Effect of thyroid function on offspring neurodevelopment in people receiving ART therapy: a prospective cohort study

Abstract Context Adequate maternal thyroid hormone is vital for fetal neurodevelopment. Abnormal thyroid function can cause developmental defects in offspring from spontaneous pregnancies; however, research in assisted reproduction is lacking. Objectives To investigate the association between thyroid disorders and offspring neurodevelopment from assisted reproduction. Design Prospective cohort study. Setting and Participants In this prospective and longitudinal birth cohort study (Jiangsu, China), we included 729 women who had their thyroid function tested before ART cycle and delivered liveborn babies between November 2015 and June 2020. Main Outcome Measures Maternal thyroid function was assessed by measuring thyroid antibodies, free thyroxine, and serum thyroid-stimulating hormone. The third edition Bayley Scales of Infant and Toddler Development screening test (Bayley-III screening test) is used to assess the infant's neurodevelopment. Results In multivariate corrected linear regression analysis, infants of women with subclinical hypothyroidism demonstrated a significantly lower receptive communication score (β = -0.63, 95% CI [-1.12, -0.14], P = 0.013), with stratified analysis showing a significant association among female offspring (β = -0.87, 95% CI [-1.59, -0.15], P = 0.018) but null association among male offspring (β = -0.44, 95% CI [-1.03, 0.15], P = 0.145). No significant differences were found in assisted pregnancy population with normal thyroid function and positive antibodies according to the diagnostic cut-offs applied to normal pregnant women. Conclusions Subclinical hypothyroidism in assisted pregnancies correlates with lower communication scores in 1-year-olds, especially in girls. Recommending medication for subclinical hypothyroidism throughout, regardless of thyroid autoantibody status.