Oct. 11 (HealthDay News) -- Routine thyroid screening is not recommended for pregnant women, according to the top group representing U.S. obstetricians/gynecologists.

The American College of Obstetricians and Gynecologists (ACOG) Committee Opinion is published in the October issue of Obstetrics & Gynecology.

The thyroid is a small gland in the neck that controls important body functions such as heart rate, body temperature, blood pressure and energy level. When the thyroid produces too little hormone, it creates a condition called hypothyroidism.

The ACOG committee recommendation was made in response to a debate over whether all pregnant women should be screened for asymptomatic (subclinical) hypothyroid disease, which affects about 2 percent to 5 percent of women. Some studies have suggested a relationship between subclinical hypothyroidism in pregnant women and preterm delivery and impaired brain development in children.

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, 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."

Thyroid testing for pregnant women should be limited to those with symptoms or history of thyroid disease or other medical conditions associated with it, such as diabetes, according to the ACOG.

SOURCE: American College of Obstetricians and Gynecologists, news release, Oct. 1, 2007