Who’s in the NICU? A population-level analysis

To understand the characteristics of infants admitted to US NICUs.

2006–2014 linked birth certificate and hospital discharge data for potentially viable deliveries in Pennsylvania and South Carolina were used. NICU admissions were identified using revenue codes. NICU-admitted infants were categorized by gestational age (GA), birthweight, and condition severity (for GA 35+ weeks). We also assessed total patient days and trends over time.

12% of infants were admitted to a NICU; 13.6% were GA < 32 weeks (45.3% of total days); 36.1% were GA 32–36 weeks (31.2% of total days); and 50.4% were GA 37+ weeks (23.5% of total days). 20% of admissions were for infants with GA 35+ weeks and mild conditions. Admissions increased numerically from 11.2% (2006) to 13.0% (2014), with increases among infants 35+ weeks.

Most NICU admissions are for infants 35+ weeks GA, many with mild conditions who may be accommodated in well-baby units.