More than 18,000 British infants born between September 2000 and August 2001, were examined in the study. The researchers assessed health outcomes, including height, weight and BMI, when the infants reached 9 months, 3 years and 5 years. In addition, parents reported the number of hospital visits, disability or infirmity, long-standing illness, overall rating of child's health, use of prescribed medication and wheezing.
Results from the study showed that both babies born at 32-36 weeks (moderate/late preterm) and 37-38 weeks (early term) required hospitalization in the first few months compared to those born at full term (39-41 weeks). In addition, the risk of wheezing and asthma was increased among babies born between 33 and 36 weeks compared to babies born at full term.
The researchers found a strong association between increasing risk of poor health outcomes and decreasing gestation, and that the greatest contribution to disease at age 3 and 5 was being born moderate/ later preterm or early term.
Furthermore, they discovered that mothers of children born less than 37 weeks were more likely to:
- Work in managerial positions
- Less likely to have educational qualifications
- Be single
According to the researchers it is incorrect to simply classify babies as preterm or term as the study shows a "continuum of increasing risk of adverse outcome with increasing prematurity, even approaching full term gestation."
They state that more explanation is needed regarding factors that impact health outcomes for infants born between 32-38 weeks gestation in order to inform the provision of obstetric services and planning and delivery of healthcare services for children in early life.