Factors that increase the likelihood of successful VBAC include:

• Previous successful VBAC
• Previous vaginal delivery
• Favourable cervix
• Spontaneous labour
• Non-recurrent indication for previous C-section (e.g. breech presentation)
• Maternal age < 40 years

Factors that decrease the likelihood of successful VBAC include:

• Previous C-Section done for dystocia
• Need for induction of labour requiring cervical ripening
• Need for augmentation of labour
• Gestational age > 40 weeks
• Estimated birth weight > 4000 grams
• Maternal body mass index (BMI) > 30
• Hypertension

Prerequisites for a trial of labour after previous Caesarean birth (these should be documented):

• Baby is head down
• Previous operative report (may include opinion of previous surgeon)
• No contraindications to vaginal birth

Factors that may increase the risk of uterine rupture (these should be documented):

• Single layer (versus two-layer) closure of the previous uterine incision
• Large headed baby
• Short interval from previous C-Section (< 18 months)
• More than two previous C-Sections
• Previous Caesarean for failure to progress after fully dilated

Contraindications to a TOL (these should be documented):

• Any contraindications to labour
• Previous or suspected classical C-Section
• Previous inverted T uterine incision
• Previous uterine rupture
• Previous major uterine reconstruction
• Inability of the facility to perform an emergency C-Section
• Woman requests Elective Repeat C-Section rather than a TOL

Benefits of VBAC:

• Shorter hospitalization
• Shorter recovery time for the woman
• Improved maternal satisfaction
• Reduced health care costs