Topic Overview

What is a vaginal birth after caesarean (VBAC)?

If you have had a caesarean delivery (also called a C-section) before, you may be able to deliver your next baby vaginally. This is called vaginal birth after caesarean, or VBAC.

Most women, whether they deliver vaginally or by C-section, don't have serious problems from childbirth.

If you and your doctor or midwife agree to try a VBAC, you will have what is called a "trial of labour after caesarean," or TOLAC. This means that you plan to go into labour with the goal to deliver vaginally. But as in any labour, it is hard to know if a VBAC will work. You still may need a C-section. About 25 out of 100 women who have a trial of labour need to have a C-section. This means about 75 out of 100 women who have a TOLAC deliver vaginally.^{footnote 1}

Is a trial of labour safe?

Having a vaginal birth after having a C-section can be a safe choice for most women. Whether it is right for you depends on several things, including why you had a C-section before and how many C-sections you've had. You and your doctor or midwife can talk about your risk for having problems during a trial of labour.

A woman who chooses VBAC is closely monitored. As with any labour, if the mother or baby shows signs of distress, an emergency caesarean section is done.

What are the benefits of a TOLAC and VBAC?

The benefits of a VBAC compared to a C-section include:

• Avoiding another scar on your uterus. This is important if you are planning on a future pregnancy. The more scars you have on your uterus, the greater the chance of problems with a later pregnancy.
• Less pain after delivery.
• Fewer days in the hospital and a shorter recovery at home.
• A lower risk of infection.
• A more active role for you and your birthing partner in the birth of your child.

What are the risks of TOLAC?

The most serious risk of a trial of labour is that a C-section scar could come open during labour. This is very rare. But when it does happen, it can be very serious for both the mother and the baby. The risk that a scar will tear open is very low during VBAC when you have just one low caesarean scar and your labour is not started with medicine. This risk is why VBAC is often only offered by hospitals that can do a rapid emergency C-section.

If you have a trial of labour and need to have a C-section, your risk of infection is slightly higher than if you just had a C-section.

Is VBAC Right for You?

Having a vaginal birth after having a C-section can be a safe choice for most women. But it can have risks for both the mother and the baby. Whether VBAC is right for you depends on what risk factors (things that increase your risk) you have that could make it unsafe. You and your doctor or midwife can decide whether VBAC is right for you.

As with a first-time childbirth, even if you are a good candidate for a successful VBAC, there is no guarantee that you will give birth vaginally and without complications.

What Affects VBAC Success

Pregnancy, labour, and delivery are different for every woman and difficult to predict. Even if your first pregnancy required a caesarean, the next one may not. The likelihood of a successful vaginal birth after caesarean (VBAC) is influenced by many things. Usually a combination of things affects how well or poorly a trial of labour goes.

Your chances of a successful VBAC are best when:^{footnote 2}

• Your previous caesarean was not done for stalled labour.
• You do not have the same condition that led to a previous caesarean (such as a breech, or feet-down, fetus).
• You have had a vaginal delivery or a successful VBAC before.
• Your labour starts on its own and your cervix dilates well.
• You are younger than 35.

Your chances of a successful VBAC are lower when:^{footnote 2}

• Your previous caesarean was because of difficult labour, which is called dystocia. This is especially true if you were fully dilated when you had a caesarean section for dystocia.
• You are obese.
• You are older than 35.
• Your fetus is estimated to be very large [bigger than 4000 g (9 lb)].
• You are beyond 40 weeks of pregnancy.
• Your last pregnancy was less than 19 months ago.
• You have pre-eclampsia.

VBAC can be considered for pregnancies with twins.

Risks of VBAC and Caesarean Deliveries

Whether you deliver vaginally or by caesarean section, you are unlikely to have serious complications. Overall, a routine vaginal delivery is less risky than a routine caesarean, which is a major surgery. But a pregnant woman who has a caesarean scar on the uterus has a slight risk of the scar breaking open during labour. This is called uterine rupture.

Although rare, uterine rupture can be life-threatening for both mother and baby. So women with risk factors for uterine rupture should not attempt a vaginal birth after caesarean (VBAC).

Risks of VBAC

The risks of VBAC include:

• Problems during labour that result in a caesarean delivery. This occurs with about 25 out of 100 women who try VBAC. But it doesn't happen with 75 out of 100 women who try VBAC.^{footnote 1}
• Rupture of the scar on the uterus, which is rare but can be deadly to the mother and baby. About 5 out of 1000 women have a uterine rupture during a trial of labour.^{footnote 1} A vertical incision used in a past C-section, use of certain medicines to start (induce) labour, and many scars on the uterus from past C-sections or other surgeries are some of the things that can increase the chance of a rupture.
• The chance of infection. Women who have a trial of labour and end up having a C-section have a higher risk of infection. This means that the risk of infection is lower after vaginal births and after planned cesareans.^{footnote 2}

Risks of any caesarean

The risks of caesarean delivery include:

• Infections.
• Pain.
• Blood loss that requires a blood transfusion.
• Genital or urinary problems.
• Blood clots.
• Risks from anesthesia.
• A longer recovery time.
• Injury to the baby during the delivery. The injury usually isn't serious.
• Breathing problems (respiratory distress syndrome) for the baby after birth if the due date has been miscalculated and a caesarean is done before the baby's lungs are fully developed.

Future risks. If you are planning to get pregnant again, it's important to think about scarring. After you have two C-section scars, each added scar in the uterus raises the risk of placenta problems in a later pregnancy. These problems include placenta previa and placenta accreta, which raise the risk of problems for the baby and your risk of needing a hysterectomy to stop bleeding.

Examinations and Tests

Besides the usual prenatal tests, your doctor will take measures to assess whether vaginal delivery is likely to be a safe birthing option for you. (For more information on standard prenatal tests, see the topic Pregnancy.) These extra measures can help you and your doctor make a well-informed decision about your delivery.

Assessments done sometime during the pregnancy to help find out whether a trial of labour is a safe option may include:

• A review of surgery records to verify the type of incision used for a previous caesarean.
• A fetal ultrasound.
• Fetal heart monitoring, which is also used during labour and delivery to watch for fetal distress. Fetal heart monitoring can also help detect a sudden uterine rupture. A rupture is typically followed by a sudden and then ongoing drop in fetal heart rate. The mother might notice bleeding and pain.

What To Expect

Information, preparation, and teamwork are needed for a successful vaginal birth after caesarean (VBAC).

Childbirth and VBAC education

To prepare for labour, consider taking a childbirth education class at your local hospital or clinic. You and your birthing partner can learn:

• What to expect during labour and delivery.
• How to manage the birth using controlled breathing and emotional and physical support.
• What medical pain control options may be available for a vaginal delivery.

Labour

Other than requiring closer monitoring, trial of labour after caesarean, or TOLAC labour, is the same as normal labour. During early labour, a woman can remain as active and mobile as she wants. There are no specific restrictions for TOLAC until active labour begins. During the active period of labour, continuous fetal heart monitoring is done to watch for early signs of fetal distress or uterine rupture. (For more information, see Examinations and Tests.)

If you are attempting a trial of labour and you have not had a previous vaginal birth or your previous caesarean was done early on in labour, your labour will be like a first-time labour.

Medicines for starting or strengthening a trial of labour

As the end of pregnancy nears, the cervix normally becomes soft and begins to open (dilate) and thin (efface), preparing for labour and delivery. When labour does not naturally start on its own, labour may be started artificially (induced).

Some doctors avoid the use of any medicine to start (induce) a trial of labour, because they are concerned about uterine rupture. Other doctors are comfortable with the careful use of oxytocin to start labour when the cervix is soft and opening (dilating).

If your labour slows or stops progressing, your doctor may use oxytocin to strengthen (augment) contractions.

Pain medicine

As with most vaginal births, most women who choose VBAC can safely use pain medicine during labour.

Pain medicine usually is started when the cervix has opened (dilated) 3 cm (1.2 in.) to 4 cm (1.6 in.). Types of pain medicines used include:

Recovery

Vaginal birth after caesarean (VBAC) recovery is similar to recovery after any vaginal birth. After a vaginal delivery, the mother and baby can usually go home within 24 to 48 hours. By comparison, recovery from a caesarean section requires 2 to 4 days in the hospital and a period of limited activity as the incision heals.

The overall risk of infection is low for both vaginal and caesarean deliveries. But it is lower after a vaginal birth. Before you leave the hospital, you will receive a list of signs of infection to watch for in the first few weeks after delivery.