Understanding Hypothyroidism & Pregnancy
Some women may already have hypothyroidism when they become pregnant. But others develop hypothyroidism during pregnancy.
The number one cause of hypothyroidism during pregnancy is Hashimoto's disease, an autoimmune disorder that causes the thyroid to become inflamed and unable to produce thyroid hormones. Other causes of hypothyroidism in pregnancy include existing hypothyroidism that hasn’t been treated properly, previous injury to the thyroid, removal of the thyroid to treat hyperthyroidism, and changes in reproductive hormones.
Effects on mother and baby
If hypothyroidism isn't diagnosed and treated properly during pregnancy, it could lead to serious complications, including preeclampsia in the mother, miscarriage, low birth weight and even stillbirth.
A mother's hypothyroidism may have a negative effect on fetal growth and development. Always notify your doctor if you are pregnant or intend to become pregnant.
Hypothyroidism symptoms during pregnancy can be similar to symptoms experienced by people who are not pregnant. Symptoms can include extreme fatigue, muscle cramping, constipation, intolerance to cold, and problems with concentration or memory. Since some of these symptoms can be normal, pregnancy-related issues, doctors will use other diagnostic measures – in addition to review of symptoms – to test for hypothyroidism during pregnancy.
Diagnosis and treatment
Doctors use the same methods for diagnosing hypothyroidism in pregnant women as they do in other individuals: medical history, review of symptoms, a simple blood test called the thyroid-stimulating hormone (TSH test), and possibly other laboratory tests. Learn more about the TSH test.
Hypothyroidism treatment for pregnant women basically is the same as treatment for other individuals – thyroid hormone replacement medication. However, if a woman had hypothyroidism before pregnancy, her pre-pregnancy dose may need to be increased. Doctors should check the pregnant woman's thyroid function every 6-8 weeks during pregnancy.
1. National Institute of Diabetes and Digestive and Kidney Diseases. National Endocrine and Metabolic Disease Information Service. Pregnancy and Thyroid Disease. Available at:
http://endocrine.niddk.nih.gov/pubs/pregnancy/#pregnancy. Accessed March 1, 2013.