Routine Thyroid Tests Not Recommended in Pregnant Women

Routine thyroid screening is not recommended for pregnant women.

Interest in thyroid disease in pregnancy, especially subclinical hypothyroidism, has increased because of reports suggesting that various types of thyroid deficiency during pregnancy result in impaired neurodevelopment in offspring. Other reports associate subclinical hypothyroidism with preterm delivery. These findings have led some societies and groups to recommend routine thyroid screening during pregnancy.

However, data indicating fetal benefit from thyroxine supplementation in pregnant women with subclinical hypothyroidism currently are not available. Based on current literature, thyroid testing in pregnancy should be performed on symptomatic women and those with a personal history of thyroid disease or other medical conditions associated with thyroid disease (e.g., diabetes mellitus). Without evidence that identification and treatment of pregnant women with subclinical hypothyroidism improves maternal or infant outcomes, routine screening for subclinical hypothyroidism currently is not recommended. This is the conclusion of The American College of Obstetricians and Gynecologists (ACOG; Washington, DC, USA) Committee, which was published in the October 2007 issue of the journal Obstetrics and Gynecology.

It is known that untreated symptomatic hypothyroidism can lead to preeclampsia or placental abruption (where the placenta separates from the uterine wall) in women, and preterm birth, low birth weight, and decreased mental ability in infants. However, the ACOG finds there is no evidence that identifying and treating women with subclinical hypothyroidism improves outcomes for either mother or infant.

"This issue has been whether thyroid screening should be a routine test during prenatal care,” Dr. Sarah J. Kilpatrick, chairwoman of ACOG's Committee on Obstetric Practice, said in a prepared statement. "Some groups argue that identifying and treating asymptomatic hypothyroidism [subclinical hypothyroidism] will improve outcomes for pregnant women and their infants. With the information we have at this time, there isn't any proven health benefit.”

According to criteria established by the U.S. Preventive Services Task Force (Rockville, MD, USA), before recommending screening of asymptomatic individuals, there must be demonstrated improvement in important health outcomes of those individuals identified through screening.


Related Links:
U.S. Preventive Services Task Force
The American College of Obstetricians and Gynecologists