HealthDay News — Preterm and postterm birth are associated with an increased risk for autism spectrum disorder (ASD), according to a study published online Sept. 22 in PLOS Medicine.
Martina Persson, M.D., Ph.D., from the Karolinska Institutet in Stockholm, and colleagues examined the risk for ASD across the range of gestational ages (GAs) while adjusting for sex and size for GA. Children were followed from birth for a clinical diagnosis of ASD. Data were included for 3,526,174 singletons born from 1995 to 2015, including 1.44 percent with ASD.
The researchers found that 4.7 percent of the cohort were born preterm. The relative risk for ASD increased by each week of GA from 40 weeks to 24 weeks (preterm) and from 40 weeks to 44 weeks (postterm). For children born in weeks 22 to 31, 32 to 36, and 43 to 44 compared with weeks 37 to 42, the relative risks for ASD were estimated at 2.31, 1.35, and 1.37, respectively.
“Given the unknown etiology of ASD and the lifelong consequences of the disorder, identifying groups of increased risk associated with a potentially modifiable risk factor is important,” the authors write. “Whether risks of ASD in offspring born near term could be avoided by delivery at 40 weeks of gestation remains to be investigated.”
The study was partially funded by the Novo Nordisk Foundation.