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Thyroid During Pregnancy & Infancy

Even before conception, thyroid conditions that have lingered untreated can hinder a woman’s ability to become pregnant or can lead to miscarriage. Fortunately, most thyroid problems that affect pregnancy are easily treated. The difficulty lies in recognizing a thyroid problem during a time when some of the chief complaints — fatigue, constipation, and heat intolerance — can be either the normal side effects of pregnancy or signals that something is wrong with the thyroid.

Although detecting a thyroid problem is important, it is equally necessary for those already diagnosed with a condition to have the thyroid checked if they are planning to become pregnant or are pregnant.
Thyroid hormone is necessary for normal brain development. In early pregnancy, babies get thyroid hormone from their mothers. Later on as the baby’s thyroid develops it makes its own thyroid hormone. An adequate amount of iodine is needed to produce fetal and maternal thyroid hormone. The best way to ensure adequate amounts of iodine reach the unborn child is for the mother to take a prenatal vitamin with a sufficient amount of iodine. Not all prenatal vitamins contain iodine, so be sure to check labels properly.

Who Should Be Tested?

Despite the impact thyroid diseases can have on a mother and baby, whether to test every pregnant woman for them remains controversial. As it stands, doctors recommend that all women at high risk for thyroid disease or women who are experiencing symptoms should have a TSH and an estimate of free thyroxine blood tests and other thyroid blood tests if warranted. A woman is at a high risk if she has a history of thyroid disease or thyroid autoimmunity, a family history of thyroid disease, type 1 diabetes mellitus, or any other autoimmune condition. Anyone with these risk factors should be sure to tell their obstetrician or family physician. Ideally, women should be tested prior to becoming pregnant at prenatal counseling and as soon as they know they are pregnant.

Hypothyroidism & Pregnanacy

When a woman is pregnant, her body needs enough thyroid hormone to support a developing fetus and her own expanded metabolic needs. Healthy thyroid glands naturally meet increased thyroid hormone requirements. If someone has Hashimoto’s thyroiditis or an already overtaxed thyroid gland, thyroid hormone levels may decline further. So, women with an undetected mild thyroid problem may suddenly find themselves with pronounced symptoms of hypothyroidism after becoming pregnant.

Thyroid hormone is critical for the brain development of a fetus, because it depends solely on its mother for its thyroid hormone for most of the first trimester of pregnancy. When deprived of thyroid hormone, a baby is at an increased risk for abnormal brain development, which may lead to mental retardation.

Most women who develop hypothyroidism during pregnancy have mild disease and may experience only mild symptoms or sometimes no symptoms. However, having a mild, undiagnosed condition before becoming pregnant may worsen a woman’s condition. A range of signs and symptoms may be experienced, but it is important to be aware that these can be easily written off as normal features of pregnancy. Untreated hypothyroidism, even a mild version, may contribute to pregnancy complications. Treatment with sufficient amounts of thyroid hormone replacement significantly reduces the risk for developing pregnancy complications associated with hypothyroidism, such as premature birth, preeclampsia, miscarriage, postpartum hemorrhage, anemia, and abruptio placentae.

Treating Hypothyroidism during pregnancy

There is no difference between treating hypothyroidism when a woman is pregnant than when she isn’t. Levothyroxine sodium pills are completely safe for use during pregnancy. They will be prescribed in dosages that are aimed at replacing the thyroid hormone the thyroid isn’t making so that the TSH level is kept within normal ranges. Once it is consistently in the normal range, the doctor will check TSH levels every six weeks or so. The physician may also counsel patients to take their thyroid hormone pills at least one-half hour to one hour before or at least four hours after eating or taking iron-containing prenatal vitamins and calcium supplements, which can interfere with the absorption of thyroid hormone.

More about Hypothyroidism during pregnancy

Graves’ disease tends to strike women during their reproductive years, so it should come as no surprise that it occasionally occurs in pregnant women. Reports on pregnancies lasting longer than twenty weeks suggest that Graves’ disease occurs in 2 per 1,000 pregnancies or 0.2 percent of all pregnancies. Pregnancy may worsen a preexisting case of Graves’ disease. Graves’ disease can also emerge for the first time, typically during the first trimester of pregnancy. The disease is usually at its worst during the first trimester. It tends to then improve in the second and third trimesters and flare up again after delivery.