Thyroid disease and female reproduction

Area of Science:

• Endocrinology
• Reproductive Health
• Nuclear Medicine

Background:

• Thyroid dysfunction, encompassing hyperthyroidism and hypothyroidism, is known to affect reproductive health.
• Traditional understanding suggests significant menstrual disturbances and fertility issues in patients with thyroid disease.
• Radioiodine (131I) therapy is a common treatment for Graves' disease and thyroid cancer, raising concerns about its impact on fertility and pregnancy.

Purpose of the Study:

• To review menstrual function and fertility in hyperthyroidism and hypothyroidism.
• To assess the effects of radioiodine (131I) therapy on fertility and subsequent pregnancies in patients with Graves' disease and thyroid cancer.

Main Methods:

• A comprehensive MEDLINE computer search was conducted to identify relevant studies.
• Data on menstrual disturbances and fertility status were extracted from selected studies.
• Fertility and genetic risks associated with (131)I therapy were specifically registered.

Main Results:

• Menstrual abnormalities in hyperthyroidism and hypothyroidism are less frequent than previously reported, with hypomenorrhea and oligomenorrhea being most common.
• Most thyrotoxic women remain ovulatory, and radioiodine therapy for Graves' disease and thyroid cancer presents a very small genetic hazard.
• Fertility is not reduced by (131)I exposure, and the risk of fertility loss is not a contraindication for its use.
• In hypothyroidism, menstrual irregularities are also less common than historically believed, with oligomenorrhea being the most frequent manifestation.
• Severe hypothyroidism is linked to ovulation failure, while mild cases allow for ovulation and conception, though pregnancies may have increased risks of abortion, stillbirth, or prematurity.

Conclusions:

• Current data on menstrual abnormalities in hyperthyroidism and hypothyroidism contradict established textbook information.
• The findings suggest a need to revise traditional beliefs regarding the impact of thyroid disease on menstrual function and fertility.
• Radioiodine therapy for thyroid conditions is safe concerning fertility and subsequent pregnancies.