Background: A frequent dilemma for obstetricians is how to keep morbidity to a minimum when faced with arrested progress at full dilatation of the cervix. Our aim was to examine maternal and neonatal morbidity associated with vaginal instrumental delivery in theatre and caesarean section, at full dilatation.
Methods: We did a prospective cohort study of 393 women, who had term, singleton, liveborn, cephalic pregnancies requiring operative delivery in theatre at full dilatation for 1 year.
Findings: Factors increasing the likelihood of caesarean section included maternal body-mass index greater than 30 (adjusted odds ratio 2.4, 95% CI 1.2-4.9), neonatal birthweight greater than 4.0 kg (2.3, 1.3-3.8), and occipitoposterior position (2.5, 1.6-3.9). Women undergoing caesarean section were more likely to have a major haemorrhage (>1 L; 2.8, 1.1-7.6) and extended hospital stay (>/=6 days; 3.5, 1.6-7.6) than those with vaginal delivery. Babies delivered by caesarean section were more likely to require admission for intensive care (2.6, 1.2-6.0) but less likely to have trauma (0.4, 0.2-0.7) than babies delivered by forceps. Overall neonatal morbidity was low, but a few babies in each group had serious complications (serious trauma, eight vs three; sepsis, six vs 13; and jaundice, ten vs 12 after vaginal delivery and caesarean section, respectively). Major haemorrhage was less likely after delivery by a skilled obstetrician (0.5, 0.3-0.9).
Interpretation: The data lend support to an aim to deliver women vaginally, unless there are clear signs of cephalopelvic disproportion, and underline the importance of skilled obstetricians supervising complex operative deliveries.