New York Times Examines Debate Over Thyroid Testing For Pregnant Women

Main Category: Pregnancy / Obstetrics
Also Included In: Endocrinology;  Women's Health / Gynecology
Article Date: 16 Apr 2009 - 5:00 PDT

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The New York Times on Tuesday examined the debate among obstetricians over whether to test pregnant women for thyroid conditions, which can lead to complications during pregnancy. The thyroid gland, which is located in the neck, produces hormones that control the body's metabolism and assist in regulating body weight, heart rate and other factors. The under- or over-production of these hormones -- known as hypothyroidism and hyperthyroidism, respectively -- during pregnancy can result in complications like miscarriage, premature birth, preeclampsia or impaired intelligence in the child. The Times reports that medical societies currently recommend testing only high-risk women for thyroid conditions. However, because the symptoms of thyroid problems can be subtle and easily confused with other pregnancy-related conditions, the risks associated with such problems have led some obstetricians and endocrinologists to consider whether all pregnant women and women who are trying to conceive should receive a blood test to check thyroid-stimulating hormone -- or T.S.H. -- which prompts the gland's hormone production.

The Times reports that hypothyroidism is the "more frequent and worrisome concern," with about 10% to 20% of reproductive age women testing positive for the antibodies known to attack and destroy the thyroid, the Times reports. These women have almost twice the risk of miscarriage. The most common thyroid condition is subclinical hypothyroidism, a mild and common form of thyroid deficiency that occurs when the thyroid hormone T4 is normal but T.S.H. is slightly higher. The condition often is left undiagnosed if no obvious symptoms are present and affects 2% to 3% of women. According to the Times, about a decade ago, the American Association of Clinical Endocrinologists endorsed routine T.S.H. testing in all women considering pregnancy.

However, most doctors' groups -- including the American College of Obstetricians and Gynecologists -- do not endorse universal prenatal thyroid screening, citing doubts about whether such testing would provide enough health benefits to justify the cost of testing almost 6.4 million pregnant women annually and educating doctors to interpret the results of the test. Most medical societies endorse selective screening for women considered at high-risk due to family history of thyroid conditions -- such as Type 1 diabetes or autoimmune disease -- or previous miscarriages, premature delivery, and symptoms of goiter or sluggish thyroid. However, recent research has "revealed flaws in that strategy," the Times reports. A British study found that screening only women with such criteria missed 30% of those with hypothyroidism and 69% with hyperthyroidism. Alex Stagnaro-Green, an endocrinologist at Touro University's College of Medicine, said the "problem is, it's not good enough," adding that he believes that in the future "data will be forthcoming that will push us towards universal screening."

According to the Times, the "big unanswered question" is whether women with subclinical hypothyroidism could benefit from treatment. Studies have suggested the T4-replacement therapy is protective, but there have not been enough large clinical trials to test such treatments in mildly thyroid-deficient women. Catherine Spong, chief of pregnancy and perinatology at the National Institute of Child Health and Human Development, said that pregnancy is such a crucial time for development that "to expose a baby to a medication without known benefit may not be the best thing, unless we truly know that it's helpful" (Chen, New York Times, 4/14).

Reprinted with kind permission from http://www.nationalpartnership.org. You can view the entire Daily Women's Health Policy Report, search the archives, or sign up for email delivery here. The Daily Women's Health Policy Report is a free service of the National Partnership for Women & Families, published by The Advisory Board Company.

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