Impact of maternal subclinical hypothyroidism during the first trimester on brain development of the offspring: a prospective study / 中华内分泌代谢杂志

ABSTRACT

Objective To assess the effects of maternal subclinical hypothyroidism (SCH) during the first trimester on neuropsychological development of the offspring by 20-30 months. Methods In this study, 1 761 pregnant women from 10 hospitals with about 8 weeks of gestation were enrolled. Urinary iodine excretion and serum thyrotropin ( TSH ), free thyroxine ( FT4 ), and thyroid peroxidase antibody ( TPOAb ) levels were determined in all subjects. Pregnant women with SCH (TSH≥2.5 mIU/L) were divided into two subgroups using trimester-specific thyroid function reference group A (2.5 mIU/L≤TSH＜3.93 mIU/L, 18 cases), and group B (TSH ≥3.93 mIU/L, 20 eases). Thirty euthyroid and TPOAb-negative women from the same cohort were selected as controls. Intellectual and motor development score evaluations were performed in the children by 20-30 months of age. Results Children of women with SCH and subgroups A and B had lower mean intelligence scores 6.55,3.39, and 9.40 points compared with those of the control group (P=0. 001, P=0. 125, and P＜0. 001 ); the respective mean motor scores were 6.31,4.35, and 8.07 points being lower than that of the control ( P=0. 003,P=0. 070, and P=0. 001 ). Intelligence scores and motor scores were negatively correlated with TSH levels (r=-0.425, P＜0. 001 and r=-0. 394, P=0. 001 ). Multiple group comparisons revealed that differences of TSH affected intelligence and motor scores (F=9. 277, P＜0. 001 and F=5. 909, P=0. 004). Ordinal logistic regression analysis showed that possibilities for the reduction of filial mental development index ( MDI ) and psychomotor development index ( PDI ) scores in SCH with maternal TSH levels≥3.93 mIU/L were 8.66 and 6.27 times that of controls ( OR = 8.66,95% CI 2.72-27.57, OR =6.27,95% CI 2.03-19.34 ). Conclusion Maternal elevated TSH levels diagnosed by trimester-specific reference during early gestation are independently associated with lowered filial neurodevelopment scores by 20-30 months.