Thyroid Disorders Thyroid Disease in Women

Although the reason is not understood, women are at a higher risk of most types of thyroid disease than men. They develop thyroid disorders early in life and about 10% of women will have thyroid dysfunction following pregnancy. These women will often have circulating antibodies to the thyroid gland and many have a medical history of insulin-dependent diabetes, rheumatoid arthritis, pernicious anemia, prematurely graying hair, vitiligo or other autoimmune disorder. Twenty-five percent of those with an autoimmune disorder will develop thyroid dysfunction. Thyroid dysfunction in the post partum period is also thought to play a role in some cases of post partum depression (see the section on pregnancy and infertility).

Puberty and Menstruation

Depending on the type of thyroid disease and the time of onset, high or low levels of thyroid hormone may cause either very early onset of menses (first menstrual period), also called precocious puberty, occurring before age 9, or delayed puberty, occurring after age 15. If hyperthyroidism occurs during childhood before puberty, the first menstrual period is usually delayed. However, when hyperthyroidism occurs during the early years of puberty, the first menses may begin early. McCune-Albright Syndrome is a rare disease affecting the bone and ovaries, which may occur when there is a combination of hyperthyroidism and precocious puberty. Hypothyroidism in adolescence is most commonly associated with delayed puberty and sometimes decreased stature (height). Very rarely, hypothyroidism in childhood is associated with precocious puberty with enlargement of the pituitary gland and other pituitary abnormalities such as the excessive production of a hormone called prolactin.

Thyroid disease may also be the result, rather than the cause, of menstrual abnormalities. Turner's syndrome is a genetic disease in which the ovaries do not form normally and do not contain eggs and a girl with Turner's syndrome cannot menstruate unless female hormone treatment is given. Furthermore, women with Turner's syndrome have an increased chance of having hypothyroidism.

After puberty, hyperthyroidism may cause infrequent and light periods, or they may cease altogether. In hypothyroidism, the periods often become too frequent and too heavy, sometimes with prolonged bleeding that may even result in anemia.

Premenstrual Syndrome (PMS)

Since hypothyroidism slows down virtually every process of the body, its symptoms often mimic those of premenstrual syndrome (PMS), including bloating, weight gain, mood changes (depression, irritability), changes in libido, sleep disorders, fatigue, malaise, and constipation. Women with hypothyroidism may notice improvement in their symptoms of PMS with thyroid hormone treatment. It is important to note that thyroid hormone medication only improves PMS in women with hypothyroidism because the decreased thyroid hormone levels exacerbate the existing PMS, it does not help most women with PMS only. Women who suffer from PMS should report their symptoms to their physician so that the thyroid function can be evaluated.

Sexual Function

Hyperthyroidism and hypothyroidism have been linked to mood disorders and decreased sexual desire (libido).

Menopause

Hypothyroidism occurs most frequently in women entering menopause, which typically occurs in their late 40s and early 50s. However, women with hyperthyroidism or hypothyroidism may have an earlier onset, or premature, menopause (occurring before age 40) with infrequent or absent periods. Often symptoms of hyperthyroidism, such as irregular or absent menses, heat intolerance, "hot flashes," insomnia, and mood swings may overlap with and be confused with symptoms of menopause and once the hyperthyroidism is controlled these symptoms may resolve, with the resumption of normal menstrual cycles and normal onset of menopause. This restoration of the menses results in a normal level of female hormones (estrogen) that is important for helping maintain the body's bone mass and decreasing the risk of osteoporosis.