What Is the Greatest Concern in a Vaginal Birth After Cesarean Delivery (VBAC)?

If you have previously had a cesarean delivery, you have two options for the delivery of your next child:

1. Scheduling another cesarean delivery
2. Attempting a vaginal birth after cesarean delivery (VBAC)

If you are strongly considering having VBAC, weigh the benefits and risks, as well as whether you are a candidate for this type of birth. Many women find that the benefits of VBAC outweigh the risks, and a doctor can assess you to ensure that you meet the criteria for having the best chance of successful VBAC.

VBAC attempt is also known as a trial of labor after a Cesarean (TOLAC). According to data, 60 to 80 percent of all labor after Cesarean and VBAC are successful.

Benefits of VBAC

• When VBAC is successful, no abdominal surgery is required. This reduces the risks associated with Cesarean deliveries. Vaginal delivery (including VBAC) involves less blood loss than surgery.
• Recovery time after vaginal delivery is usually shorter and requires lesser bed rest than after cesarean delivery. You'll still need to heal, but you won't have to worry about an abdominal incision.
• There are fewer restrictions on walking and lifting things.
• Individualized birth plans are possible with a vaginal delivery as opposed to cesarean delivery.
• VBAC is a good option if you intend to have a larger family and want to reduce your chances of needing another cesarean delivery.

Risks of VBAC

• Risks of VBAC are generally lower than those of a cesarean delivery but only if VBAC is successful.
• If your doctor is monitoring your delivery and believes there is a risk to you or the baby, you may require a cesarean delivery, and risks of cesarean delivery are a concern.
• When VBAC is attempted but fails, more serious complications arise.
• Complications of failed TOLAC include uterine rupture that necessitates an emergency cesarean delivery and, if severe, a hysterectomy.

To determine whether you are a good candidate for VBAC, your doctor will discuss your medical history with you, with a focus on the specifics of your previous cesarean delivery/deliveries.

You might be a good candidate for VBAC if:

• You are only pregnant with one child, have had one or two Cesarean deliveries with low transverse incisions, and have no issues that would preclude or complicate VBAC.
• You are expecting one child and have had one cesarean delivery with an unknown type of incision that is not suspected to be a high vertical (classical) uterine incision, and you have no problems that would prevent or complicate VBAC.
• You are expecting twins, have had one cesarean delivery with a low transverse uterine incision, and meet the other requirements for vaginal twin delivery.

Your doctor will probably rule out VBAC if you’ve had:

• A previous cesarean delivery with a high vertical (traditional) uterine incision.
• A previous uterine incision of unknown type (thought to be a high vertical incision).
• Certain uterine surgeries such as fibroid removal.
• Uterine rupture in the past.

Other factors that may reduce your chance of having a successful VBAC include:

• Advanced maternal age
• Poor muscle tone
• A pregnancy that continues past 40 weeks
• Labor induction
• Stalled labor
• Previous delivery in the last 18 months
• A history of at least two Cesarean deliveries and no vaginal deliveries
• Pregnancy weight gain that is excessive
• Obesity in mothers (mother has a body mass index of 40 or higher)
• A pregnancy that lasts longer than 40 weeks

The benefits and risks of an elective repeat cesarean delivery usually depend on the person’s gynecology and obstetric history.

Benefits

• An elective repeat cesarean delivery avoids the risks of vaginal birth after cesarean delivery (VBAC) and reduces the likelihood of an emergency cesarean delivery.
• There is a 1 in 1,000 chance of stillbirths occurring between 39 weeks of pregnancy and the time of delivery with VBAC. This risk is avoided because your cesarean delivery will usually be performed at 39 weeks with an elective repeat cesarean delivery.
• Some women want an elective repeat cesarean delivery because they had difficult labor in the past or because they want to plan their birth.

Risks

• If you have a cesarean delivery, you may require a longer hospital stay.
• Walking, lifting, driving, and other physical activities may be difficult for a longer period after an elective repeat cesarean delivery. Following an elective repeat cesarean delivery, there is usually a longer recovery period.
• An elective repeat cesarean delivery is a major abdominal operation with significant risks.

You should be aware of risks to yourself, risks to your baby, and implications for future pregnancies.

Risks to the mother

• There is damage to the organs close to the uterus, particularly the bladder and bowel. This is uncommon, but it becomes more common as the number of past Cesarean deliveries you have had increases.
• Infections such as endometritis, urinary tract infection, and wound infection affect approximately 8 out of every 100 women who have had a cesarean delivery.
• There is a higher risk of maternal deaths (13 in 100,000 for an elective repeat cesarean delivery compared with 4 in 100,000 for VBAC).

Risks to your baby

• Following a cesarean delivery, your baby is more likely to experience temporary breathing difficulties. This can be transient due to retained lung fluid (four to five percent following an elective repeat cesarean delivery versus two to three percent following planned VBAC) or respiratory distress syndrome (0.5 percent following an elective repeat cesarean delivery versus two to three percent following planned VBAC).
• In very few cases, the baby’s skin could be accidentally cut as the uterus is opened during the operation.

Implications for future pregnancies

• Your next child will almost certainly be delivered through a third cesarean delivery.
• The placenta may implant over the scar from a previous cesarean delivery on the uterus, resulting in a low-lying placenta. This is known as placenta previa, and it is associated with an increased risk of bleeding during pregnancy, which can lead to premature birth and an increased risk of heavy bleeding during cesarean delivery.
• In future pregnancies, there is an increased risk of placenta accreta (a life-threatening condition in which the placenta becomes firmly attached to the womb).
• With each cesarean delivery, the risk increases. There is often significant bleeding and an increased likelihood of needing a hysterectomy (surgical removal of the uterus) after delivery.

According to research, both attempted VBAC and elective repeat cesarean delivery have low absolute rates of adverse maternal and neonatal outcomes.

In general, both are reasonable options for women; however, attempted VBAC continues to be associated with higher relative rates of severe adverse maternal and neonatal outcomes than an elective repeat cesarean delivery.

The best mode of delivery in a subsequent pregnancy for women who have had a single previous cesarean delivery is debatable because there are risks and benefits to attempting VBAC or having an elective repeat cesarean delivery.

Planning the mode of delivery for a woman who has had a previous cesarean delivery is thus difficult for both the woman and her doctor.