Patient information: Vaginal birth after cesarean delivery (VBAC)

INTRODUCTION

In the past, it was believed that a woman who delivered a baby by cesarean delivery (C-section) would require a C-section for all future deliveries. We now know this is not always the case. Today, many women who have a cesarean delivery can deliver vaginally in subsequent pregnancies. Over the past two decades, this practice has become increasingly common as healthcare provider have recognized that a vaginal delivery is a safe option after cesarean for many women.

Vaginal birth after cesarean delivery (VBAC) is also called a trial of labor after cesarean delivery (TOLAC).

BENEFITS OF VAGINAL BIRTH

The benefits of a VBAC may include the following:

• Reduced risk of thromboembolism (blood clot in the leg or lung)
• Shorter length of hospital stay in most cases
• Less likely to need a blood transfusion
• Possibly lower rate of postpartum fever, wound infection, uterine infection
• Fewer neonatal breathing problems

RISKS OF VAGINAL BIRTH AFTER CESAREAN

Having a vaginal birth after cesarean delivery is not without risk. During a cesarean delivery, the uterus is surgically opened. Although the surgical incision heals, there is an increased risk of uterine rupture (tearing open of the uterine wall) during future deliveries.

In general, women who undergo VBAC have a low risk of uterine rupture. However, the risk of uterine rupture is higher with VBAC than with repeat cesarean delivery. (See "Patient information: Cesarean delivery".)

The risk of uterine rupture depends in part upon the type of incision (cut) made during the first cesarean delivery. Transverse (horizontal) incisions in the lower part of the uterus are commonly used and have the lowest risk of rupture (0.2 to 1.5 percent risk). The risk is higher with other types, such as T-shaped or vertical incisions (4 to 9 percent risk) [1]. It is important to realize that the direction of the skin incision does not indicate the type of uterine incision; a woman may have a vertical skin incision and a horizontal uterine incision.

The rate of fetal death is very low with both types of delivery. However, because the risk of fetal death increases with uterine rupture, fetal death occurs more frequently with VBAC than with repeat cesarean delivery. Maternal death is very rare with either type of delivery.

CONSIDERING VBAC

The American College of Obstetricians and Gynecologists states that VBAC is an acceptable option for women who [2]:

• Do not have other conditions (as an example, placenta previa) that require cesarean delivery
• Have only one low transverse uterine incision from a past cesarean delivery
• Have no other uterine scars and has never experienced a uterine rupture
• Do not have pelvic problems or abnormalities that prevent vaginal delivery
• Have a baby in the proper position (head down)

In addition, VBAC should only be considered if a physician capable of performing a cesarean delivery, nursing staff, anesthesia, and an operating room are immediately available, in case an emergent cesarean delivery is necessary.

Women considering VBAC should discuss the risks and benefits of VBAC versus C-section, including what can happen if a cesarean delivery is needed emergently.

Management during labor — In many ways, a woman who attempts VBAC is managed similarly to other women anticipating a vaginal delivery. A fetal monitor may be used to observe the baby's heart rate and monitor for early signs of fetal distress. Medications to induce labor or improve contractions (eg, pitocin) will be used cautiously since they can increase the risk of uterine rupture. If problems occur during labor, a cesarean delivery may be recommended.

VBAC SUCCESS RATES

In general, 60 to 80 percent of women who attempt VBAC have a successful vaginal birth [3]. The chances are increased if the woman:

• Has had a vaginal delivery or VBAC in the past
• Experiences spontaneous onset of labor (labor is not induced)
• Has a normally progressing labor, including dilation and effacement (thinning) of the cervix
• Had a prior cesarean delivery due to the baby's position (breech).
• Had only one cesarean delivery
• Had the prior cesarean delivery early in labor, not after full cervical dilatation

WHERE TO GET MORE INFORMATION

Your healthcare provider is the best source of information for questions and concerns related to your medical problem. Because no two people are exactly alike and recommendations can vary from one person to another, it is important to seek guidance from a provider who is familiar with your individual situation.

This discussion will be updated as needed every four months on our web site (www.uptodate.com/patients). Additional topics as well as selected discussions written for healthcare professionals are also available for those who would like more detailed information.

Some of the most pertinent include:

Patient Level Information:
Patient information: Cesarean delivery

Professional Level Information:
Anesthesia for cesarean delivery
Cesarean delivery: Technique
Delivery of twin gestations
Induction of labor in women with prior cesarean delivery
Postterm pregnancy
Trial of labor after cesarean delivery

A number of web sites have information about medical problems and treatments, although it can be difficult to know which sites are reputable. Information provided by the National Institutes of Health, national medical societies and some other well-established organizations are often reliable sources of information, although the frequency with which they are updated is variable.

• National Library of Medicine

      (www.nlm.nih.gov/medlineplus/healthtopics.html)

• The Mayo Clinic

      (www.mayoclinic.com)

• American College of Nurse-Midwives

      (www.midwife.org, search for "VBAC")

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