The relation of obstetrical volume and nursery level to perinatal mortality.

We investigated the relation of hospital delivery volume and nursery technology level to perinatal outcome in 226,164 White singleton births in Washington State, 1980-83. Level III facilities (neonatal intensive care unit) were defined by the state licensing commission. We defined the Level II (intermediate) and Level I (normal newborn) facilities using published criteria. Infants under 2000 gm born in Level III facilities had half the risk of perinatal death compared to those born in a Level I or II facility. No significant improvement was noted among level or volume groupings for normal birthweight infants. A loglinear regression model of hospital perinatal death rates showed that when birthweight and maternal risk were controlled, obstetrical volume added minimal explanatory power to level of nursery care.