A pregnant person may be more likely to develop hypothyroidism. If not treated, it can have several severe risks for both a pregnant person and the fetus. However, healthcare professionals can effectively treat hypothyroidism.

Hypothyroidism is when a person’s thyroid gland does not make enough thyroid hormones.

The thyroid is a small gland in the front of the neck. Thyroid hormones regulate many bodily functions. They also play important roles in how a fetus develops in the womb.

This article discusses if pregnancy can cause hypothyroidism and how hypothyroidism can affect pregnancy. It explains whether hypothyroidism can affect the fetus and a person’s fertility. It also outlines hypothyroidism treatment during pregnancy.

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Pregnancy can increase a person’s risk of developing thyroid conditions, including hypothyroidism. People who have been pregnant in the last 6 months may be more likely to have hypothyroidism.

Having an autoimmune disorder called Hashimoto thyroiditis often causes a pregnant person to develop hypothyroidism. Hashimoto thyroiditis is a condition where the immune system damages the thyroid gland. The thyroid gland then cannot make as much of the thyroid hormones, leading to hypothyroidism.

In pregnancy, the thyroid changes to help produce enough extra thyroid hormones for the fetus.

During the first trimester, a fetus depends on thyroid hormones supplied from a pregnant person’s thyroid gland. The first trimester is the first 3 months of pregnancy. After about 12 weeks, the fetus’s thyroid gland starts to work. It does not make enough thyroid hormones until 18 to 20 weeks.

Learn more about hypothyroidism.

Untreated hypothyroidism can affect pregnancy by causing complications such as:

These complications most often happen if a person has severe hypothyroidism. In rare cases, it may also cause heart failure. It can also increase a person’s risk of fatal complications during pregnancy.

If a person has subclinical hypothyroidism, they may not require treatment. Subclinical hypothyroidism is a mild form of the condition with no symptoms.

If a person who is pregnant has untreated hypothyroidism, it may affect the fetus in several ways, including:

  • slowed growth
  • lower IQ
  • hearing and speech problems
  • cognitive impairment, or problems with a person’s ability to:
    • think
    • learn
    • remember
    • use judgment
    • make decisions
  • motor impairment, partial or loss of function of body parts such as limbs
  • low birth weight

It may also lead to fatal complications for the fetus. However, treatment options are available to help prevent complications of hypothyroidism.

Hypothyroidism can affect the menstrual cycle and ovulation, which can lead to fertility issues. It can affect ovulation and the reproductive systems in both direct and indirect ways.

Untreated hypothyroidism during pregnancy can lead to subfertility. Subfertility is a medical term for infertility, where a person does not conceive after 1 year of regular sexual intercourse without any kind of birth control method.

Hypothyroidism treatments replace hormones that the thyroid can no longer produce or not produce enough of.

Healthcare professionals normally prescribe the thyroid hormone medication levothyroxine for pregnant people. Levothyroxine replaces a thyroid hormone called T4.

If a pregnant person has a thyroid condition, a healthcare professional will typically test their thyroid levels every 4 to 6 weeks for the first half of the pregnancy and then at least once after 30 weeks.

The healthcare professional may then adjust the medication dosage.

People with hypothyroidism who are taking levothyroxine before pregnancy may need an increased dose during pregnancy. People with subclinical hypothyroidism may not need treatment.

People with Hashimoto thyroiditis or other thyroid conditions may be sensitive to iodine side effects. They should speak with healthcare professionals about which foods, medications, or dietary supplements they may need to avoid.

The following are answers to some questions people frequently ask about hypothyroidism and pregnancy.

Is it safe to get pregnant with hypothyroidism?

Medical treatments can help people with hypothyroidism have healthy pregnancies. People with hypothyroidism should seek professional medical advice before and during pregnancy. Healthcare professionals can use medication and regular thyroid testing to help prevent complications.

Are you considered high risk pregnancy with hypothyroidism?

Untreated hypothyroidism during pregnancy can affect the health of a pregnant person and the fetus. For this reason, healthcare professionals may consider this to be a high risk pregnancy. However, thyroid medications can help prevent these effects.

Hypothyroidism is when the thyroid gland makes too few thyroid hormones. These hormones affect many bodily functions. A pregnant person’s thyroid gland changes to supply more thyroid hormones to the fetus. Pregnancy can make a person more likely to have hypothyroidism.

If not treated, hypothyroidism during pregnancy can have several complications, including anemia and high blood pressure. It may affect the development and health of the fetus or cause serious birth complications. Hypothyroidism can also affect fertility.

Healthcare professionals can effectively treat hypothyroidism using medication. This medication replaces the thyroid hormones the thyroid gland does not produce. Medical treatment and supervision from a healthcare professional can allow a safe pregnancy for a person with hypothyroidism.