is generally contraindicated for cervical ripening in patients with a prior C-section due to a high risk of uterine rupture (ACOG). Other prostaglandins like PGE2 may be used with caution (RCOG).
Mechanical methods: Methods like a Foley balloon catheter are considered safer options for cervical ripening.

Your labor will be managed according to standard protocols, but with a heightened awareness for any potential complications.

Risks and Benefits of VBAC

Understanding the potential risks and benefits is key to making an informed decision.

The most significant risk: Uterine Rupture

Uterine rupture is the most serious complication of TOLAC. This is when the scar from your previous C-section tears during labor. While serious, it is rare.

Incidence: For women with one prior low-transverse C-section, the risk is approximately 0.5-0.9% (about 1 in 200 to 1 in 100).
Increased risk: The risk increases with factors like induction of labor or having had more than one previous C-section.

Emergency Signs of Uterine Rupture (Red Flags)

It's important for your care team to be vigilant for signs of uterine rupture. These can include:

Fetal heart rate abnormalities: Most commonly, a sudden drop in the baby's heart rate (fetal bradycardia) is the most frequent and often earliest sign.
Sudden or severe abdominal pain: Especially pain that persists between contractions.
Loss of fetal station: The baby's head or presenting part moves up in the pelvis instead of down.
Change in uterine contraction pattern: For example, contractions suddenly stopping.
Less common signs can include vaginal bleeding (which might be minimal), maternal low blood pressure or fast heart rate, blood in urine, or shoulder tip pain.

Uterine rupture can sometimes be subtle or even asymptomatic, so a high index of suspicion is always maintained by your medical team.

Maternal Complications

Successful VBAC: Generally associated with the lowest rates of complications like hemorrhage (heavy bleeding), infection, and blood clots compared to both a planned repeat C-section and a failed TOLAC.
Failed TOLAC: If your trial of labor doesn't result in a vaginal birth and you need an unplanned C-section during labor, this carries the highest rates of maternal complications, including higher risks of hemorrhage, infection, and surgical injury.
Planned Repeat C-section (ERCD): Has lower morbidity than a failed TOLAC but higher morbidity than a successful VBAC.
Other risks: Risks like hysterectomy (removal of the uterus), surgical injury, and blood transfusion are generally higher with TOLAC (especially if it fails) compared to a planned repeat C-section.

Neonatal Complications

Perinatal death: The overall risk is low for both TOLAC and planned repeat C-sections. However, the risk of intrapartum (during labor) or neonatal death is slightly higher with TOLAC (specifically related to uterine rupture) than with a planned repeat C-section. For low-risk women with one prior C-section, the perinatal mortality rate is about 1.3 per 1,000 for TOLAC versus 0.5 per 1,000 for ERCD (ACOG).
Hypoxic-Ischemic Encephalopathy (HIE): The risk of this brain injury due to lack of oxygen is significantly increased in the rare event of a uterine rupture.
Transient Tachypnea of the Newborn (TTN): This temporary breathing difficulty in newborns is actually lower with TOLAC/VBAC compared to a planned repeat C-section.

Long-Term Benefits of VBAC

Choosing VBAC can have important long-term benefits, especially if you plan to have more children:

Avoids risks of multiple C-sections: Each C-section increases the risk of complications in future pregnancies, such as placenta previa (placenta covering the cervix) and placenta accreta spectrum (placenta growing too deeply into the uterine wall), which can cause life-threatening hemorrhage. VBAC helps avoid these escalating risks.
Faster recovery: A successful vaginal birth typically leads to a quicker recovery and shorter hospital stay compared to a C-section.

Making Your Decision

The decision to attempt a VBAC or schedule a repeat C-section is a very personal one. It's important to have an open and honest conversation with your healthcare provider about your individual circumstances, preferences, and concerns. They will help you understand your specific chances of success and the risks involved, allowing you to make the best choice for you and your baby.

Preventing Primary Cesarean Deliveries

While this guide focuses on VBAC, it's worth noting that preventing the first C-section when it's not medically necessary is the most effective way to avoid the risks associated with both TOLAC and repeat C-sections. Strategies include careful management of labor, using external cephalic version for breech babies, and appropriate use of operative vaginal delivery when indicated.

Frequently Asked Questions

What is the difference between TOLAC and VBAC?

TOLAC (Trial of Labor After Cesarean) is the attempt to have a vaginal birth after a previous C-section. VBAC (Vaginal Birth After Cesarean) is the successful outcome of that attempt – meaning you actually give birth vaginally.

What are my personal chances of having a successful VBAC?

Your personal chances depend on many factors, including the reason for your previous C-section, whether you've had a vaginal birth before, your age, BMI, and how your current labor progresses. Generally, 60-80% of women who attempt TOLAC have a successful VBAC. Your doctor will discuss your specific situation with you.

What is a uterine rupture and how likely is it to happen to me?

Uterine rupture is a rare but serious complication where the scar from your previous C-section tears during labor. For women with one prior low-transverse C-section, the risk is approximately 0.5-0.9% (about 1 in 200 to 1 in 100). This risk can increase with certain factors like labor induction or having had more than one C-section.

What are the signs of a uterine rupture during labor?

The most common and often earliest sign is a sudden, significant change in your baby's heart rate, usually a drop (fetal bradycardia). Other signs can include sudden or severe abdominal pain that doesn't go away between contractions, the baby moving up in the pelvis instead of down, or a change in your contraction pattern. Your medical team will be closely monitoring for these signs.

What happens if my uterus ruptures?

If a uterine rupture is suspected, an immediate emergency C-section is performed to ensure the safety of both you and your baby. This is why TOLAC is only recommended in facilities with immediate access to emergency surgical care.

What are the specific risks of a trial of labor for me and my baby?

For you, the main risk is uterine rupture, which can lead to severe bleeding, infection, or in rare cases, hysterectomy. If TOLAC fails and you need an unplanned C-section during labor, your risk of complications like infection and hemorrhage is higher than with a planned repeat C-section or a successful VBAC. For your baby, the main risk is related to uterine rupture, which can lead to oxygen deprivation and, in rare cases, serious complications like brain injury or perinatal death.

What are the specific risks of a planned repeat C-section for me and my baby?

For you, a planned repeat C-section carries risks such as infection, bleeding, longer recovery time, and surgical complications. In future pregnancies, multiple C-sections increase the risk of conditions like placenta previa and placenta accreta spectrum. For your baby, risks include a slightly higher chance of temporary breathing difficulties (Transient Tachypnea of the Newborn) compared to a vaginal birth.

What are the benefits of a successful VBAC?

A successful VBAC typically means a shorter recovery time, less pain after birth, lower risk of infection and hemorrhage, and avoiding the risks associated with multiple C-sections in future pregnancies (like placenta accreta spectrum).

Am I a good candidate for TOLAC?

The best candidates usually have had only one previous low-transverse C-section and no other medical reasons preventing a vaginal birth. Your doctor will review your specific medical history, including the reason for your previous C-section and the type of uterine incision, to determine if TOLAC is a safe option for you.

Can I have a VBAC if my first C-section was for 'failure to progress'?

Yes, you can still consider VBAC, but your chances of success might be slightly lower compared to someone whose previous C-section was for a non-recurring reason (like a breech baby). Your doctor will discuss this factor as part of your overall assessment.

Can I have a VBAC after two or more C-sections?

This is a more complex situation. While some guidelines (like ACOG) suggest it can be a reasonable option for certain patients, the risk of uterine rupture is higher (around 1.7%). Other guidelines (like RCOG) advise more caution and individualized assessment, recommending care in a highly equipped facility. You'll need a thorough discussion with your doctor about the increased risks and benefits.

Do I need to know what kind of uterine scar I have? How can I find out?

Yes, knowing your uterine incision type is very important. A low-transverse incision carries the lowest risk. You can find this information in your previous C-section operative report. Your doctor can help you obtain this record if you don't have it.

Can I be induced if I want to try for a VBAC?

Induction of labor can be considered, but it is associated with an increased risk of uterine rupture compared to going into labor spontaneously. Your doctor will discuss the risks and benefits of induction methods with you.

What methods of induction are safest for TOLAC?

Mechanical methods, such as a Foley balloon catheter, are generally considered safer for cervical ripening in TOLAC. Certain prostaglandins, like misoprostol (PGE1), are contraindicated due to a high risk of uterine rupture. Oxytocin can be used cautiously.

Can I have an epidural during my trial of labor?

Yes, epidural analgesia is not contraindicated and can be used for pain management during a TOLAC.

What kind of monitoring will be required during my labor?

Continuous electronic fetal monitoring (EFM) is recommended throughout your labor to closely track your baby's heart rate and detect any potential signs of distress early.

Does my hospital have the resources to handle a VBAC emergency?

TOLAC should only be undertaken in a hospital facility that is capable of performing an emergency C-section immediately and has staff readily available to provide emergency care. Your healthcare provider will confirm that the facility meets these requirements.

How long should I wait between my C-section and getting pregnant again?

A short inter-delivery interval (less than 18-24 months) is associated with a higher risk of uterine rupture. It's generally recommended to wait at least 18-24 months between deliveries to allow your uterus to heal fully.

Can I have a VBAC if I am expecting a large baby or twins?

TOLAC can be considered if you are expecting twins. If your baby is estimated to be very large (macrosomia), TOLAC can still be considered, but success rates may be lower and risks might be slightly higher. Your doctor will discuss these factors with you.

What happens if my trial of labor is not successful?

If your trial of labor is not successful, or if complications arise, you will have an unplanned repeat C-section. While this carries higher risks than a successful VBAC or a planned repeat C-section, your medical team is prepared to manage this situation safely.

How does my age or BMI affect my chances of a successful VBAC?

Increased maternal age and a higher Body Mass Index (BMI, especially over 30 or 40) are factors that can slightly lower your chances of a successful VBAC. Your doctor will consider these as part of your overall risk assessment.

What are the long-term risks of having multiple C-sections?

With each additional C-section, the risks in future pregnancies increase. These include a higher chance of placenta previa (placenta covering the cervix) and placenta accreta spectrum (where the placenta grows too deeply into the uterine wall), which can lead to severe bleeding and may require a hysterectomy. There's also an increased risk of surgical adhesions.