"Checkups during pregnancy tend to focus around the waist. But theres growing debate about which motherstobe should have a gland in their neck tested too.  Numerous studies since  have found that an underactive thyroid httpsmedicalxpress.comtagsthyroid can raise a womans risk of miscarriage premature birth or a lower IQ for her baby  even if its so mildly sluggish that she feels no symptoms. The problem While serious cases are treated with a hormone pill so far theres little evidence that treating the milder cases makes a difference. So guidelines about who should be tested vary widely. Now a peek at prenatal testing httpsmedicalxpress.comtagsprenataltesting from one of the countrys largest medical labs suggests that nearly a quarter of pregnant women httpsmedicalxpress.comtagspregnantwomen are getting the simple thyroid blood test httpsmedicalxpress.comtagsbloodtest regardless of whether they have symptoms. Researchers at Quest Diagnostics examined records for half a million pregnant women. Of those who got tested a higherthanexpected number   percent  had an underactive thyroid. Thats fivefold higher than some previous estimates httpsmedicalxpress.comtagsestimates partly because the way in which the condition is diagnosed has changed recently says the study published by the Journal of Clinical Endocrinology  Metabolism. The vast majority of those women were in the gray zone with milder cases where no one knows for sure if a diagnosis helps or wastes money on testing and thyroid medication. The finding adds pressure for science to settle this longrunning controversy. We still dont have perfect answers says Dr. Elizabeth Pearce a wellknown endocrinologist at Boston Medical Center where a recent survey found widespread prenatal thyroid testing. But if its my patient in my office or its me or my family member Im going to treat every time. Obstetricians seem more wary. There are studies on both sides of the fence says Dr. Dena Goffman of New Yorks Montefiore Medical Center which tests only women at high risk. If you dont know what to do with the results you probably shouldnt order the test she said. The unassuming thyroid  a small bow tieshaped gland nestled in the front of the neck  plays a big role in good health for everyone. It produces hormones that regulate metabolism and can affect almost every type of tissue in the body. About  million Americans are estimated to have a malfunctioning thyroid that if serious enough can contribute to heart disease bonethinning osteoporosis and infertility. An overactive thyroid called hyperthyroidism speeds up bodily functions causing such symptoms as weight loss nervousness anxiety and increased heart rate and vision problems. Much more common is an underactive thyroid called hypothyroidism. It slows body functions causing such problems as fatigue weight gain depression constipation and dry skin. It even can contribute to high cholesterol according to the National Institutes of Health. Thyroid problems increase with age but they affect far more women than men  and pregnancy httpsmedicalxpress.comtagspregnancy puts extra stress on the gland. Having enough thyroid hormones is important for fetal brain development especially during the first trimester when the fetus depends solely on the mother for them. The hormones also play a role in avoiding miscarriage or premature birth httpsmedicalxpress.comtagsprematurebirth. Mothers also may harbor immune system cells called antibodies that subtly attack the gland and likewise are linked to miscarriage and prematurity. Italian researchers found that treating those women lowered their risk of encountering this problem. There is broad agreement that women with overt hypothyroidism  a seriously underactive gland  should be treated most likely given a onceaday hormone pill long known to be safe in pregnancy. But it takes blood testing to diagnose overt disease because even those women dont always report the vague symptoms. Those  blood tests are sure to uncover women with mild hypothyroidism too the people in the socalled gray zone. Some research has raised questions about whether mild cases really pose a pregnancy risk and preliminary results from a large British study recently found no overall IQ benefit to the resulting children if their mothers had been treated. But the damage might already have been done by the time treatment began late in the first trimester notes Bostons Pearce. In the U.S. doctors are anxiously awaiting a similar National Institutes of Health study results arent expected until . Whats the advice until then The American College of Obstetricians and Gynecologists recommends testing only pregnant women who have thyroid symptoms have had previous thyroid problems or have similar autoimmune diseases such as Type  diabetes  those considered at risk for overt disease. The American Thyroid Association goes further. Last summer it advised also testing all pregnant women age  and older and those with enlarged thyroids previous pregnancy problems or those who are obese says Pearce who coauthored the guidelines. Most guidelines cite the lack of evidence for treating mild cases. The thyroid association does urge treatment if those women harbor the worrisome antibodies. A final tip Pregnant women should check that their prenatal vitamins contain iodine important for proper thyroid function Pearce says. Not all do. Most Americans get enough iodine from dairy products bread seafood and iodized table salt. But women httpsmedicalxpress.comtagswomen need extra during pregnancy.    Explore further BMC conducts high rates of thyroid testing in pregnant women study finds httpsmedicalxpress.comnewsbmchighthyroidpregnantwomen.html"