VBAC: antenatal predictors of success

Area of Science:

• Obstetrics and Gynecology
• Reproductive Medicine
• Maternal-Fetal Medicine

Background:

• Vaginal birth after Cesarean section (VBAC) is a significant clinical consideration.
• Identifying predictors of VBAC success is crucial for patient counseling and management.
• Previous Cesarean section (CS) indications and delivery history influence VBAC outcomes.

Purpose of the Study:

• To identify antenatal factors predicting successful VBAC.
• To develop a scoring system and nomogram for VBAC success prediction.
• To inform clinical decision-making regarding attempted VBAC.

Main Methods:

• Retrospective analysis of antenatal factors.
• Development of a predictive scoring system.
• Creation of a nomogram for VBAC success probability.

Main Results:

• Non-recurrent CS indications (e.g., breech, fetal distress) are associated with higher VBAC success rates than recurrent ones (e.g., cephalopelvic disproportion).
• Prior vaginal deliveries, especially after a CS, are strong positive predictors.
• Maternal obesity and diabetes mellitus negatively impact VBAC outcomes, while fetal macrosomia and twin gestations do not preclude VBAC.
• Short inter-pregnancy intervals (<24 months) do not decrease success, but longer intervals may reduce it.
• Post-dates pregnancies and low vertical uterine incisions do not appear to be contraindications.

Conclusions:

• A majority of attempted VBACs are successful.
• Antenatal factors can effectively predict VBAC success, enabling the development of predictive tools.
• There are limited absolute contraindications to attempting VBAC.