Comparison of Caesarean sections and instrumental deliveries at full cervical dilatation: a retrospective review.

INTRODUCTION: This study aimed to compare instrumental vaginal deliveries (IDs) and Caesarean sections (CSs) performed at full cervical dilatation, including factors influencing delivery and differences in maternal and neonatal outcomes.

METHODS: A retrospective review was conducted of patients who experienced a prolonged second stage of labour at Singapore General Hospital from 2010 to 2012. A comparison between CS and ID was made through analysis of maternal/neonatal characteristics and peripartum outcomes.

RESULTS: Of 253 patients who required intervention for a prolonged second stage of labour, 71 (28.1%) underwent CS and 182 (71.9%) underwent ID. 5 (2.0%) of the patients who underwent CS had failed ID. Of the maternal characteristics considered, ethnicity was significantly different. Induction of labour and intrapartum epidural did not influence delivery type. 70.4% of CSs occurred outside office hours, compared with 52.7% of IDs (p = 0.011). CS patients experienced a longer second stage of labour (p < 0.001). Babies born via CS were heavier (p < 0.001), while the ID group had a higher proportion of occipitoanterior presentations (p < 0.001). Estimated maternal blood loss was higher with CSs (p < 0.001), but neonatal outcomes were similar.

CONCLUSION: More than one in four parturients requiring intervention for a prolonged second stage of labour underwent emergency CS. Low failed instrumentation rates and larger babies in the CS group suggest accurate diagnoses of cephalopelvic disproportion. The higher incidence of CS after hours suggests trainee reluctance to attempt ID. There were no clinically significant differences in maternal and neonatal morbidity.