Changes in menstruation due to thyroid

Some changes in the thyroid, such as hypo and hyperthyroidism, can interfere with the menstrual cycle, since there is an imbalance in the levels of hormones T3, T4 and TSH, which are hormones that directly influence the functioning of the female reproductive system, including concentration. of circulating estrogen and progesterone.

Thus, in the case of hypothyroidism, it is possible for the woman to have a more irregular menstrual cycle, with greater flow and more cramps, while in hyperthyroidism, it is more common to have a decrease in menstrual flow and, in some cases, amenorrhea, which is the absence of menstruation.

It is important that the gynecologist is consulted if any changes are observed in the menstrual period, as tests may be requested to identify the cause and initiate the most appropriate treatment.

How the thyroid affects menstruation

The possible changes that can occur in the menstrual cycle due to changes in the functioning of the thyroid are:

1. Hypothyroidism

Hypothyroidism is characterized by an increase in the concentration of circulating TSH and a decrease in T3 and T4 levels, which can lead to the following changes:

• Appearance of menstruation before the age of 10, which can happen because increasing TSH has a small effect similar to the hormones FSH and LH, which are responsible for regulating menstruation.;
• Early menstruation, that is, a woman who had a 30-day cycle may now have a 24-day cycle, for example, or menstruation may come at an off-time;
• Increased menstrual flow, called menorrhagia, it is necessary to change the pad more often throughout the day and, in addition, the number of days of menstruation may increase;
• More intense menstrual cramps, called dysmenorrhea, which causes pelvic pain, headache and malaise, and it may be necessary to take analgesics to relieve the pain.

Another change that can happen is difficulty getting pregnant, because there is a decrease in the luteal phase. In addition, galactorrhea may also occur, which consists of the release of ‘milk’ through the nipples, even if the woman is not pregnant.

2. Hyperthyroidism

Hyperthyroidism occurs when there is a lower amount of circulating TSH and a normal or higher concentration of T3 and T4, which can cause:

• Delay of first menstruation, when the girl has not yet had her menarche and already has hyperthyroidism in childhood;
• Delayed menstruation, due to changes in the menstrual cycle, which may become more spaced out, with a longer interval between cycles;
• Decrease in menstrual flow, which can be noticed in pads, because there is less bleeding per day;
• Absence of menstruation, which can last for several months.

After surgery to remove part of the thyroid, changes in menstruation may also occur. Right after the surgery, while still in the hospital, heavy bleeding may occur even if the woman is taking the continuous pill normally.

This bleeding can last 2 or 3 days, and after 2 to 3 weeks there may be a new period, which may come by surprise, and this indicates that the half of the thyroid that remained is still adapting to the new reality, and still needs adjust in relation to the amount of hormones you need to produce.

When to go to the doctor

An appointment with a gynecologist should be made if the woman presents the following changes:

• You are over 12 years old and have not yet menstruated;
• Go more than 90 days without menstruation, and if you are not taking the continuous use pill, nor are you pregnant;
• Suffer an increase in menstrual cramps, which prevent you from working or studying;
• Bleeding appears for more than 2 days, completely outside the menstrual period;
• Menstruation becomes more abundant than usual;
• Menstruation lasts more than 8 days.

The doctor may order TSH, T3 and T4 tests to assess thyroid hormones, in order to check whether there is a need to take medication to regulate the thyroid, as this will normalize menstruation. Find out about the tests that evaluate the thyroid.