Medically reviewed by
Natalie Bessom, D.O. Board-certified family medicine doctor with specialty training in nutrition, USA
Learn why the early diagnosis of hypothyroidism in pregnancy is critical, the risks of hypothyroidism in pregnancy, and how do doctors treat hypothyroidism in pregnancy.
This article examines:
- What are the common causes of hypothyroidism in pregnancy?
- What are the risks of hypothyroidism to the baby?
- How do doctors treat hypothyroidism during pregnancy?
- What is post-partum thyroiditis?
Hypothyroidism is an underactive thyroid gland whereby the thyroid gland does not produce enough thyroid hormones to keep the body functioning normally. When your body is not able to produce enough thyroid hormones, it, in turn, affects many different systems within the body.
In order to cope with the physical changes and demands during pregnancy, the thyroid often goes through noticeable changes. However, an undiagnosed thyroid problem may put mothers at risk of having issues when trying to conceive and during pregnancy. These problems can include miscarriages, infertility, and menstruation issues.
What are the common causes and symptoms of hypothyroidism in pregnancy?
The most common cause of hypothyroidism is Hashimoto’s thyroiditis. Hashimoto’s thyroiditis is an autoimmune disease where the body attacks its own healthy thyroid cells. It is the most common cause of hypothyroidism in the United States.
Hypothyroidism affects between 3-5% of all pregnant women and often goes undiagnosed due to mild or nonexistent symptoms. Because symptoms of hypothyroidism are similar to pregnancy symptoms, it often goes undetected.
Common symptoms of hypothyroidism include:
- Thinning of hair
- Weight gain
- Brain Fog
- Dry or rough skin
- Aches and pains of muscles
What are the risks of hypothyroidism to the baby?
Throughout pregnancy, the thyroid hormone is critical for the brain development of the baby. The thyroid hormone supports not only brain development but overall growth as well. Mothers who have been diagnosed with hypothyroidism should have their thyroid health and levels checked as soon as the pregnancy is confirmed.
Severe undiagnosed hypothyroidism in the mother may lead to:
- Impaired brain development of the baby
- Premature birth
- Low birth weight
- Respiratory problems in the newborn
Recent studies have shown that mild developmental brain abnormalities may be present in babies born to women with undiagnosed hypothyroidism.
Iodine is a vital and necessary nutrient for the production of thyroid hormones and for human development. Studies have concluded that severe iodine deficiency during pregnancy can lead to major and irreversible effects such as:
- Increased risk of pregnancy loss
- Neonatal hypothyroidism
- Cretinism (a congenital condition marked by physical stunting and intellectual disability caused by severe hypothyroidism)
How do doctors treat hypothyroidism during pregnancy?
The main goal for treating hypothyroidism during pregnancy is to ensure that there is an adequate replacement of thyroid hormones for the health of mother and child.
During pregnancy, the most notable change is the increase of thyroxine-binding globulin (TBG) levels. TBG is a protein that helps move and deliver thyroid hormones throughout the body. This increase is due to the elevated levels of estrogen during pregnancy that help the body:
- Develop the baby
- Develop the uterus
- Develop the placenta
- Transfer nutrients
Thyroid hormone levels change during pregnancy, therefore, medication and dosage can change as well. Thyroid function tests should be performed every 4 weeks during the first half of pregnancy.
Levothyroxine is a thyroid hormone-replacing drug that is most commonly prescribed to pregnant women. Due to the rise in TBG levels, a higher dosage may be required. It is important to note that the American Thyroid Association recommends that thyroid hormone replacement drugs should not be taken at the same time as prenatal vitamins. This is because prenatal vitamins contain iron and calcium and can interfere with the absorption of the medication.
Pregnant women should always consult and follow the advice of their healthcare provider in order to minimize risks and complications.
What is postpartum thyroiditis?
Postpartum thyroiditis is the inflammation of the thyroid gland that occurs after pregnancy. It occurs during the 1st year of postpartum and affects 5% of women. Women are at greater risk of developing postpartum thyroiditis if they:
- Suffer from an autoimmune disorder
- Have positive antithyroid antibodies
- Have a history of thyroid disfunction
- Have a history of postpartum thyroiditis (20% of women will develop the recurrence of thyroiditis with additional pregnancies)
- Possess a family history of thyroid dysfunction or diseases
Mothers who are aware of these conditions or experience symptoms postpartum should consult their healthcare provider immediately.
- The thyroid undergoes notable changes due to the demands of pregnancy
- Symptoms of hypothyroidism are similar to pregnancy symptoms, and therefore, often goes undetected
- It is important to check thyroid hormone and health as soon as the pregnancy is known
- The thyroid hormone is critical for the brain development of the baby
- Mild developmental brain abnormalities may be present in babies born to women with undiagnosed hypothyroidism
- TBG levels increase during pregnancy due to the rise of estrogen levels
- Levothyroxine is a thyroid hormone-replacing drug that is most commonly prescribed to pregnant women
- Postpartum thyroiditis is the inflammation of the thyroid gland that occurs after pregnancy and affects 5% of women
- Early detection of a thyroid condition during pregnancy is critical
Managing new medication, additional supplements, weight changes, and blood work can be overwhelming. If you want to get a head start and better manage these changes download our ThyForLife app. ThyForLife is an all-in-one- thyroid solution at your fingertips.
Here at ThyForLife, we do our utmost to provide accurate information. If you require more detailed information regarding medical terms, conditions, and practices please consult your healthcare professional. Always listen to the advice of your healthcare provider.