Vaginal Birth After Cesarean (VBAC) & Trial of Labor After Cesarean (TOLAC)

VBAC refers to a vaginal delivery following a previous cesarean section. Patients attempting VBAC undergo a trial of labor (TOL) or trial of labor after cesarean (TOLAC).

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VBAC and TOLAC are related but distinct concepts in obstetrics:

VBAC (Vaginal Birth After Cesarean) refers to a successful vaginal delivery following a previous cesarean section.
TOLAC (Trial of Labor After Cesarean) is the attempt to have a vaginal birth after a previous cesarean, regardless of the outcome.
All VBACs are the result of a TOLAC, but not all TOLACs result in a VBAC.
TOLAC success rates vary, with studies reporting 60-80% of attempts resulting in successful VBAC.

The American College of Obstetricians and Gynecologists (ACOG) recommends that most women with one previous cesarean delivery with a low-transverse incision are candidates for TOLAC and should be counseled about VBAC and offered a TOLAC.

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Key Points

Safety	Generally safe, but with potential serious complications
Main Risks	Uterine rupture or dehiscence
Provider's Role	Counsel patients on risks, benefits, and success factors

Etiology and Epidemiology

The rise in cesarean delivery rates has increased the number of pregnant women with prior cesarean sections. VBAC can be planned or occur due to precipitant labor.

Cesarean Delivery Rates Over Time

Year	Cesarean Delivery Rate
1970	5%
2005	30%
2009 (peak)	32.9%
2016	31.9%

Benefits of Successful VBAC

Decreased maternal morbidity
Reduced risk of complications in future pregnancies
Avoidance of surgical recovery
Decrease in overall cesarean delivery rate

Recent recognition: Multiple cesarean sections increase the risk of significant obstetrical complications, including massive postpartum hemorrhage, placenta previa, and related placental disorders.

Patients planning large families may particularly benefit from VBAC by avoiding multiple cesarean deliveries.

Patient Evaluation Process

flowchart TD
    A[Initial Prenatal Visit] --> B[Comprehensive History]
    A --> C[Physical Exam]
    B --> D[Detailed Obstetric History]
    D --> E[Prior Pregnancies]
    D --> F[Pregnancy Outcomes]
    D --> G[Infant Details]
    C --> H[General Exam]
    C --> I[Pelvic Exam]
    I --> J[Clinical Pelvimetry]
    J --> K{Predictive of VBAC Success?}
    K -->|No| L[Not sole predictor]
    K -->|Yes| M[Consider for TOLAC]

TOLAC Candidacy Evaluation

Contraindications for TOLAC

Prior classical cesarean section