Impact of Resident Overnight Duty Hour Changes on Obstetrical Outcomes: A Population-Based Cohort Study

To determine whether obstetrical patient outcomes have changed following the introduction of restricted resident work hours.

A population-based retrospective cohort study of the effects of restricted duty hours for residents in July 2013 at three academic hospitals in Toronto, ON using linked health care databases. The study included 6763 deliveries in the 2 years pre-exposure and 5548 deliveries in the 2 years post-exposure.

The primary outcome, planned prior to data collection, was a composite index of 29 maternal/fetal outcomes including maternal transfusion/postpartum hemorrhage, maternal infection, fetal mortality, NICU admissions, and surgical/obstetrical complications. There were seven secondary outcomes analysed: NICU admissions; neonatal death; maternal transfusion or postpartum hemorrhage; maternal infection; and three composite measures. A generalized estimating equation model, clustered by institution, was utilized to assess for differences post-intervention. We found no significant differences in baseline demographics between groups. After the implementation of duty hour restrictions, no significant difference was seen in the primary outcome. However, an increased incidence of composite maternal surgical/obstetrical outcomes (OR 1.191; 95% CI 1.037-1.367, P = 0.013) and transfusion/postpartum hemorrhage (OR 1.232; 95% CI 1.074-1.413, P = 0.003) was found. There were no significant differences in other secondary outcomes.

Since the implementation of resident duty hour restrictions, there was no overall change in patient outcomes. However, there was an increase in surgical/obstetrical complications and transfusion/postpartum hemorrhage. This suggests that duty hour restrictions may not be beneficial to patient outcomes. It highlights the need to further investigate the clinical impact of a change in resident duty hours.