Thyroid Disorders

The thyroid is a vital gland that regulates many bodily functions. If it does not function properly, most organs are negatively affected. The reproductive organs are among the first to be affected. Since an underactive or overactive thyroid directly affects the reproductive hormones in both women and men, it is one of the primary causes of infertility.

Thyroid hormones directly affect hormones

Thyroid hormones interact with all hormones in the body, particularly sex hormones. For the ovaries in women and the testes in men to function normally, thyroid hormone levels must be within the normal range. Low thyroid levels not only contribute to infertility but can also negatively affect the baby’s development in the womb. Thyroid hormones account for 30% of male infertility cases and 35% of female infertility cases.

How do hypothyroidism and hyperthyroidism affect pregnancy?

An underactive thyroid gland (hypothyroidism) lowers the levels of FSH and LH—the hormones that trigger ovulation—and raises the level of prolactin, commonly known as the “milk hormone.” This prevents healthy ovulation. Additionally, in pregnant women with an underactive thyroid, miscarriage, premature birth, and low birth weight are common occurrences. An overactive thyroid (hyperthyroidism), on the other hand, causes ovulation problems and prevents conception.

For women known to have thyroid disease prior to pregnancy, it is absolutely essential to ensure their hormone levels are under control. If prospective parents with thyroid disease wish to conceive, they must be monitored by an Endocrinology and Metabolic Diseases specialist to plan an appropriate treatment regimen. The primary principle for thyroid patients during pregnancy is ensuring that thyroid hormone levels remain within normal ranges throughout the pregnancy until delivery. For this reason, expectant mothers with thyroid disease should be monitored through a multidisciplinary approach by an Endocrinology and Metabolic Diseases Specialist, an Obstetrician, and a High-Risk Pregnancy Specialist.

References:

• American Thyroid Association. (2017). Guidelines of the American Thyroid Association for the Diagnosis and Management of Thyroid Disease During Pregnancy and the Postpartum.

• Endocrine Society. (2012). Management of Thyroid Dysfunction during Pregnancy and Postpartum: Clinical Practice Guideline.

• American College of Obstetricians and Gynecologists. (Güncel). Thyroid Disease in Pregnancy – Practice Bulletin.

• European Thyroid Association. (2014). Guidelines for the Management of Subclinical Hypothyroidism in Pregnancy and Infertility.

• Turkish Society of Endocrinology and Metabolism. (Updated). Guidelines for the Diagnosis and Treatment of Thyroid Disorders.

• Turkish Society of Gynecology and Obstetrics. (Updated). Guide to Thyroid Disorders in Pregnancy.