If you've delivered a baby by C-section and you're pregnant again, you might be able to choose between scheduling a repeat C-section or a vaginal birth after cesarean (VBAC).

For many women, attempting a trial of labor after cesarean (TOLAC) is possible. In 2013, the success rate for women in the U.S. who attempted a trial of labor after one previous cesarean was 70%.

VBAC isn't right for everyone, though. Certain factors, such as a high-risk uterine scar, can lower your likelihood of VBAC and make the option inappropriate. Some hospitals don't offer VBAC because they don't have the staff or resources to handle emergency C-sections. If you're considering VBAC, your health care provider can help you understand if you're a candidate and what's involved.

Common reasons for choosing a trial of labor after cesarean include:

• Impact on future pregnancies. If you're planning to have more children, VBAC might help you avoid the risks of multiple cesarean deliveries, such as placenta previa or placenta accreta.
• Lower risk of surgical complications. Successful VBAC is associated with lower rates of excessive bleeding, infection and blood clotting in one or more of the deep veins in the body (deep vein thrombosis). VBAC also might decrease the risk of surgical removal of the uterus (hysterectomy) and injury to abdominal organs, such as the bladder or bowel.
• Shorter recovery time. You'll have a shorter hospital stay after a VBAC than you would after a repeat C-section. Avoiding surgery will help you resume your normal activities sooner.
• Opportunity for an individualized birth plan. For some women, it's important to experience a vaginal delivery.

You might be a candidate for VBAC if you are:

• Pregnant with one baby, have a history of one or two prior low transverse C-sections, and have no problems that would prevent VBAC
• Pregnant with one baby, have a history of one prior C-section with an unknown type of uterine incision, and have no problems that would prevent VBAC — unless it's suspected that you had a prior high vertical (classical) uterine incision
• Pregnant with twins, have a history of one prior low transverse C-section, and are otherwise a candidate for a twin vaginal delivery

One of the greatest predictors of a successful VBAC is a prior vaginal delivery.

You're not a candidate for VBAC if you have any condition that would prevent vaginal delivery or you have had:

• A prior high vertical (classical) uterine incision
• An unknown type of prior uterine incision and it's suspected that it was a high vertical (classical) incision
• A prior uterine rupture, in which the cesarean scar on the uterus breaks open
• Certain types of prior uterine surgery, such as fibroid removal

Many health care providers won't offer VBAC if you've had more than two prior C-sections or you have a body mass index of 50 or higher at the time of delivery and you've never had a vaginal delivery. VBAC also generally isn't an option if you are pregnant with triplets or higher order multiples.

Factors that decrease the likelihood of VBAC include:

• Stalled labor
• Advanced maternal age
• Pregnancy that continues past 40 weeks
• Body mass index of 40 or higher
• Excessive weight gain during pregnancy
• Preeclampsia
• Previous delivery within 18 months
• History of two or more prior C-sections and no vaginal deliveries
• A need for labor induction when starting with a closed cervix

While a successful VBAC is associated with fewer complications than an elective repeat C-section, a failed trial of labor after cesarean is associated with more complications, including, rarely, a uterine rupture. If a scar on your uterus from a previous cesarean tears open during a trial of labor, an emergency C-section is needed to prevent life-threatening complications for you and your baby. Treatment might involve surgical removal of the uterus (hysterectomy). If your uterus is removed, you won't be able to get pregnant again.

If you've previously had a C-section and you're pregnant, you might begin talking about VBAC at your first prenatal visit. Discuss your concerns and expectations with your health care provider. Make sure he or she has your complete medical history, including records of your previous C-section and any other uterine procedures. Your health care provider might use your medical history to calculate the likelihood that you'll have a successful VBAC.

Also, plan to deliver your baby at a facility that's equipped to handle an emergency C-section. Continue discussing the risks and benefits of VBAC throughout pregnancy, especially if certain risk factors arise.

If you choose VBAC, when you go into labor you'll follow the same process that's used for any vaginal delivery. Your health care provider will likely recommend continuous monitoring of your baby's heart rate and be prepared to do a repeat C-section if needed.