Objective To investigate the associations of maternal thyroid hormone (TH) levels during early pregnancy with neonatal anthropometric measures and anogenital distance (AGD), so as to provide reference for maternal and child health. Methods A total of 772 mother-infant pairs from the Jiashan Birth Cohort established between September 2016 and April 2018 were included, with available data on first-trimester TH levels, neonatal anthropometric measures, and AGD. Weight-for-age Z-score (WAZ), length-for-age Z-score (LAZ), head circumference-for-age Z-score (HCZ), and weight-for-length Z-score (WLZ) were calculated according to the WHO Child Growth Standards. Multivariate linear regression models were used to examine the associations between maternal TH levels and neonatal anthropometric indicators, and sex-stratified analysis was conducted for AGD outcomes. Results Compared with the medium free triiodothyronine (FT3) group (4.19 - 4.98 pmol/L), neonates in the high FT3 group (>4.98 pmol/L) had higher WAZ (β=0.23, 95%CI: 0.07 to 0.38), LAZ (β=0.06, 95%CI: 0.00 to 0.12), HCZ (β=0.24, 95%CI: 0.05 to 0.42), and WLZ (β=0.28, 95%CI: 0.05 to 0.51). Low maternal FT3 (<4.19 pmol/L) was associated with a longer AGDAP in male neonates (β=1.59, 95%CI: 0.20 to 2.99,P<0.05), whereas no significant association was observed in female neonates(P>0.05). Results from the thyroid antibody-negative subgroup were generally consistent with the main analysis. Conclusions Higher maternal FT3 levels during early pregnancy were associated with higher neonatal WAZ, LAZ, HCZ, and WLZ, while lower FT3 levels were associated with a longer AGDAP in male neonates. No clear association was observed between maternal TH levels and AGD in female neonates. These findings provide additional epidemiological evidence for the associations of maternal thyroid function during early pregnancy with offspring anthropometric development at birth and early reproductive development indicators.
Key words
thyroid hormones /
anogenital distance /
neonatal anthropometric measures /
prospective cohort study
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