Can Mild-to-Moderate Iodine Deficiency during Pregnancy Alter Thyroid Function? Lessons from a Mother-Newborn Cohort

Area of Science:

• Endocrinology
• Maternal-Fetal Medicine
• Nutritional Science

Background:

• Severe iodine deficiency in pregnancy is linked to adverse hormonal effects, including fetal brain damage.
• Limited and conflicting data exist on the impact of mild-to-moderate iodine deficiency on thyroid function during pregnancy.

Purpose of the Study:

• To investigate the association between iodine intake and maternal/neonatal thyroid function in a mild-to-moderate iodine-deficient region.
• To evaluate iodine status using multiple biomarkers and assess its relationship with thyroid hormones and thyrotropin.

Main Methods:

• Cross-sectional study involving 178 pregnant women.
• Assessed iodine intake via food frequency questionnaire, serum thyroglobulin (Tg), and urinary iodine concentration (UIC).
• Measured neonatal thyrotropin (nTSH) and maternal free triiodothyronine (FT3) levels.

Main Results:

• A significant inverse association was found between iodine intake and serum Tg levels (p < 0.01).
• Higher FT3 levels were associated with iodine intake below the estimated average requirement (OR = 2.6, p = 0.04).
• Women with higher FT3 were less likely to use iodine-containing supplements (OR = 0.3, p = 0.01).

Conclusions:

• Mild-to-moderate iodine insufficiency during pregnancy may affect maternal and neonatal thyroid function.
• Further research with larger sample sizes is warranted to confirm these findings.