Hypothyroidism in Pregnancy
Hypothyroidism in pregnancy is usually caused by Hashimoto’s disease. This is a condition of chronic inflammation of the thyroid gland.
Like Graves’ disease, Hashimoto’s disease is an autoimmune disorder. Here the immune system attacks the thyroid causing inflammation and interfering with its ability to produce thyroid hormones.
Effects of Hypothyroidism on Mother and Baby
Uncontrolled hypothyroidism during pregnancy can lead to:
- Anemia- Lowered red blood cells in the body, which prevents the body from getting enough oxygen.
- Low birth weight
Because thyroid hormones are crucial to fetal brain and nervous system development, uncontrolled hypothyroidism, especially during the first trimester, can affect the baby’s growth and brain development.
Diagnosing Hypothyroidism in Pregnancy
Like hyperthyroidism, hypothyroidism is diagnosed through a careful review of symptoms and measurement of TSH and T4 levels.
Symptoms of hypothyroidism in pregnancy include:
- Extreme fatigue
- Cold intolerance
- Muscle cramps
- Problems with memory or concentration
High levels of TSH and low levels of free T4 generally indicate hypothyroidism. Because of normal pregnancy-related changes in thyroid function, test results must be interpreted with caution.
The TSH test showing high levels of TSH and normal free T4 imply Sub Clinical Hypothyroidism. This is a mild form of hypothyroidism that has no apparent symptoms.
Treating Hypothyroidism in Pregnancy
Hypothyroidism is treated with synthetic thyroid hormone called thyroxine, a medication which is identical to the T4 made by the thyroid. Women with preexisting hypothyroidism will need to increase their pre-pregnancy dose of thyroxine to maintain normal thyroid function. Thyroid function should be checked every 6 to 8 weeks during pregnancy. Synthetic thyroxine is safe and necessary for the well-being of the fetus if the mother has hypothyroidism.
Because the thyroid uses iodine to make thyroid hormone, iodine is an important mineral for a mother during pregnancy. During pregnancy, the baby gets iodine from the mother’s diet. Choosing iodized salt over plain salt and prenatal vitamins containing iodine will ensure this need is met.
Read about guidelines for managing Hyperthyroidism during pregnancy.