While a fetus is developing, the mother supplies it with thyroid hormones until 18-20 weeks when the fetal thyroid gland is functionally mature. After that, the mother provides supplementary thyroxine (thyroid hormone) until birth. It’s known that in a developing fetus, this continuous supply of thyroid support from the mother is crucial as thyroid hormones aid in brain development by regulating gene expression in the central nervous system. It has been found through MRIs that the children of mothers with overt hypothyroidism (low thyroid functioning) during pregnancy have differences in the shape of their cortex and decreased volume in their hippocampus. These areas are associated with perception, memory, and executive function, so this study set out to discover the effects on the motor and cognitive development of children whose mothers have mild thyroid dysfunction during pregnancy. This study looked at the developmental milestones of 757 children from Crete, Greece at 18 months, 4 years, and 6 years of age. What was found was support for previous findings that maternal hypothyroidism during gestation is associated with decreased motor and verbal abilities in early childhood of children. They also found that maternal thyroid autoimmunity is also associated with impaired motor ability, perception, and non-verbal cognitive development in preschool-age children. While more research needs to be done on this subject, it points out a need for thyroid autoimmune care and checks to be of more concern during pregnancy.
Kampouri M, Margetaki K, Koutra K, et al
Maternal mild thyroid dysfunction and offspring cognitive and motor development from infancy to childhood: the Rhea mother-child cohort study in Crete, Greece
J Epidemiol Community Health 2021;75:29-35.