Thyroid Function and Fertility in Women

Abstract

Thyroid hormones, by affecting prolactin and sex hormone-binding globulin levels and oocyte maturation, significantly affect reproductive function in women. Subclinical or overt hypothyroidism is most common, and hyperthyroidism is less common. Approximately 10% of women show immunological thyroid disorders with increased antibody levels. There is no conclusive data that fertility disorders accompany hyperthyroidism. Hypothyroidism in pregnancy is a factor in its risk, as therapy in the first trimester is proposed propylthiouracil. In contrast, thiamazole is recommended in the second and third trimesters due to its hepatotoxic effects. Breastfeeding should occur immediately after taking the drugs and 3 hours before the next feeding. Abnormalities in monthly bleeding and ovulation accompany hypothyroidism and are the most common cause of fertility and pregnancy disorders, especially when accompanied by elevated levels of anti-TPO antibodies. Medications used to treat hypothyroidism are not contraindicated for breastfeeding during pregnancy, and screening tests in the form of TSH, FT4, and anti-TPO determination are recommended for women planning pregnancy and who are pregnant.