Can Graves' disease affect ovarian function and egg production?

Impact of Graves' Disease on Ovarian Function and Egg Production

Graves' disease can affect ovarian function and potentially reduce fertility, but it does not typically cause complete inability to produce eggs. 1, 2

Thyroid-Reproductive Axis Connection

• Thyroid dysfunction, including Graves' disease (the most common cause of hyperthyroidism), can disrupt the hypothalamic-pituitary-ovarian axis, potentially affecting ovulation and menstrual regularity 1, 3
• Hyperthyroidism from Graves' disease can lead to menstrual disturbances, most commonly hypomenorrhea (light periods) and polymenorrhea (frequent periods) 1, 4
• According to recent studies, approximately 21.5% of women with thyrotoxicosis experience menstrual disturbances, which is significantly lower than the 50-60% reported in older studies 1

Fertility Impact in Graves' Disease

• Despite menstrual irregularities, most women with Graves' disease remain ovulatory based on endometrial biopsy findings 1
• While fertility may be affected, convincing evidence that fertility is significantly impaired in women with mild to moderate hyperthyroidism is lacking 2
• The peak incidence of Graves' disease occurs during reproductive years (second through fourth decades of life), making this a relevant concern for women of childbearing age 3, 2

Mechanism of Reproductive Effects

• In hyperthyroidism, altered estrogen metabolism and disruption of the hypothalamic-pituitary axis can affect normal reproductive function 5
• Thyroid hormone excess can alter sex hormone-binding globulin (SHBG) levels, which affects the availability of sex hormones 4
• Autoimmune mechanisms in Graves' disease may potentially affect other endocrine organs, though direct ovarian failure is not a typical feature 3

Treatment Considerations for Women of Reproductive Age

• Treatment options for Graves' disease include thioamide therapy (methimazole or propylthiouracil), surgery, or radioactive iodine 6
• For women planning pregnancy, achieving euthyroidism before conception is important to optimize fertility and pregnancy outcomes 7
• Radioactive iodine therapy, while effective for treating Graves' disease, should be withheld in pregnant women and those actively breastfeeding, but evidence suggests it does not cause reduced fecundity in future pregnancies 6, 1

Monitoring and Management

• Women with Graves' disease who are experiencing menstrual irregularities or fertility concerns should have thyroid function tests (free T4, TSH) monitored regularly 5, 7
• The goal of treatment is to maintain free T4 in the high-normal range using the lowest possible medication dosage to control symptoms 7
• Regular monitoring of thyroid function is essential, especially if planning pregnancy or undergoing fertility treatments 7

Important Caveats

• Untreated or poorly controlled hyperthyroidism poses greater risks to fertility and pregnancy outcomes than properly managed disease 5, 7
• Other autoimmune conditions may coexist with Graves' disease and independently affect fertility 5
• Distinguishing between the effects of Graves' disease itself versus its treatments on fertility is important when counseling patients 6