Declining birth rates, increasing maternal age and neonatal intensive care unit admissions.

Abstract

To describe the number of US births, maternal age at birth and NICU admissions by maternal age cohorts. Our study aims to measure NICU utilization by maternal age over time. We queried the CDC WONDER Natality database for births, NICU admissions, and maternal age at delivery from 2016 to 2021. Births and NICU admissions were analyzed by maternal age. Between 2016 and 2021, US births decreased by 7% (3,945,875 to 3,664,292/year). NICU admissions increased from 344,454 to 351,775 (+2%) and admit rate from 8.7% to 9.6%. The proportion of births by maternal age declined each year for ≤29 y but increased for ≥30 y. NICU admission rates were lowest at maternal age 20-29 y and increased with age ≥30 y. US NICUs have demonstrated a 2% increase in admissions despite a 7% decrease in births. Higher rates of NICU admissions among infants born at maternal age ≥30 y warrants investigation.