The impact of analgesic intervention during the second stage of labour: a retrospective cohort study.

PURPOSE: The incidence of epidural top-ups received in the second stage of labour in nulliparous women and the obstetrical and neonatal implications associated with these boluses are explored in this retrospective observational study. We hypothesized that an epidural top-up in the second stage of labour reduces operative deliveries by resolving inadequate analgesia.

METHODS: A population-based cohort analysis was performed using perinatal data from 1 January 2013 through 31 December 2014. An anesthesia database provided information to determine the top-up incidence. Women with or without a top-up for second-stage duration were compared for method of delivery and neonatal characteristics using descriptive statistics. Logistic regression identified predictive factors for method of delivery.

RESULTS: Of the 1,462 women with a second stage of labour > one hour who received epidural analgesia, 105 (7%) required a top-up during the second stage of labour. Women who received a top-up were more likely to have had induction of labour and/or augmentation (89% vs 76%; odds ratio [OR], 2.43; 95% confidence interval [CI], 1.32 to 4.49; P = 0.003), a longer second stage (303 min vs 171 min; mean difference, 132 min; 95% CI, 113 to 151; P < 0.001), and more assisted vaginal (41% vs 17%; OR, 3.35; 95% CI, 2.21 to 5.1; P < 0.001) or Cesarean deliveries (26% vs 11%; OR, 3.04; 95% CI, 1.91 to 4.8; P < 0.001) than women without a top-up.

CONCLUSION: Most women who received a top-up had a vaginal (spontaneous or assisted) delivery. Compared with women without a top-up, women requiring a top-up had more predictors of difficult labour and higher rates of assisted vaginal delivery and Cesarean delivery.