Vaginal Birth After Cesarean (VBAC)
What is a vaginal birth after cesarean (VBAC)?
If you have had a cesarean delivery (also called a C-section) before, you may be able to deliver your next baby vaginally. This is called vaginal birth after cesarean, or VBAC.
If you and your doctor agree to try a VBAC, you will have what is called a "trial of labor." This means that you plan to go into labor with the goal to deliver vaginally. But as in any labor, it is hard to know if a VBAC will work. You still may need a C-section. As many as 4 out of 10 women who have a trial of labor need to have a C-section.1
Is a VBAC trial of labor safe to try?
If you have had only one cesarean delivery, VBAC may be a safe option for you. You and your doctor may think about a VBAC trial of labor if:
- You have only one low, side-to-side scar from a C-section.
- You have had 2 cesareans before, but you have also had a vaginal delivery.
- The hospital has the staff and tools to do a quick C-section in case you need one.
- You don't have a reason for a cesarean in this pregnancy, such as a placenta previa.
VBAC is considered safe if you are older than 35, you have a large fetus, or your pregnancy goes beyond 40 weeks. But these things do lower your chance of being able to deliver vaginally.
VBAC is not considered safe if you have:
- Two C-section scars and have not delivered vaginally before.
- Any scarring above the lower, thinner part of your uterus.
What are the benefits of a 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 VBAC?
The most serious risk of a VBAC is that a C-section scar could come open during labor. 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 cesarean scar and your labor is not started with medicine. This risk is why VBAC is only offered by hospitals that can do a rapid emergency C-section.
If you have a trial of labor and need to have a C-section, your risk of infection is slightly higher than if you just had a C-section.
Frequently Asked Questions
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Is VBAC Right for You?
If your current pregnancy and health history are considered low-risk, you are a good candidate for a successful vaginal birth after cesarean (VBAC). But you may have one or more conditions that lower your chances of a successful trial of labor and increase your risk of complications. As you and your doctor decide whether VBAC is right for you, think about the following information.
- Your baby is normal in size and in the head-down (vertex) position.
- Labor has started on its own (spontaneously) and your cervix is dilating well.
- No medical reason exists for a cesarean delivery with this pregnancy. (Possible medical reasons for having a cesarean include placenta previa, breech position, narrow pelvis, triplets or more, and active genital herpes.)
- You want to have a trial of labor and a vaginal delivery.
- You can deliver in a hospital that offers VBAC and has the ability to do a rapid emergency C-section.
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.
You and your doctor may consider a VBAC if: 1
- You have had two cesarean births using low transverse incisions AND a vaginal delivery. (The risk of uterine rupture increases with each additional scar. But a history of at least one vaginal birth greatly lowers this risk in women with two cesarean scars.)
- The type of incision used for your prior cesarean is unknown (previous surgery records are not available), but your doctor can judge that it is a low transverse scar based on why you had a cesarean section.
- You are carrying twins and they are positioned properly inside your uterus.
- You have delivered vaginally and by cesarean before and are now carrying a very large fetus with an estimated weight of 9 lb (4.08 kg) to 10 lb (4.54 kg). The larger the fetus, the less chance there is of delivering vaginally.
- Labor has not started on its own, but your cervix is soft and partially dilated. If you have a medical need to deliver right away, your doctor may carefully use oxytocin (Pitocin) to start labor. Your doctor may also place a thin tube with a small balloon into the cervix. This can soften the cervix without raising the chance of uterine rupture.
VBAC is not considered safe if you have: 1
- No access to a hospital that can offer close monitoring and is equipped to handle an emergency cesarean delivery.
You are not a good candidate for VBAC if you have factors that increase the risk of uterine rupture, including:1
- Labor that has not started on its own and a cervix that is closed and firm. This is especially true if you have never had a vaginal delivery. In this case, starting labor with medicine, such as misoprostol (Cytotec), raises the risk of uterine rupture during VBAC. (If oxytocin is used carefully to help a slow labor, it is less likely to increase your uterine rupture risk.)1, 2 Some doctors place a thin tube with a small balloon into the cervix. This can soften the cervix without raising the chance of uterine rupture.
- A vertical (classical) uterine incision that reaches above the lower uterus.
- Two or more cesarean scars and no previous vaginal delivery.1
- A cesarean section within the past 2 years.3
- A single-layer closure (rather than a double-layer closure) of your previous cesarean section.4
- Previous uterine surgery, such as removal of a uterine growth (fibroid) that has cut deeply into the uterus.
- A narrow (contracted) pelvis, as determined during your last delivery.
- A breech fetus, positioned with the feet or buttocks down in the uterus.
- Triplets or more during this pregnancy.
- A medical reason for a cesarean, such as active genital herpes or placenta previa, in this pregnancy.
What Affects VBAC Success
Pregnancy, labor, and delivery are different for every woman and difficult to predict. Even if your first pregnancy required a cesarean, the next one may not. The likelihood of a successful vaginal birth after cesarean (VBAC) is influenced by various factors. Usually a combination of factors affects how well or poorly a trial of labor goes.
If you are or may be a good candidate for a trial of labor, your chances of delivering vaginally are best when:1
- Your previous cesarean was not done for stalled labor.
- You do not have the same condition that led to a previous cesarean (such as a breech, or feet-down, fetus).
- You have had a vaginal delivery or a successful VBAC before.
- Your labor starts on its own, and your cervixdilates well.
- You are younger than 35.5
If you are or may be a good candidate for a trial of labor, your chances of delivering vaginally are lower when:1
- Your previous cesarean was because of difficult labor, which is called dystocia. This is especially true if you were fully dilated when you had a cesarean section for dystocia.
- You are obese.
- You are older than 35.5
- Your fetus is very large [estimated as bigger than 9 lb (4082 g)].
- You are beyond 40 weeks of pregnancy.
Risks of VBAC and Cesarean Deliveries
Whether you deliver vaginally or by cesarean section, you are unlikely to have serious complications. Overall, a routine vaginal delivery is less risky than a routine cesarean, which is a major surgery. But pregnant women who have a cesarean scar on the uterus have a slight risk of the scar breaking open during labor. 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 cesarean (VBAC).
Risks of VBAC
The risks of VBAC include:
- An unsuccessful trial of labor that ends with a cesarean delivery (most common complication). Up to 40% of women who attempt VBAC develop a problem that requires a cesarean delivery.1 Stalled labor (called dystocia) or fetal distress are common examples of problems that require a cesarean. A cesarean after a trial of labor increases the risk of infection for both the mother and baby.1
- A slight separation of an existing cesarean scar (called dehiscence). This usually causes no problems and in some cases is not even detected. The separation usually heals on its own.
- A slight risk of uterine rupture, which can be life-threatening for the mother and the baby. A uterine rupture is very rare yet very serious. If the rupture cannot be repaired quickly, removal of the uterus (hysterectomy) may be necessary to prevent severe blood loss.
The possibility of uterine rupture is influenced by the:
- Type of incision used for the previous cesarean. Scarring above the thinner, lower uterus is more likely to rupture. A low, side-to-side (transverse) incision is least likely to rupture. About 5 out of 1,000 women (0.5%) with one low, transverse incision scar have a uterine rupture during labor when the labor starts on its own without medicine.2 It is likely that these women have other risk factors that raise their chances of having this complication.
- Number of surgical uterine scars a woman has, especially if the cervix is not softened and opening (dilating). The risk of rupture increases with each additional cesarean scar.
- Use of medicine to start (induce) labor. Among women who are otherwise good candidates for VBAC, the greatest risk factor for rupture is the use of misoprostol (Cytotec) to start (induce) or strengthen labor.2, 1 Aiding a slow labor (augmentation) with careful use of oxytocin (Pitocin) has rarely been linked to uterine rupture.6
Risks of any cesarean
The risks of any cesarean delivery include:
- Infection, which may develop in the incision.
- Blood clots (a risk with any surgery). This is rare but can be dangerous.
- Fetal injury during the delivery. The injury usually is not serious.
- Breathing problems (respiratory distress syndrome) for the baby after birth if the due date has been miscalculated and a cesarean is done before the fetus's lungs are fully developed.
To lower your risk of serious complications, arrange to deliver in a hospital that has the staff and facilities to handle an emergency cesarean delivery. A doctor must be immediately available to perform an emergency cesarean if one is needed.
Future risks. With each surgery on the uterus, more scar tissue forms. If you are planning on a pregnancy after this one, scarring is an important thing to think about. After you have two scars, each additional scar in the uterus raises the risk of placenta problems in a later pregnancy, such as placenta previa or placenta accreta. These problems raise not only the risks for a fetus but also your risk of needing a hysterectomy to stop bleeding.7
For more information about cesarean risks, see the topic Cesarean Section.
Exams 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 vaginal birth after cesarean (VBAC) is a safe option may include:
- A review of surgery records to verify the type of incision used for a previous cesarean.
- A fetal ultrasound.
- Fetal heart monitoring, which is also used during labor 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 cesarean (VBAC).
Childbirth and VBAC education
To prepare for labor, consider taking a childbirth education class at your local hospital or clinic. You and your birthing partner can learn:
- What to expect during VBAC labor 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.
Other than requiring closer monitoring, labor for a VBAC is the same as normal labor. During early labor, a woman can remain as active and mobile as she wants. There are no specific restrictions for VBAC until active labor begins. During the active period of labor, continuous fetal heart monitoring is done to watch for early signs of fetal distress or uterine rupture. (For more information, see the Exams and Tests section of this topic.)
- If you are attempting VBAC and you have not had a previous vaginal birth or your previous cesarean was done early on in labor, your labor will be like a first-time labor. For example, it could take a long time.
- If you have previously had a longer trial of labor or have delivered vaginally, your body is likely to have adapted to the process, making labor easier.
For more information about labor and delivery, see the topic Labor, Delivery, and Postpartum Period.
Medicines for starting or strengthening VBAC labor
Some doctors avoid the use of any medicine to start (induce) a VBAC trial of labor. Other doctors are comfortable with the careful use of oxytocin (Pitocin) to start labor when the cervix is soft and opening (dilating). VBAC studies have shown that inducing or strengthening labor with misoprostol (Cytotec) increases the risk of uterine rupture.2
If your labor slows or stops progressing, your doctor may use oxytocin to strengthen (augment) contractions. The sparing use of oxytocin (Pitocin) is an accepted and common practice for a stalled VBAC trial of labor and is rarely linked to uterine rupture.6
As with most vaginal births, most women who choose VBAC can safely use pain medicine during labor.
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:
- Local anesthesia, which numbs the small area where the medicine is injected.
- Regional (epidural) anesthesia, which partially or fully numbs the entire lower part of the body.
- Sedatives, which help you relax and sleep but do not relieve pain.
- Opioids (narcotics), which help you relax and partially relieve pain.
Vaginal birth after cesarean (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 cesarean 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 cesarean 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.
What to Think About
If there is no medical reason for a cesarean, vaginal delivery is generally a safe option for both mother and baby. It is common, though, to fear going through labor after having had a cesarean delivery. This is especially true for women who have tried a vaginal birth but, after a long and difficult labor, ended up delivering by cesarean.
Benefits of a successful VBAC include:
- Avoiding another incision in the uterus. If you are planning on a pregnancy after this one, scarring is an important thing to think about. After you have two scars, each additional scar in the uterus raises the risk of placenta problems in a later pregnancy, such as placenta previa or placenta accreta. These problems raise not only the risks for a fetus but also your risk of needing a hysterectomy to stop bleeding.7
- Less blood loss.
- A lower risk of infection after childbirth (though for women who are obese, infection risk is higher after a VBAC than after a cesarean8).
- A lower risk of blood clots (deep vein thrombosis).
- Greater participation in the birth.
- A quicker recovery.
- Lower costs.
The ultimate decision to try a vaginal birth is made by you and your doctor. If you want to try a VBAC but your doctor is not in favor of your choice and does not have a clear reason, consider getting a second opinion.
If you are considering VBAC, talk with your doctor about:
- The risks of vaginal and cesarean deliveries in
your particular case. Here are some points to keep in mind:
- Serious complications with either vaginal or cesarean births are uncommon.
- A cesarean section is a surgical procedure and requires the use of anesthesia. Any surgery carries a risk of infection, excessive blood loss, and problems caused by the anesthesia.
- Women who need a cesarean after a VBAC trial of labor have a higher rate of infection than those who have a cesarean without a VBAC trial of labor.1
- Whether your doctor will be available in the hospital throughout your labor and whether the hospital has facilities for an emergency cesarean delivery.
- The possibility that a trial of labor may end in cesarean delivery.
- How and at what point during labor the decision is made to do a repeat cesarean.
- Which types of pain medicine or anesthesia you may use during labor and delivery or during a cesarean.
- Your specific risk factors for uterine rupture during VBAC and the possible complications of a rupture, such as removal of the uterus (hysterectomy).
- American College of Obstetricians and Gynecologists (2004, reaffirmed 2007). Vaginal birth after previous cesarean delivery. ACOG Practice Bulletin No. 54. Obstetrics and Gynecology, 104(1): 203–212.
- Lydon-Rochelle M, et al. (2001). Risk of uterine rupture during labor among women with a prior cesarean delivery. New England Journal of Medicine, 345(1): 3–8.
- Bujold E, et al. (2002). Interdelivery interval and uterine rupture. American Journal of Obstetrics and Gynecology, 187(5): 1199–1202.
- Bujold E, et al. (2002). The impact of single-layer or double-layer closure on uterine rupture. American Journal of Obstetrics and Gynecology, 186(6): 1326–1330.
- Bujold E, et al. (2004). Trial of labor in patients with a previous cesarean section: Does maternal age influence the outcome? American Journal of Obstetrics and Gynecology, 190(4): 1113–1118.
- Cunningham FG, et al. (2005). Prior cesarean delivery. Williams Obstetrics, 22nd ed., pp. 607–617. New York: McGraw-Hill.
- Paré E, et al. (2005). Vaginal birth after caesarean section versus elective repeat caesarean section: Assessment of maternal downstream health outcomes. British Journal of Obstetrics and Gynaecology, 113(1): 75–85.
- Edwards RK, et al. (2003). Deciding on route of delivery for obese women with a prior cesarean delivery. American Journal of Obstetrics and Gynecology, 189(2):385–390.
Other Works Consulted
- Institute for Clinical Systems Improvement (2005, revised 2007). Health care guideline: Management of labor. Available online: http://www.icsi.org/guidelines_and_more/gl_os_prot/womens_health/labor/labor__management_of__2.html.
- Melnikow J, et al. (2001). Vaginal birth after cesarean in California. Obstetrics and Gynecology, 98(3): 421–426.
|Author||Sandy Jocoy, RN|
|Editor||Kathleen M. Ariss, MS|
|Associate Editor||Pat Truman, MATC|
|Primary Medical Reviewer||Sarah Marshall, MD - Family Medicine|
|Specialist Medical Reviewer||Kirtly Jones, MD - Obstetrics and Gynecology|
|Last Updated||April 17, 2009|
Last Updated: April 17, 2009