The thyroid is a gland located in the neck that creates hormones responsible for making the metabolism function normally. The connection between the thyroid and menstruation varies, depending on whether a woman’s thyroid is working normally, working too much, or not working hard enough. If the thyroid is functioning the way it should, it will most likely have no effect on a woman’s menstruation cycle at all. An overactive thyroid, also known as "hyperactive," or an underactive thyroid, known as "hypoactive," can both lead to abnormal menstruation cycles, as well as other problems.
When a person’s thyroid is overactive, it is known as hyperthyroidism. As a result of this condition, a woman’s thyroid can produce more hormones than her body needs. Girls who have an overactive thyroid and menstruation problems may not get their period until after they are 15 years old. Women who experience this problem will normally have very irregular and very light periods.
When referring to the thyroid and menstruation, an excessive amount of thyroid hormones often means that a woman may develop amenorrhea or oligomenorrhea. The problem of amenorrhea refers to the complete absence of a menstrual cycle in a women. There are two different kinds of amenorrhea; the first is called primary amenorrhea, in which a women has never developed a period, and the other is secondary amenorrhea, where a woman’s menstrual cycle begins, but then stops occurring. Oligomenorrhea, on the other hand, is the condition of infrequent periods, diagnosed when a woman has only six to eight periods in an entire year.
Another problem that occurs because of the connection between the thyroid and menstruation is hypothyroidism. In this condition, the thyroid does not produce enough of the hormones that the body needs, so the metabolism becomes much slower. Many young girls who have this problem start their periods before the age of ten. This condition can lead to symptoms such as weight gain, fatigue, depression, and mood swings and will often lead to heavy periods and periods that occur much more often than they normally should.
Women who suffer from an underactive thyroid and menstruation problems sometimes develop a problem known as menorrhagia. With this problem, a woman’s periods can become much heavier and occur for longer periods of time. Another problem that can occur is dysmenorrhea, which causes extremely painful periods. This issue can cause very bad cramps and pain in a woman’s arms, legs, back, and head. Problems may also occur with a person's bowels because of dysmenorrhea, causing irregular bowel movements.