Association between maternal thyroid function in early pregnancy and neurodevelopment in children aged 0–24 months: a retrospective cohort study

To investigate the influence of maternal thyroid function in early pregnancy on offspring neurodevelopment outcomes. We retrospectively analyzed 20,855 mother-offspring pairs from Shenzhen, China, with delivery dates between February 2016 and May 2024. Maternal thyroid hormone levels were measured at 7–13 gestational weeks. Neurodevelopment outcomes were assessed using the Ages and Stages Questionnaire-Third Edition (ASQ-3) at 0–24 months of age. Compared with euthyroid mothers, overt hypothyroidism was associated with an increased risk of gross motor delay (adjusted odds ratio [aOR] 2.14; 95% confidence interval [CI] 1.17–3.63). Subclinical hypothyroidism was linked to a higher risk of delay in the problem-solving domain (aOR 1.63; 95% CI 1.03–2.49). Hypothyroxinemia was associated with increased risk of delays in both the gross motor (aOR 1.73; 95% CI 1.04–2.70) and fine motor domains (aOR 1.69; 95% CI 1.01–2.66). Subclinical hyperthyroidism was associated with an elevated risk of gross motor delay (aOR 1.97; 95% CI 1.14–3.18). Maternal thyroid-stimulating hormone (TSH) levels exhibited a U-shaped relationship with the risk of neurodevelopmental delay in the gross motor domain. ( P -overall = 0.012; P -nonlinear = 0.003) Maternal overt hypothyroidism, subclinical hypothyroidism, hypothyroxinemia, and subclinical hyperthyroidism in early pregnancy are associated with neurodevelopmental delays in children. Notably, this association exhibits a U-shaped pattern, whereby both low and high TSH levels are linked to an increased risk of neurodevelopmental delay.