Vaginal birth after caesarean section: a multicentre study on prognostic factors and feasibility

Vaginal birth after caesarean (VBAC) is an option to avoid major abdominal surgery and many consequences related to repeated caesarean delivery. In the last years, many efforts have been made to increase the number of patients attempting trial of labour after caesarean (TOLAC). The aim of our study was to identify the most important factors associated with the success of VBAC.

A retrospective study was conducted in two Italian referral centres. Subjects included were singleton and morphologically normal pregnancy with previous C-section. Subjects with an inter-pregnancy interval shorter than 18 months, a large for gestational age baby, a pregnancy complicated with gestational diabetes and a previous unclassified uterine scar were excluded. The characteristics of the subjects were compared and a logistic regression was performed to evaluate variables associated with successful VBAC.

Of the 300 patients included, 224 (74.7%) achieved VBAC while 76 (25.3%) underwent C-section after failed TOLAC. The number of previous C-sections was not significantly associated with the success of TOLAC. Factors positively associated with achievement of VBAC were previous vaginal delivery (OR of 6.88 for one and 9.68 for more than one) and oxytocin implementation (OR 3.32). No maternal and neonatal adverse events occurred.

Our results show that attempting VBAC is a feasible option in referral centres after adequate evaluation of the potential factors affecting the probability of success. A careful record of obstetrical history and management of labour can provide clinicians useful information to counsel women before and during labour.