Babies born just two or three weeks early at higher risk of poor health

The authors, from the Universities of Leicester, Liverpool, Oxford, Warwick and the National Perinatal Epidemiology Unit studied over 18,000 British babies born between September 2000 and August 2001. Health outcomes were studied when the infants reached nine months, three years and five years.

Health outcomes assessed included height, weight and BMI, whilst parents also reported on number of hospital visits, long-standing illness, disability or infirmity, wheezing, use of prescribed medication and overall rating of child's health.

The authors report that both moderate / late preterm (32-36 weeks) and early term (37-38 weeks) babies required re-admission to hospital in the first few months more often than full term babies (39-41 weeks). Those born between 33 and 36 weeks had an increased risk of asthma and wheezing compared to full term babies.

A strong correlation was found between decreasing gestation and increasing risk of poor health outcomes. The greatest contribution to disease at the age of both three and five was being born moderate / late preterm or early term. The study discovered that mothers of children born at less than 37 weeks were more likely to be single, less likely to have educational qualifications or work in managerial positions. Mothers of very preterm babies were more likely to smoke and less likely to breast feed for four or more months than those delivered at or beyond 37 weeks.

The authors conclude that it is inappropriate simply to group babies as preterm or term as the study demonstrates a "continuum of increasing risk of adverse outcome with increasing prematurity, even approaching full term gestation." They argue for further explanation of factors that influence health outcomes for babies born between 32-38 weeks gestation to inform the provision of obstetric services and planning and delivery of healthcare services for children in early life.