Thyroid Problems and Pregnancy: Symptoms and Possible Consequences

Thyroid Problems and Pregnancy: Symptoms and Possible Consequences

Last update: 06 March, 2018

The thyroid gland carries out many important functions in our bodies. Pregnancy places extra demand on this gland, which can result in the appearance of thyroid problems for mother and baby.

The thyroid gland’s function is to produce triiodothyronine (T3) and thyroxine (T4). These two very important hormones regulate metabolism and body temperature. They also contribute to the functions of the brain, heart and muscles, as well as other tasks related to fertility and reproduction in women.

After conception, however, this small gland located just below the Adam’s apple must work overtime. The thyroid gland is forced to increase its production of thyroxine. This is because some of the hormone is transferred to the fetus until the baby produces his own.

In other words, the thyroid may produce enough hormones for both mother and baby. There are other connections between pregnancy and the thyroid gland as well. Continue reading to find out more.

The T4 hormone is responsible for processing the nutrients you consume and turning them into energy. But it’s also one of the hormones that contributes to the formation of the placenta.

Since the fetus does not develop its own thyroid until the 12th week of pregnancy, the mother must supply the necessary hormones both for her and the baby. 

Thyroids and pregnancy

During gestation, the production of T3 increases by about 30%, while the production of T4 increases by about 50%. 

Chorionic gonadotropin, the hormone detected by pregnancy tests, is responsible for producing the stimulation of the thyroid gland. From the second trimester of pregnancy and on, estrogen also alters the production of this hormone.

Alterations in the thyroid gland prior to pregnancy, as well as those that appear in gestation can cause issues during pregnancy.

“During gestation, the production of T3 increases by about 30%, while the production of T4 increases by about 50%”

Hypothyroidism during pregnancy

When the thyroid gland does not produce a sufficient amount of thyroxine to face the demands of pregnancy, this is called hypothyroidism.

In this case, a medical professional usually prescribes oral medication to the expecting mother in order to compensate for the shortage.

A pregnant women that is experiencing this insufficiency can also increase her iodine intake by adding iodized salt to her diet. Iodized salt boosts the production of hormones.

Thyroid Problems and Pregnancy: Symptoms and Possible Consequences
The following symptoms are an indication that you may be dealing with hypothyroidism:
  • Fatigue
  • Weakness
  • Weight gain
  • Constipation
  • Muscle and join pain
  • Dry skin
  • Weakening of the skin and nails

The combination of hypothyroidism and pregnancy can result in the fetus developing a goiter – or thyroid tumor – following the growth of its own thyroid gland. However, the goiter will disappear just days after the baby is born.

Hypothyroidism becomes dangerous during pregnancy when it is not treated on time (before the third trimester). A women with untreated hypothyroidism runs the risk of miscarriage, premature birth, hypertension and preeclampsia.

Hyperthyroidism during pregnancy

The opposite of hypothyroidism is hyperthyroidism. Hyperthyroidism in pregnancy refers to a production of hormones by the thyroid gland that exceeds the amount needed for gestation. 

The percentage of women that suffer from hyperthyroidism during pregnancy is very low – only about 2 in every 1000 women.

What are the symptoms that indicate the possible existence of hyperthyroidism during pregnancy? Here is a list of the most common signs:

  • Tachycardia
  • Weight loss
  • Trembling
  • Irregular intestinal function
  • Heat intolerance
  • Emotional weakness
  • Cold, clammy skin
  • Growth of the thyroid gland
Thyroid Problems and Pregnancy: Symptoms and Possible Consequences

The treatment of hyperthyroidism during pregnancy includes antithyroid medication. This medication works to normalize hormone levels, both for mother and for baby.

If hyperthyroidism is left untreated, it may cause miscarriage, fetal tachycardia, low birth weight, or fetal death.

Hypothyroidism can also be harmful to the mother. The most common consequences are:

  • Thyroid storm: A thyroid storm refers to the worsening of the symptoms of hypothyroidism. It is brought on by stress, serious infection, induced anesthesia, abstinence from antithyroid medication, or following iodine treatment.
  • Preeclampsia: Preeclampsia is a complication that produces a reduced circulation of blood to the mother’s organs. The affected organs include the kidneys, brain and also the placenta. Furthermore, preeclampsia places risk on the life of the unborn baby.

The early detection of these conditions is very important. Timely detection is the most effective way to prevent any complications. 

A family medical history of thyroid problems or unhealthy habits are factors you should take into consideration.

Normally, when a woman manifests the desire to become pregnant, or a thyroid problem is detected, her doctor will carry out a series of controls. This will include blood tests that measure her hormone levels.

“A family medical history of thyroid problems or unhealthy habits are factors you should take into consideration”

The consequences of an overactive or underactive thyroid during pregnancy can be very serious. However, there is no reason to worry, as hypothyroidism and hyperthyroidism are both easily diagnosed and perfectly treatable .


This text is provided for informational purposes only and does not replace consultation with a professional. If in doubt, consult your specialist.