Thyroid disease may not show up until pregnancy.

Dear Mayo Clinic I am five months pregnant and have just been diagnosed with hypothyroidism. I have never had thyroid problems before. Is this diagnosis related to my pregnancy? Will my hypothyroidism go away after I give birth?

A: Hypothyroidism is most likely triggered by pregnancy, but the underlying cause is probably not the pregnancy itself. Some women with thyroid disease do not show symptoms until pregnancy. If symptoms do appear, it is important to seek medical attention and continue to be monitored for 6-9 months after delivery. After that, it is also important to have regular checkups to monitor thyroid function, especially if the woman becomes pregnant again.

The thyroid gland is a small butterfly-shaped gland located at the base of the front of the neck. The thyroid gland produces the hormones triiodothyronine (T3) and thyroxine (T4), which affect all aspects of metabolism. Thyroid hormones help maintain the rate at which the body uses fat and carbohydrates, control body temperature, affect heart rate, and regulate protein production.

Studies show that about 10% of young women have thyroid conditions that do not cause problems before pregnancy, but worsen and cause symptoms during pregnancy. Women with thyroid disease are often found to have high levels of antithyroid antibodies in their bodies – a condition known as chronic thyroiditis, Hashimoto’s disease or autoimmune thyroid disease. After childbirth, antibody levels usually rise and thyroid function may be temporarily impaired. This can happen during pregnancy as well.

As in your case, this thyroid disorder often leads to hypothyroidism, a condition caused by low levels of thyroid hormones in the body. Some common symptoms of hypothyroidism are difficult to notice during pregnancy because they resemble pregnancy signs such as weight gain, fatigue, and constipation. Other symptoms of hypothyroidism that are more obvious during pregnancy include sensitivity to cold, dry skin, facial swelling, muscle weakness, hoarseness of voice, joint pain and stiffness, poor concentration and memory.

Treatment of hypothyroidism with thyroid hormones (levothyroxine) is very important for people in your position, because untreated hypothyroidism can affect fetal development and the mother’s health during pregnancy. Thyroid function should be monitored closely during pregnancy, such as blood tests every 4-8 weeks.

In some women, the condition can lead to a disorder known as postpartum thyroiditis after pregnancy. This disorder can lead to hypothyroidism or hyperthyroidism, a condition caused by high levels of thyroid hormones in the body. Hyperthyroidism after pregnancy often goes away spontaneously without treatment.

However, if hypothyroidism develops after delivery, treatment is usually required for 6-12 months. After that, it can usually be discontinued. However, it’s important to remember that even if treatment successfully eliminates hypothyroidism in a case like yours, the underlying thyroid disease remains. This means that if you become pregnant again, no matter how much time has passed since your pregnancy, you will likely develop hypothyroidism again. Knowing this in advance will help you and your doctor work together to develop a treatment plan. By starting treatment early in pregnancy, you can often prevent the symptoms of hypothyroidism from appearing.

You should also plan to follow-up with your doctor to check your thyroid function over time, even if you don’t have any new pregnancies. Several studies have shown that women with thyroid disease that causes symptoms during and after pregnancy are at risk for developing other thyroid problems later in life. Regular checkups can detect thyroid dysfunction in its early stages and make it easier to treat.