Babies born from the 37th week of pregnancy who are mild to moderately small for gestational age (SGA) could benefit from monitoring to check for developmental problems, a study suggested.
A team of researchers at Coventry (England) University found that birth weight below the 25th percentile was associated with more developmental concerns in early childhood than a weight between the 25th and 74th percentile.
Those difficulties were apparent at percentiles higher than the conventional threshold defining SGA, they noted.
Low and high extremes of birth weight have been associated with adverse pregnancy and neonatal health outcomes, but little is known about the effects on motor skills, socialization, language, and other developmental markers for the entire range of birth weights for nonpremature babies.
Study linked health databases to child assessment results
To find out more, researchers conducted a population-based cohort study of 686,284 singleton infants born from 37 weeks of gestation, linking pregnancy and birth records from health databases covering all of Scotland to child development assessments carried out between the ages of 2 and 3.5 years.
The researchers looked for associations between birth weight and early childhood developmental concerns, taking into account confounders, such as maternal age, the mother’s medical history during pregnancy, early pregnancy body mass index, deprivation, ethnicity, alcohol use, and smoking history.
The study, published in the open access journal PLOS Medicine, found that babies born below the 25th percentile for birth weight had a higher risk of developmental concerns, compared with babies born between the 25th and 74th percentiles, with the infants who had the lowest birth weight most at risk of later developmental difficulties.
Those born between the 10th and 24th percentile had a relative risk of 1.07 (95% confidence interval, 1.03-1.12; P < .001); between the 3rd and 9th percentile, the RR was 1.18 (95% CI, 1.12-1.25, P < .001), and below the 3rd percentile the RR was 1.37 (95% CI, 1.24-1.50; P < .001).
No substantial increase in the risk of early childhood developmental concerns was identified for larger birth weight categories in the 75th-89th percentile range, the researchers reported.
Monitoring and support
The researchers concluded that having mild to moderate SGA “is an unrecognized, potentially important contributor to the prevalence of developmental concerns.”
Before this study, babies below the 10th percentile were usually considered at risk for developmental concerns. However, the investigation found a greater number of babies within the 10th-24th percentile range of birth weights with these issues, simply because there were a larger number of babies within that population.
Abiodun Adanikin, MBBS, PhD, MPH, of Coventry University’s Centre for Healthcare Research, and study first author, said: “Though it is mostly unrecognized, babies who are mild to moderately small at birth are key contributors to the burden of childhood developmental concerns. They may need closer monitoring and increased support to reduce the risk of developmental concerns.”
The study also involved colleagues from the University of Bristol (England), the University of Glasgow, the University of Cambridge (England), and Queen Mary University of London.
This work was supported by a Wellbeing of Women Research Grant. One author has received research support from Roche Diagnostics, GSK, Illumina, and Sera Prognostics (fetal growth restriction, preeclampsia and preterm birth). He has been a paid consultant to GSK (preterm birth) and is a member of a Data Monitoring Committee for GSK trials of RSV vaccination in pregnancy. He is one of three named inventors on a patent application filed by Cambridge Enterprise for novel predictive test for fetal growth disorder. He is an academic editor on PLOS Medicine’s editorial board. The authors declare no other competing interest.
A version of this article first appeared on Medscape UK.