[Predictive factors for vaginal birth after cesarean section].

OBJECTIVES

Determination of predictive factors of vaginal delivery in women with a history of caesarean section undergoing a trial of labor.

MATERIALS AND METHODS

Relevant studies were identified through Medline, and the Cochrane databases 1980-2012. Recommendations from the French and foreign obstetrical societies or colleges have been consulted.

RESULTS

In France in 2010, a trial of labor was attempted in 49 % with 75 % successful rate (EL2). The site of delivery does not appear to influence the rate of successful trial of labor (EL3). Two factors are strongly associated with vaginal birth after caesarean (VBAC): prior history of vaginal delivery and spontaneous labor (EL2). Many factors appear to decrease the rate of VBAC: maternal age above 40 years (EL3), body mass index greater than 30 kg/m(2) (EL3), birth weights greater than 4000 g (EL3), unfortunately, prediction of macrosomia seems to be inaccurate. Induction of labor with pharmacological (prostaglandins and oxytocin) and mechanical methods (Foley catheter) decreased rate of successful VBAC (EL2). The use of pelvimetry to accept or avoid trial of labor, increase the risk of elective caesarean section (EL2) and should therefore not be recommended (grade C). Nomograms are not accurate to predict fail trial of labor as its clinical relevance is limited and has not yet evaluated in French population (expert opinion).

CONCLUSION

After caesarean, trial of labor is associated with 75 % successful rate. Two factors are strongly associated with VBAC: a prior history of vaginal delivery and spontaneous labor.