Hidden thyroid problem during pregnancy?

Q: I’m pregnant and I’ve heard you can have a dangerous thyroid condition and not even know it.  What should I know?

A: Gestational hypothyroidism, or underactive thyroid during pregnancy, is a serious issue. Research suggests that an underactive thyroid during pregnancy can cause a range of medical complications for women and their babies. For mothers, these include miscarriage and diabetes in pregnancy. For infants, the condition is associated with low-birth weight and potentially lower IQ.

Gestational hypothyroidism may not show symptoms, so testing is vital. A recent study by researchers at the medical laboratory company Quest Diagnostics found that as many as 15% of pregnant women may have the disorder. Pregnant women ages 35 to 40, Asian women and those who weigh over 275 pounds are among the most likely to be at risk. 

The good news is that a simple blood test to determine TSH (thyroid-stimulating hormone) levels can tell you if you have an underactive thyroid. New medical guidelines recommend TSH testing for certain women, particularly those with a family or personal history of thyroid disease or prior pregnancy problems, like miscarriages. Women 30 years of age or older should also get tested, even if they don’t have any other risk factors. Your physician may prescribe oral therapies if you have the disorder. 

If you have gestational hypothyroidism it is important to follow up with your doctor after you deliver your baby to make sure you don’t have ongoing thyroid problems. Symptoms of postpartum hypothyroidism can range from fatigue and depression to irritability and weight gain. If you are concerned, talk to your doctor.

Harvey W. Kaufman, M.D., senior medical director, Quest Diagnostics