The effect of income pooling within a call group on rates of obstetric intervention

On July 1, 1997, the call group at a tertiary referral hospital in Ottawa changed its remuneration. The authors tested the hypothesis that change in an obstetric call group's remuneration from individual fee-for-service billing to equal sharing of the pooled group income would result in reduced rates of obstetric intervention.

Intervention rates were compared for the 12 months before (1678 births) and the 12 months after (1934 births) the change. Data were collected on onset of labour, indication for induction of labour, mode of delivery and neonatal outcome. Statistical analysis was performed with Wilcoxon's signed-rank test.

The mean rate of elective induction of labour was 38.6% in the year before the change and 33.3% in the year after the change (p = 0.01). There were small but statistically significant increases in the mean duration of labour and mean length of the second stage (p = 0.03).

Billing policy may affect clinical decisions. Our findings add weight to the literature showing increased intervention rates with fee-for-service remuneration.