Vaginal Birth After Cesarean Delivery

Vaginal Birth After Cesarean Delivery: Deciding on a Trial of Labor

It was once thought that if a woman had one cesarean delivery, all other babies she had should be born in the same way. Today, it is known that many women can undergo a trial of labor after a cesarean delivery (called TOLAC). After a successful TOLAC, many women will be able to give birth through the vagina (called a vaginal birth after cesarean delivery, or VBAC).

TOLAC is not the right choice for every woman, but it is a good choice for many women. It is important to understand the risks and benefits before deciding to attempt TOLAC and VBAC.

This pamphlet explains

  • your choices when planning your delivery
  • why you may want to think about TOLAC
  • the risks that are involved
  • whether TOLAC is right for you

Your Choices

A woman who has had a previous cesarean delivery has the following choices when planning how to give birth again:

  • She can have a scheduled cesarean delivery.
  • She can try to have a VBAC. If a woman wants to try VBAC and is considered a good candidate, she will undergo TOLAC.

Of women who undergo TOLAC, 60–80% succeed and are able to give birth vaginally. But if problems arise during TOLAC, the baby may need to be born by emergency cesarean delivery. For example, if the baby is not tolerating labor, or if labor does not progress, an emergency cesarean delivery may be needed. There are more risks, such as a greater risk of infection, with having an emergency cesarean delivery after TOLAC than having a planned cesarean delivery. The least number of risks occur with a successful VBAC.


Reasons to Consider TOLAC

There are many reasons why a woman may want to consider TOLAC. Compared with a planned cesarean delivery, a VBAC after successful TOLAC is associated with the following benefits:

  • No abdominal surgery
  • Shorter recovery period
  • Lower risk of infection
  • Less blood loss

For women planning to have more children, VBAC may help them avoid problems linked to multiple cesarean deliveries. These problems include hysterectomy, bowel or bladder injury, and certain problems with the placenta.



Both TOLAC and repeat planned cesarean delivery have risks. Both can cause infection, injury, blood loss, and other complications. With TOLAC, the risk of most concern is the possible rupture of the cesarean scar on the uterus or the uterus itself. Although a rupture of the uterus is rare, it is very serious and may harm both mother and baby. If a woman is considered at high risk of rupture of the uterus, TOLAC should not be tried.

The incision made in the uterine wall for a cesarean birth may be low transverse, low vertical, or high vertical. The type of incision made in the skin may not be the same type of incision made in the uterus.


Some types of uterine incisions are more likely to cause rupture than others. For cesarean birth, one incision is made in the abdomen and another incision is made in the uterus. There are three types of uterine incisions:

  1. Low transverse—A side-to-side cut made across the lower, thinner part of the uterus
  2. Low vertical—An up-and-down cut made in the lower, thinner part of the uterus
  3. High vertical (also called “classical”)—An up-and-down cut made in the upper part of the uterus

Low transverse incisions carry the least chance of rupture. They also are the most common type of incision used in cesarean births. The risk of uterine rupture with this type of incision is less than 1%. Women who have had one or two previous cesarean deliveries with low transverse incisions are candidates for TOLAC. Women with high vertical incisions are generally not considered to be candidates for TOLAC because their risk of a uterine rupture in labor is increased. TOLAC can be considered if a woman has had a low vertical incision.

It is not possible to tell what kind of incision was made in the uterus by looking at the scar on the skin. Medical records from the previous delivery probably include this information. If medical records are not available, a woman should understand the risks associated with all three types of incisions. It is still possible to have a VBAC unless it is highly suspected that the incision is a high vertical incision.


Other Factors

In deciding whether to have a TOLAC, several factors should be considered in addition to the type of incision. These factors include the desire for more children, whether a woman has certain complications, and the hospital where the birth will take place:

  • Future deliveries—Multiple cesarean deliveries are associated with additional potential risks. If you know that you want more children, you should think about these risks when making your decision. Even if you currently think you do not want more children, you may change your mind later.
  • Prior uterine rupture—If you had this complication in a previous pregnancy, TOLAC is not advised. Women who have had a previous uterine rupture should give birth by repeat cesarean delivery before labor starts on its own. An early delivery also may be recommended (before 39 weeks of pregnancy).
  • A pregnancy problem or a medical condition that makes vaginal delivery risky—Vaginal delivery may not be recommended if there is a problem with the placenta or problems with the baby or if you have certain medical conditions during pregnancy.
  • Type of hospital—The hospital in which a woman has a TOLAC should be prepared to deal with emergencies that may arise. Some hospitals may not offer TOLAC because hospital staff do not feel they can provide needed emergency care. You and your health care provider should consider the resources available at the hospital you have chosen and whether these resources are appropriate for TOLAC. If the hospital you have chosen does not have appropriate resources, you often can be referred to one that does.

Chances for Successful TOLAC and VBAC

Although it is not possible to predict whether TOLAC and VBAC will be successful, several factors have been shown to increase or decrease the likelihood of success:

  • Previous deliveries—Women who have had a prior vaginal delivery are more likely to have a successful TOLAC and VBAC.
  • Spontaneous labor—The success rate for VBAC is decreased if there is a need to induce labor (use drugs or other means to bring on labor). Certain drugs or combinations of drugs that induce labor are avoided in women undergoing TOLAC (eg, misoprostol). Other means of labor induction can be considered.
  • Reason for previous cesarean delivery—If the previous cesarean delivery was done for a condition that is likely to recur, such as a slowed or stopped labor, TOLAC and VBAC are less likely to be successful than if the previous cesarean delivery was done for a condition that is not likely to recur, such as a breech presentation.

Other factors that may decrease the chance of a successful TOLAC and VBAC include:

  • Increased age of the mother
  • High birth weight of the baby
  • High body mass index of the mother
  • Pregnancy beyond 40 weeks of gestation
  • Preeclampsia
  • Short time between pregnancies

Is TOLAC Right for You?

You should discuss delivery options with your health care provider early in pregnancy. This way, you and your health care provider have the most time to consider all of the options. Many of the factors that go into the decision are known early in pregnancy. Also, if the type of incision used in the previous cesarean delivery is not known, an attempt can be made to find this information.

Before deciding whether to try VBAC, you need to know the risks and benefits of both TOLAC and planned cesarean delivery. You also should discuss your individual chances of having a successful TOLAC and VBAC and the risks associated with an emergency cesarean delivery. For women considering TOLAC and VBAC, chances for success should be as high as possible (see box).


Be Prepared for Changes

Be prepared for changes to your delivery plan. If you have chosen TOLAC, things can happen during pregnancy and labor that alter the balance of risks and benefits. For example, you may need to have your labor induced, which can reduce the chances of a successful vaginal delivery and perhaps increase the chance of complications during labor. In the event that circumstances change, you and your health care provider may want to reconsider your decision.

If you have chosen a repeat cesarean delivery, in some situations, TOLAC may be advised. For example, if you have planned a cesarean delivery but go into labor before your scheduled surgery, it may be best to consider TOLAC if you are far along in your labor and your baby is healthy.




TOLAC, VBAC, and repeat cesarean birth have risks and benefits. When considering your options, you need to know the risks and weigh them against the benefits. Your health care provider can help guide you in making the best decision for you and your baby.



Body Mass Index: A measure of a person’s weight in relation to height.

Breech Presentation: A situation in which a fetus’s buttocks or feet would be born first.

Cesarean Delivery: Delivery of a baby through incisions made in the mother’s abdomen and uterus.

Gestation: Pregnancy; the period from conception until birth.

Hysterectomy: Removal of the uterus.

Placenta: Tissue that provides nourishment to and takes away waste from the fetus.

Preeclampsia: A condition of pregnancy in which there is high blood pressure and protein in the urine.

Uterus: A muscular organ located in the female pelvis that contains and nourishes the developing fetus during pregnancy.