Associations between women's childhood maltreatment and thyroid function before and during pregnancy.

Maternal childhood maltreatment has been associated with complications during pregnancy and neurodevelopmental disorders in offspring. Thyroid dysfunction could be a mechanistic pathway underlying this relationship. The thyroid is vital for reproductive health in women, maintaining menstrual cycles, fertility, and pregnancy. However, little is known how childhood maltreatment affects thyroid function in women contemplating pregnancy and those who are pregnant. Participants were from the Nurses' Health Study 3, including 217 women contemplating pregnancy and 156 pregnant women, all reporting childhood maltreatment using a validated 28-item Childhood Trauma Questionnaire. Thyroid function tests were plasma thyroid-stimulating hormone (TSH), free triiodothyronine (FT3), free thyroxine (FT4), and anti-thyroperoxidase antibody (TPOAb). Regression analyses were conducted. Among women contemplating pregnancy (n = 217), childhood maltreatment was consistently associated with lower FT3 levels, but not with FT4, TSH, or TPOAb levels. FT3 levels were 5% to 7% lower in those with mild to severe childhood maltreatment compared to those without. Among pregnant women (n = 156), no significant associations were observed between childhood maltreatment and thyroid function. In conclusion, childhood maltreatment was associated with low thyroid function (e.g., FT3) among women contemplating pregnancy, but not among pregnant women. Future large, prospective, racially and ethnically diverse studies are needed to confirm our findings.