It used to be 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 it has become recognized that a vaginal delivery after a c-section is a safe option for many women.
Vaginal birth after cesarean delivery (VBAC) is also called a trial of labour after cesarean delivery (TOLAC).
Benefits of vaginal birth
The benefits of a VBAC may include:
- reduced risk of thromboembolism (blood clot in the leg or lung),
- shorter length of hospital stay in most cases,
- fewer blood transfusions,
- possibly lower rate of postpartum fever, wound infection, uterine infection, and;
- fewer neonatal breathing problems.
Risks of vaginal birth after cesarean
There are some risks to having a vaginal birth after cesarean delivery:
- Increased risk of uterine rupture (tearing of the uterine wall). During a cesarean delivery, the
uterus is surgically opened. Although the incision (opening) heals, there is an increased risk of
uterine rupture during future deliveries. Generally, women who undergo VBAC have a low risk
of uterine rupture but the risk is higher with VBAC than with another c-section.
- The risk of uterine rupture depends in part on the type of incision (cut) made during the first cesarean delivery. Transverse (side to side) 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) or approximately 1 in 200 deliveries. The risk is higher with other types, such as T-shaped or vertical incisions (up and down) (4 to 9 percent risk). The direction of the incision you see on your skin incision will not indicate the type of uterine incision you’ve had; a woman may have a vertical skin incision and a horizontal uterine incision. o
- The rate of fetal death and/or brain injury in all types of deliveries is very low but they increase with uterine rupture.
- Maternal death is very rare with either type of delivery.
VBAC is an acceptable option for women who:
- do not have other conditions (eg. placenta previa) that require cesarean delivery;
- have only one low transverse uterine incision from a past cesarean delivery;
- have no other uterine scars and have never experienced a uterine rupture;
- do not have pelvic problems or abnormalities that prevent vaginal delivery, and;
- have a baby in the proper position (head down).
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.
If you are considering VBAC, please discuss the risks and benefits of VBAC versus c-section with your care provider, including what can happen if a cesarean delivery is needed emergently.
Management during labour
In many ways, a woman who attempts VBAC is managed similarly to other women anticipating a vaginal delivery. A fetal monitor will be used to observe the baby’s heart rate and monitor for early signs of fetal distress. Medications to induce labour or improve contractions (e.g. oxytocin) may be used cautiously if necessary since they can increase the risk of uterine rupture. If problems occur during labour, 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. The chances are increased if the woman:
- has had a vaginal delivery or VBAC in the past;
- experiences spontaneous onset of labour (labour is not induced);
- has a normally progressing labour, including dilatation and effacement (thinning) of the cervix;
- had a prior cesarean delivery due to the baby’s position (breech);
- had only one cesarean delivery; and
- had the prior cesarean delivery early in labour, 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.
The following organizations also provide reliable health information (links open in new windows):
- National Library of Medicine
- The Mayo Clinic
- American College of Nurse-Midwives (search for “VBAC)
- Society of Obstetricians and Gynecologists of Canada (search for VBAC)