About the research
Thanks to advances in modern medicine, the chance of babies surviving if they are born prematurely is high, and being born as early as 32 weeks is no longer the automatic death sentence it once was. However there is a concern that children surviving such early births will suffer from ill-health and developmental effects. To address these concerns some researchers have been using longitudinal data to investigate whether a premature birth has these negative consequences on child development. They compared children born in one of four pre-term gestational ages (each stage being an increasingly shorter gestational period) with those children born at full-term (with 39-41 weeks gestation). These groups were:
- Early term (37-38 weeks)
- Late pre-term (34-36 weeks)
- Moderately pre-term (32-33 weeks)
- Very pre-term (32 weeks or less)
They discovered that the higher the prematurity, the greater risk of these ill effects, however the differences between each group were small. Those children born 33 to 36 weeks premature (late or moderately pre-term) were the most likely to have a higher disease burden at ages 3 and 5. Compared with full-term births those born in late pre-term or early term also had poorer health and educational outcomes at ages 3 and 5.
Methodology
Data on gestational age were determined from the maternal report included in the first survey of the Millennium Cohort Study and the data in the hospital records dataset. Logistic regression was conducted on each of the gestational age groups listed above. The analysis took into account the clustered study design of the Millennium Cohort Study.
Publications
Boyle, E.M., Poulsen, G., Field, D.J., Kurinczuk, J.J., Wolke, D., Alfirevic, Z., and Quigley, M.A. (2012) ‘Effects of gestational age at birth on health outcomes at age 3 and 5 years of age: Population based cohort study’, British Medical Journal 344. doi: 10.1136/bmj.e896 Retrieved 2 September 2013 from http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3291750/
Poulsen, G., Kurinczuk, J.J., Wolke, D., Boyle, E.M., Field, D., Alfirevic, Z., and Quigley, M.A. (2011) ‘Accurate reporting of expected delivery date by mothers 9 months after birth’, Journal of Clinical Epidemiology 64(12), pp. 1444-1450. doi: 10.1016/j.jclinepi.2011.03.007
Quigley, M.A., Poulsen, G., Boyle, E., Wolke, D., Field, D., Alfirevic, Z., and Kurinczuk, J.J. (2012) ‘Early term and late preterm birth are associated with poorer school performance at age 5 years: A cohort study’, Archive of Disease in Childhood, Fetal and Neonatal 97(3), pp. F167-F173. doi: 10.1136/archdischild-2011-300888