Treatment of Hypothyroidism During Pregnancy

Hypothyroidism can cause problems for both the mother and the fetus during pregnancy. That's why it's important to know the treatment of hypothyroidism during pregnancy.
Treatment of Hypothyroidism During Pregnancy

Written by Edith Sánchez

Last update: 27 May, 2022

The treatment of hypothyroidism during pregnancy is basically the same as treatment for non-pregnant people. However, since the person is pregnant, there will be more follow-ups because it can lead to complications during a pregnancy.

Thyroid hormones play a very important role during a pregnancy. They affect both the development of the baby and the health of the mother. Fortunately, however, treatment of hypothyroidism will typically not lead to any major complications during pregnancy.

According to data, thyroid illnesses are most frequently diagnosed in women of reproductive ages. However, only an estimated 0.25% to 2.5% of pregnant women suffer from hypothyroidism. Therefore, it can be said that it is not a common problem during pregnancy.

The Thyroid and Hypothyroidism

the thyroid

The thyroid is a gland and its  main function is to secrete hormonal compounds. It’s an endocrine gland, so its hormones are secreted directly into the blood.

For proper functioning of the thyroid gland, the body needs iodine. Thyroid hormones have many functions, some of the most important being:

  • Growth and development of the body,
  • Increase the intake of oxygen,
  • Development of the central and peripheral nervous system,
  • Temperature regulation.

When the thyroid gland cannot produce a sufficient amount of the thyroid hormone, hypothyroidism occurs. This can cause anything from small annoyances to serious health issues.

In most cases, hypothyroidism can be easily treated without any complications, but it cannot be cured.

Changes in Thyroid Functioning During Pregnancy

Pregnancy causes not only physical changes in the body, but also hormonal changes that can affect the proper functioning of the thyroid. It is normal for the TSH (a stimulating hormone secreted by the thyroid) to be slightly lower during the first trimester of pregnancy.

The T3 (tiyodotironina) total and T4 (tiroxina) total will be higher throughout the whole pregnancy. In addition, the thyroid gland may even increase in size. In some cases, a goiter may appear, as well.

The fetus completely depends on the mother for the production of the thyroid hormone during the first 10 or 12 weeks. After that, the baby can produce this hormone for itself. However, the baby still depends on the mother to have sufficient iodine for the baby to adequately produce the hormone.

You may also be interested in: How to Minimize Hypothyroidism During Pregnancy

Treatment of Hypothyroidism During Pregnancy


Treatment for hypothyroidism when the patient is pregnant is necessary because it can pose risks for both the mother and the baby. Some of these risks are that the mother may develop anemia, myopathy, or congestive heart failure.

It’s also possible that it may cause abnormalities in the placenta that can result in the baby being born underweight or having a postpartum hemorrhage. Risks that can occur as a result of hypothyroidism are severe.

Moreover, the thyroid hormone is fundamental for the brain development of the baby. The medical and scientific fields have not been able to establish what exactly the developmental risks of hypothyroidism are, but it’s clear that it can result in abnormalities.

Hypothyroidism also increases the risk of miscarriage during the first trimester and increases the chances of a premature birth. In addition, it can increase blood pressure, which can lead to preeclampsia.

Hypothyroidism Treatment During Pregnancy

The treatment of hypothyroidism during pregnancy is not a cure, but it can completely control the illness. Basically, the treatment replaces the thyroid hormone with synthetic levothyroxine. This is exactly the same as the T4 that thyroids produce.

The only risk of the synthetic hormone is if the dosage is not the correct amount. If too little is taken, the hypothyroidism continues. If it is too much, the patient may develop hyperthyroidism. That’s why it’s necessary to control the dosage and continue going to frequent follow-ups.

Another factor of hypothyroidism treatment during pregnancy is that doctors will test the thyroid’s performance and functionality every 6 to 8 weeks. These tests will determine if there should be any change in the dosage of the levothyroxine.

It’s also very important to control the level of iodine in the mother’s system. It’s imperative that the synthesis of the thyroid hormones in the mother and the fetus are not altered. For this reason, the mother should maintain an iodine-rich diet.

All cited sources were thoroughly reviewed by our team to ensure their quality, reliability, currency, and validity. The bibliography of this article was considered reliable and of academic or scientific accuracy.

  • Barranco, M. C., López, A. A., Gallard, F. D., & Fernández, S. G. (2007). Tratamiento del Hipotiroidismo durante el Embarazo. Revista de Posgrado de la VIa Cátedra de Medicina, 171, 24-28.
  • Cano, F. D., & Paredes, A. (2009). Hipotiroidismo y embarazo : Diagnóstico y tratamiento. Rev Obs Ginecol – Hosp Santiago Oriente Dr. Luis Tisné Brousse.
  • Carolina Barranco, M., Alberto López, A., & Darío Gallard Dra Silvana Griselda Fernández, F. (2007). TRATAMIENTO DEL HIPOTIROIDISMO DURANTE EL EMBARAZO. Revista de Posgrado de La VIa Cátedra de Medicina.
  • Enfermedad tiroidea y gestación (actualizado julio 2013). (2015). Progresos de Obstetricia y Ginecologia.
  • INFARMED. (2014). Levotiroxina. Katalog BPS.
  • Pineda, J., Galofré, J. C., Toni, M., & Anda, E. (2016). Hipotiroidismo. Medicine (Spain).
  • Taylor, P. N., Minassian, C., Rehman, A., Iqbal, A., Draman, M. S., Hamilton, W., … Okosieme, O. E. (2014). TSH levels and risk of miscarriage in women on long-term levothyroxine: A community-based study. Journal of Clinical Endocrinology and Metabolism.
  • Soledad, H. V. (2013). Trastornos tiroideos en el embarazo. Revista Médica Clínica Las Condes.

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