To determine if interobstetrician variation in caesarean section rates was associated with different approaches to the management of labour.
A retrospective cohort study.
A tertiary care teaching hospital in Quebec, Canada.
546 nulliparae in spontaneous labour at term were grouped according to the rate of caesarean sections for dystocia of their obstetrician (high: women of two obstetricians with rates of 13.2% and 15.0%; and low: women of three obstetricians with rates of 6.0%, 6.2% and 6.5%).
Frequency and timing of oxytocin, epidural, amniotomy, forceps.
Indicators of neonatal asphyxia and trauma.
No difference between groups was observed in the frequency or timing of use of oxytocin or epidural analgesia. Amniotomy was practised earlier by the obstetricians in the high group. Differences in section rates for dystocia were greatest in the second stage (low-2.4%, high-7.9%). Obstetricians in the low group intervened earlier with forceps or vacuum extractor. Nine babies (all in the low group), 8 of whom had had an instrumental vaginal delivery, suffered trauma (5 clavicular fractures, 4 facial palsies) (Fisher's exact test, P = 0.0139).
The practice patterns of the two groups are distinguished by differences in management of the second stage. Although lower section rates were associated with an increase in mild neonatal trauma, this appears to have been mediated by the earlier use of forceps in this group.