Cohort study of operative delivery in the second stage of labour and standard of obstetric care.

OBJECTIVE: To assess the maternal and neonatal morbidity following operative delivery in the second stage of labour in relation to the standard of obstetric care.

DESIGN: Cohort study.

SETTING: Maternity units in two teaching hospitals in Bristol, United Kingdom. Three hundred and ninety-three women with term, singleton, cephalic pregnancies who required operative delivery in theatre at full dilatation between February 1999 and February 2000.

METHODS: Morbidity was compared for completed instrumental delivery, failed instrumental delivery and immediate caesarean section in relation to duration of second stage of labour, number of pulls at attempted instrumental delivery, number of instruments used and operator experience.

MAIN OUTCOME MEASURES: Maternal trauma, admission to special care baby unit, neonatal trauma.

RESULTS: Failed instrumental delivery after a long second stage of labour was associated with increased maternal trauma (adjusted odds ratios [OR] 4.1, 95% confidence interval [CI] 1.1, 16.5). More than three pulls at attempted instrumental delivery was associated with increased neonatal trauma for completed (adjusted OR 4.2, 95% CI 1.6, 9.5) and failed deliveries (adjusted OR 7.2, 95% CI 2.1, 24.0). Babies delivered after failed instrumental delivery with more than three pulls were at increased risk of admission to special care baby unit (adjusted OR 6.2, 95% CI 1.6, 22.8) The use of multiple instruments was associated with increased neonatal trauma (adjusted OR 3.1, 95% CI 1.5, 6.8; adjusted OR 4.4, 95% CI 1.3, 14.4, for completed and failed deliveries, respectively). Excessive pulls and multiple instrument use were associated with an initial attempt at vaginal delivery by an inexperienced operator, 25/48 (52%) and 34/75 (45%).

CONCLUSIONS: Guidelines for safe operative delivery in the second stage of labour should be developed and adhered to in order to reduce morbidity, particularly neonatal trauma.