Pre and Post-Term Births tied to increased Risk of Autism Spectrum Disorder

Tobetter understand potential links between gestational age and risk of ASD, Persson and colleagues analyzed medical registry data on more than 3.5 million children born in Sweden, Finland, or Norway between 1995 to 2015. Within that cohort, 1.44 percent of the children were diagnosed with ASD, and 4.7 percent were born pre-term—before 37 weeks of gestation.

Theanalysis, which covered gestational ages at birth ranging from 22 to 44 weeks, showed that overall risk of ASD was low for every age, especially for girls born post-term (after 42 weeks of gestation). However, the relative risk of ASD increased for each week of gestational age below or above 40 weeks.

Ofthe children born at term—in weeks 37 to 42—0.83 percent were diagnosed with ASD. The percentage was 1.67 for those born in weeks 22 to 31, 1.08 percent for weeks 32 to 36, and 1.74 for weeks 43 to 44. These differences in risk were independent of sex and birth weight for gestational age.

Thesefindings provide new insights into the potential links between risk of ASD and gestational age at birth—which is potentially modifiable. More research will be needed to clarify these links and investigate whether they could lead to strategies to lower risk by addressing pre-term birth.