Hypothyroidism and Heavy Periods

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Hypothyroidism and Heavy Periods

Question:

Can hypothyroidism cause heavy and long periods? Will Levoxyl (L-thyroxine) help?

Answer:

Hypothyroidism is an underactive thyroid gland. It can definitely cause heavier and longer bleeding during menstrual periods. Doctors call heavier and longer menstrual bleeding menorrhagia.

Up to 15% of women will have some abnormality of the thyroid during their lives. Usually the problem is an underactive thyroid gland. Premenopausal women who develop hypothyroidism will develop heavier bleeding about 50% of the time. Often, menorrhagia is the first clue that a woman has hypothyroidism.

L-thyroxine (Levoxyl, Synthroid) is the most commonly prescribed medication to replace what the thyroid gland can no longer produce.

L-thyroxine and other types of thyroid preparations raise thyroid levels to normal and should stop the menorrhagia. If heavy bleeding persists despite adequate thyroid replacement, then another reason for the abnormal menstrual bleeding should be considered.

Howard LeWine, M.D., is chief editor of Internet Publishing at Harvard Health Publications. He is recognized as an outstanding clinician and teacher and is a recipient of the Internal Medicine Teacher of the Year award at Brigham and Women's Hospital. Dr. LeWine continues to practice Internal Medicine; most recently he became a hospitalist after practicing primary care for over 20 years.

Last updated:	July 20, 2009