Vaginal birth after one caesarean section: analysis of indicators of success

A study was carried out among 81 women with previous one caesarean section (CS) done for non-recurrent indications to confirm the efficacy and safety of trial of labour (TOL) and to examine the effect of various factors on the mode of delivery. Singleton term pregnancy, vertex presentation and adequate pelvic capacity were the pre-requisites for case selection. Careful monitoring was done during labour and effect of various factors on the outcome was analysed statistically. Success rate of TOL was 73%. A non-recurrent indication for previous CS, such as malpresentation and foetal distress is associated with higher success rate of vaginal birth after caesarean (VBAC) compared to recurrent indications, such as cephalopelvic disproportion (CPD) and failure to progress (FTP). Prior vaginal birth improves the success rate (87%) of VBAC. Factors like premature rupture of membranes, hypertensive disorders of pregnancy, and post-date pregnancy did not affect the outcome adversely. Rate of emergency CS was 44% in women with floating head foetus, 39% in induction/augmentation group and 43% when birth weight of the foetus was > 3000 g. No maternal/perinatal mortality observed. Maternal/perinatal morbidity was low in cases with successful TOL. Uterine rupture occurred in one woman. There are few absolute contra-indications to attempted VBAC. Though the success rate does vary with different pre-existing factors, the clinician may anticipate greater than 50% chance for success in any individual labour.