Hypothyroxinemia in pregnancy linked to autism

A recent paper in The Lancet (volume 382:331-7) found that two-thirds of women in the UK were iodine deficient during pregnancy, placing them at risk of gestational hypothyroxinemia (abnormally low concentrations of thyroxine in the blood). Now Dutch research published in Annals of Neurology has linked severe gestational hypothyroxinemia to an increased risk of autism.

Researchers found severe maternal gestational hypothyroxinemia in approximately 3% of the 5100 women tested after, on average, 13.4 weeks' gestation.

Eighty children had probable autism. Babies born to women with severe gestational hypothyroxinemia were almost four times (odds ratio [OR] 3.89) more likely to be diagnosed with probable autism compared with controls. Furthermore, children born to mothers with severe gestational hypothyroxinemia were twice as likely to develop borderline (OR 2.02) and clinical (OR 2.60) pervasive developmental problems at six years of age.