Trial of labour after caesarean section: Two-year analysis at a Portuguese centre

Abstract

We conducted a retrospective study aimed at determining variables associated with a higher success rate for vaginal delivery after caesarean section, and assessing the impact of induction of labour. Secondarily, we aimed to describe our vaginal delivery and uterine rupture rates with the use of a controlled-release dinoprostone vaginal insert for cervical ripening. Of 292 women who met the inclusion criteria, induction of labour occurred in 48% (94% with dinoprostone). There was a non-significant difference between the vaginal delivery rate of spontaneous labour (57%) and induction of labour (33%), after adjusting for confounding variables. The success rate was influenced by a Bishop score ≥6, previous vaginal delivery and previous caesarean for dystocia or failed induction. There was only one case of uterine rupture, which was associated with dinoprostone use (overall rate 0.34%, 0.77% for dinoprostone). Impact statement Trial of labour after caesarean section is considered an alternative to elective repeat caesarean. Both present associated benefits and risks, the most fearsome of which is uterine rupture during labour (0.78% in term pregnancies). Induction is also possible but carries a higher risk of uterine rupture and lower success rate for vaginal birth. Prostaglandins have been of particular concern due to a higher risk of uterine scar rupture, estimated at 2% for dinoprostone; however, its use as a controlled-release vaginal insert has been under-reported. Our study confirms the reported impact of previous vaginal delivery, previous caesarean indication and Bishop score at admission on success rate for vaginal birth after caesarean. We were unable to prove a lower success rate for induction of labour after adjusting for other variables. Despite our study limitations, we report on the use of a controlled-release vaginal insert with 10mg of dinoprostone in 130 women with a uterine rupture rate of 0.77%, lower than previously reported and similar to the overall rate estimated for term pregnancies. This dinoprostone formulation may be safer than previously reported but larger studies, and preferably randomised controlled trials, are needed to confirm these findings.