Is there a weekend effect in obstetrics?

Recent research published in The BMJ and elsewhere brings renewed attention to the “weekend effect,” suggesting higher rates of adverse outcomes associated with hospital admissions and procedures performed at weekends than on weekdays.1 2 3 Findings are not uniform among studies and fields of medicine, and persistent questions remain about whether significant findings reflect differences in case mix severity during the weekend or staffing and volume factors that are likely to influence outcomes among the patients at highest risk. The weekend effect is particularly under-studied in obstetrics, with decidedly mixed results from the small number of studies.4 5 6 7 A study by Palmer and colleagues (doi:10.1136/bmj.h5774) helps to fill this evidence gap, presenting a thoughtful analysis of adverse birth outcomes in a retrospective cohort from the United Kingdom.8

This study found that some adverse outcomes were slightly but significantly more common among weekend deliveries, most notably perinatal mortality. Although the magnitude was small (an unadjusted absolute increase of 0.9 deaths per 1000 deliveries …