Simple Blood Tests
Thyroid disorders are easily detected by a couple of simple blood tests that measure levels of the thyroid hormones T4 (thyroxine) and TSH (thyroid stimulating hormone). TSH works like a thermostat; it’s produced by the pituitary gland to regulate thyroid function. Levels of this hormone may also become too high or too low, as the pituitary gland attempts to compensate for an over- or underactive gland. Together, these blood test results let doctors know whether the thyroid is functioning normally or not.
There’s also a blood test that checks for the presence of anti-thyroid antibodies. High levels of these antibodies are typical of a thyroid disease called Hashimoto’s Thyroiditis (Mary Shomon’s eventual diagnosis), which always results in hypothyroidism. Hashimoto’s Thyroiditis is classified as an autoimmune disease, because the body has essentially turned against itself, forming antibodies that attack the cells in the thyroid and slow down production of thyroid hormone. The gland itself may compensate by becoming enlarged.
Planning for Pregnancy When You Have a Thyroid Disorder
If your thyroid is underactive, your doctor will prescribe some form of a synthetic version of the T4 hormone. Your body will respond to it the same way it would to the real thing. While establishing the correct dose can be quite easy in some individuals, others will fluctuate up and down before stabilizing. Once you go get pregnant, your doctor should do blood tests every month or two, then at least yearly once you’re stabilized.
With hyperthyroidism, or overactivity, some treatments are designed to slow down the thyroid’s secretion of hormones. This can be done with anti-thyroid drugs, or with radioactive iodine that essentially kills part of the gland to slow down its hormone production. Radioactive iodine cannot be used in women who are already pregnant, however, and Dr. Dominguez stresses there should be a six-month waiting period after treatment before attempting to conceive.
Normal laboratory TSH ranges are generally considered to be .3 to 5.5. For women who are already managing a thyroid disorder, experts generally agree that preconception planning is a must, and that medication should be adjusted until TSH levels are between 1 and 2 before a woman gets pregnant. During pregnancy, an endocrinologist or an obstetrician that’s familiar with thyroid issues should monitor blood levels closely.
Among the various threats to fertility, thyroid disorders are arguably the easiest to identify and treat. With a little extra attention on the part of your doctor, women with thyroid disorders—whether too slow or too fast—are very likely to have problem-free conceptions, normal pregnancies, and healthy babies.
A version of this article originally appeared in the Fall 2006 issue of Conceive Magazine.
Related Topics: Fertility Hormones; Fertility Threats; Thyroid and Infertility
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