Objective We wanted to assess the incidence of intrauterine growth restriction (IUGR) in babies who are admitted to neonatal intensive care at or after 34 weeks, and compare their length of stay with those whose birthweight was appropriate for gestation.

Methods Regional database of singleton neonates excluding congenital anomalies, born during 2008/2009 from 34 or more weeks and subsequently admitted to one of 18 neonatal units. Length of stay was stratified by gestational age at birth. IUGR was defined as a birthweight below the 10th customised centile, adjusted for maternal constitutional characteristics as well sex of the baby and gestational age at birth.

Results There were 94,508 births during the period of investigation, and 5325 admissions at or after 34 weeks (5.6%). The overall IUGR rate of these babies was 30.4%, and ranged from 20.8 to 42.2%, the highest rate being for babies born at 36 weeks. The average length of stay on the neonatal intensive care unit was significantly higher for babies who were IUGR at birth (12.5 days) than those who were not IUGR (8.2 days); p<0.01.

Conclusions Babies requiring intensive care after being born late in third trimester are more likely to have had intrauterine growth restriction, and the intensive care they require is longer if they were IUGR.