Maternal thyroid-stimulating hormone (TSH) concentrations in early pregnancy are associated with the volume of grey matter in offspring at 9-12 years of age, according to a novel study finding.

The Dutch prospective study of 1981 mother-child pairs showed that both low and high maternal TSH influences neurodevelopment in the fetus in a small window between eight and 13 weeks’ gestation.

“To the best of our knowledge, this study is the first to show that the association of maternal thyroid function with offspring neurodevelopment attenuates from early pregnancy onwards, suggesting that this is the most vulnerable period of the fetus for low or high maternal thyroid function,” said the researchers, led by Professor Henning Tiemeier from Erasmus Medical Centre in Rotterdam.

Previously, both hypo- and hyperthyroidism in early pregnancy have been linked to lower IQ, and an increased risk of schizophrenia, autism and attention deficit hyperactivity disorder.