To study whether maternal thyroid disease in pregnancy is associated with pubertal timing in sons and daughters.
National birth cohort and health registers.
A total of 15,763 mothers and children from the Danish National Birth Cohort and its Puberty Cohort.
Register-based and self-reported information on maternal thyroid diseases during pregnancy (hyperthyroidism, hypothyroidism, benign goiter, or no thyroid disease [reference group]).
Main Outcome Measure(s)
The adjusted mean age difference (months) at attaining several self-reported pubertal milestones collected every 6 months using an interval-censored regression and the average difference in age at attaining all pubertal milestones using the Huber-White robust variance estimation (primary outcome).
Sons of mothers with hyperthyroidism had earlier pubertal development (average difference, −2.9 [95% confidence interval (CI), −5.0 to −0.7] months) than unexposed sons. Maternal hypothyroidism was not associated with pubertal development in sons (average difference, −1.2 [95% CI, −5.1 to 2.7] months). We observed nonstatistically significant indications of earlier pubertal development in sons of mothers with benign goiter (average difference, −1.9 [95% CI, −4.6 to 0.9] months). Maternal thyroid disease was not associated with pubertal development in daughters (average difference (months), hyperthyroidism, −0.8 [95% CI, −2.8 to 1.2]; hypothyroidism, 0.3 [95% CI, −3.1 to 3.8]; and benign goiter, 0.7 [95% CI, −2.0 to 3.4]).
We found indications of earlier pubertal development in sons of mothers with hyperthyroidism. More research is needed to further investigate the observed sex-specific association.