What is a vaginal birth after cesarean delivery (VBAC)?

If you had a cesarean section delivery with your previous baby and are thinking about a vaginal delivery with this baby, then please discuss this subject with your health care provider. A VBAC stands for a vaginal delivery after a cesarean birth. Your health care provider will discuss whether a VBAC is recommended or not for the delivery of your baby.

What is a trial of labor?

A trial of labor is when you are allowed to go into natural labor and start the process of vaginal delivery while being carefully monitored.

If your doctor says you can have a trial of labor, you should go to the hospital when your labor begins or when your bag of waters breaks. Your labor is monitored. Your health care providers will test your blood type and group. You will have an IV or saline lock so you can quickly be given IV fluids or medication if needed. You will be allowed to continue your labor and a vaginal birth if there is no evidence of problems for you or your baby.

Your contractions may be stimulated with small doses of oxytocin or prostaglandin gel. If there are signs of abnormal bleeding, abnormal fetal heart rate patterns, or failure to make adequate progress in labor, you will have a repeat cesarean birth.

When can a VBAC be done?

Your doctor will consider certain facts about your last delivery or deliveries to decide whether you should have a trial of labor for vaginal birth. The main concern relates to the scar left in your uterus by the previous cesarean birth. You do not want it to come apart during labor or vaginal birth. Your doctor will encourage and allow you to have a trial of labor if:

• You had one or two low-segment transverse uterine incisions with previous cesarean deliveries. That is, an incision that was cut horizontally (crosswise) rather than vertically. Your doctor will look at your medical records to see which type of incision you had.
• You have a doctor immediately available in case there are any problems or an emergency C-section needs to be done.
• You have already had a successful vaginal delivery after a previous cesarean delivery.
• Your pelvis is large enough for a vaginal birth.
• You have no other uterine scars or previous ruptures of the uterus.

VBAC is not recommended for all women. Your doctor will not allow a trial of labor if:

• An immediate emergency cesarean delivery can't be performed, if needed, because a surgeon, anesthesia, or sufficient staff are not available at the hospital.
• For a previous cesarean delivery, you had a vertical or T-shaped cut in the uterus.
• You have a complication in your pregnancy that suggests that labor would not be safe for you or the baby.
• You are expecting more than one baby (for example, twins).
• Your baby is in the breech position (the baby's bottom or feet are down first instead of the head).
• You have a pelvis that is too small for a vaginal birth.
• You or the baby have medical problems that would make a C-section safer.

If it is expected that your baby will weigh over 8.8 pounds (4000 grams), this does not necessarily mean that you cannot have a trial of labor. But, your health care provider will need to watch your labor and delivery very closely.

What are the benefits?

These are the reasons it is good to try to have a VBAC:

• Less risk. Vaginal deliveries have fewer risks for you and the baby than cesarean delivery. Vaginal deliveries require fewer blood transfusions and result in fewer infections.
• Shorter recovery time. Your hospital stay is shorter and your recovery at home is faster with a lot less discomfort.
• More involvement. You and your family can be more involved with the birth. Excellent pain relief, such as an epidural, which numbs the lower half of the body, may be used during a vaginal birth.
• Usually less cost.

What are the risks associated with a VBAC?

The biggest risk for both you and the baby is that the scar from the previous cesarean delivery will tear and rupture the uterus during labor. However, the risk of uterine rupture is low. The risk is about 1.5% or less in women who have had one previous cesarean birth. If any signs of rupture do occur during labor, an emergency cesarean delivery will be done. An emergency cesarean delivery does carry more risk of infection and other problems than a scheduled cesarean delivery.

What should I discuss with my health care provider?

If you have had a cesarean delivery, talk to your health care provider about the possibility of a vaginal delivery for your next baby. Be sure to discuss the risks and whether or not you are a good candidate for a VBAC. Find out whether the hospital where you plan to deliver is prepared for an emergency cesarean delivery and emergency infant care if necessary.

Reviewed and edited by UMHS Smart Moms, Healthy Babies Team, May 2005