Why can't a woman have a vaginal birth after a classical cesarean (C-) section?

From the Guidelines

A woman should not have a vaginal birth after a classical cesarean section due to the significantly increased risk of uterine rupture, which can be life-threatening for both mother and baby. The risk of uterine rupture with a classical incision is substantially higher compared to other types of cesarean incisions, primarily because the vertical incision in the upper part of the uterus creates a weaker scar. According to a systematic analysis published in The Lancet Global Health 1, the overall prevalence of complete uterine rupture after cesarean section varies, but the risk is notably higher in women who have had a previous cesarean section and labor.

Key points to consider include:

• The structural weakness in the uterine wall after a classical cesarean section remains a significant concern regardless of the time elapsed since the surgery.
• Uterine rupture can lead to severe complications, including hemorrhage, hysterectomy, and even death for both the mother and the baby.
• The recommendation for a repeat cesarean delivery applies to women with a prior classical cesarean, emphasizing the importance of discussing delivery options with a healthcare provider early in pregnancy.
• Planning for a scheduled cesarean delivery, typically around 36-37 weeks of gestation, is crucial for women with a history of classical cesarean to minimize risks associated with uterine rupture.

Given the potential for severe morbidity and mortality associated with uterine rupture, the safest approach for women with a previous classical cesarean section is to undergo a planned repeat cesarean delivery. This approach prioritizes the health and safety of both the mother and the baby, aligning with the principles of minimizing morbidity, mortality, and optimizing quality of life.

From the Research

Reasons for Not Having a Vaginal Delivery After a Classical C-Section

• A classical C-section involves a vertical incision in the upper part of the uterus, which is associated with a higher risk of uterine rupture during subsequent pregnancies 2.
• Uterine rupture is a serious complication that can lead to severe maternal and fetal morbidity, and even mortality 3, 4, 5.
• Women with a previous classical uterine incision are generally advised against attempting a vaginal birth after cesarean (VBAC) due to the increased risk of uterine rupture 2.

Risks Associated with VBAC After a Classical C-Section

• The risk of uterine rupture is higher in women with a classical uterine incision compared to those with a low transverse uterine incision 2.
• Uterine rupture can occur without warning signs, and prompt intervention is necessary to minimize maternal and fetal complications 3, 4.
• Other risk factors for uterine rupture during VBAC include prior abdominal surgery, augmented labor, and induction of labor 6.

Management of Labor After a Classical C-Section

• Women with a previous classical uterine incision should be delivered once fetal lung maturity is documented, and a trial of labor should not be attempted 2.
• Close intrapartum management is warranted in women with a unknown or suspected classical uterine incision 2.
• The optimal management of labor in women with a previous low transverse uterine incision who desire a trial of labor is uncertain, and obstetric management should be individualized after counseling 2.