To understand the relationships between Delivery Unit size, activity, nurse staffing and perinatal outcomes.METHODS:
From an observational cohort, including 101,120 pregnancies in 24 hospitals, we evaluated: Postpartum hemorrhage, 5-minute Apgar below 4 (LoAp5), Hypoxic Ischemic Encephalopathy (HIE), Shoulder dystocia (SD), Fetal trauma, and cord pH below 7.0. These were evaluated according to; Weekday vs Weekend, Night vs Day vs Evening shift, Small (below 3,500) vs Medium (3,500–5,499) vs Large (above 5,500) Unit size in births per year, and Nurse-Patient Ratio (NPR=Total nursing hours per shift/births per shift/8 hours). Scheduled cesareans, those delivering outside L&D, non-presenting newborns in multiple gestations, and neonatal deaths without resuscitation were excluded.RESULTS:
There were more births (P=.001) on Weekdays than Weekends (13.0 vs 10.7) and on Days than Nights (4.4 vs 3.5). There were wide ranges in daily birth volumes regardless of Unit size (Small 0–21, Medium 0–24, Large 0–56), although variance was greatest in Large Units (P=.001). NPR was higher on Weekends, Nights, and in Small vs Medium and Large Units, P=.001 for each. Multivariable regression revealed less LoAp5 (P=.04) and HIE (P<.001) on Days than Nights; more SD on Weekdays (P=.03); and less HIE (P=.009) and SD (P<.001) with increasing Unit size. The frequencies of adverse perinatal complications did not vary with NPR.CONCLUSION:
Birth volumes vary according to weekday and shift, with high daily variability regardless of Unit size. Nurse-Patient Ratios are higher in smaller Units, and during less busy Weekends and Nights. Within this context, NPR is not associated with adverse perinatal outcomes.