subject: How Pregnancy Affects The Thyroid Gland [print this page] A normal pregnancy causes substantial changes in the thyroid gland interfering with thyroid hormone production. Pregnancy places an increased pressure and demand on the thyroid gland.
In pregnancy, hormones and estrogen are produced at higher levels than normal. This will in turn cause an increase in the thyroid hormone levels in the blood. Estrogen on the other hand increases the production of thyroid-binding globulin the protein responsible for transportation of thyroid hormone in the blood.
These hormone changes and variations do make it thyroid function tests harder to interpret if due to pregnancy hormones or if there is a true thyroid disorder.
As thyroid hormones are critical in babys brain and nervous system development, pregnant women need more iodine. They need at least 250 mcg per day as there is not enough iodine in prenatal vitamins.
In persons without previous thyroid problems, pregnancy may or may not result in a full blown thyroid disease. But in persons with previous thyroid problems, this extra demand of pregnancy on the thyroid gland may cause a more serious clinical disease and will need extra care by the physician.
Hyperthyroidism in Pregnancy
Hyperthyroidism diagnosis in pregnancy can be quite difficult as there are alterations in the hormones commonly used for diagnosis. The symptoms are just the same with a person who has hyperthyroidism but is not pregnant. There will be fatigue and hair falling out. In pregnant persons, normal pregnancy weight gain will be more difficult.
The most common result of hyperthyroidism in pregnancy is Graves disease. It is an autoimmune disease that causes too much production of thyroid hormones.
Here are some of the consequences related to hyperthyroidism in pregnancy:
Hyperemesis gravidarum severe nausea and vomiting
Miscarriage or spontaneous abortion
Preterm labor/Premature birth
Low birth weight babies
Stillbirths
Preeclampsia
Congestive heart failure
Thyroid storm
Mild cases do not require treatment. However, more severe cases might need treatment with propylthiouracil or methimazole.
The most common cause of hypothyroidism in pregnancy is Hashimotos disease. Similar with Graves disease, Hashimotos thyroiditis alters the hormone production.
Hypothyroidism in pregnancy could be due to an existing undiagnosed thyroid disorder or hyperthyroidism treatment resulting in prior treatment of removal of the thyroid gland. Symptoms could be extreme fatigue, muscle cramps, constipation, and memory problems.
Here are some of the consequences related to hypothyroidism in pregnancy:
Congestive heart failure
Preeclampsia
Miscarriage
Low birth weight
Stillbirths
Anemia
Hypothyroidism treatment in pregnancy is usually through intake of a synthetic thyroxine. Thyroid medications are known to be safe for use during pregnancy.
