Subclinical thyroid disease linked to preterm delivery: screen women for thyroid disease if they deliver before 32 weeks' gestation.(News)

VANCOUVER, B. C. -- Subclinical thyroid disease constitutes a novel risk factor for very early preterm delivery. Alex Stagnaro-Green, M.D., said at the annual meeting of the American Thyroid Association.

Based upon new findings from the prospective case-control Camden Study, all women with a history of very early preterm delivery (PTD)--that is, delivery before completing 32 weeks' gestation--should be screened for thyroid disease, according to Dr. Stagnaro-Green, professor of medicine at the New Jersey Medical School, Newark.

The Camden Study is an ongoing investigation looking primarily at the relationship between nutritional factors and pregnancy outcome in a cohort of low-income New Jersey women free of preexisting disease.

Given the growing evidence during the last 15 years demonstrating increased risk of spontaneous abortion in women who have an underactive thyroid or thyroid antibodies, Dr. Stagnaro-Green and his coinvestigators sought to determine whether the incidence of these thyroid abnormalities was also increased in Camden Study participants with PTD.

Of the 953 women in the study who have given birth to date, 124 had PTD, including 28 with very early PTD. These 124 cases were matched to 124 randomly selected controls drawn from the pool of Camden Study participants with term delivery.

Thyroid function testing was performed in all study participants at the first prenatal visit at a mean of 15.5 weeks' gestation. The prevalence of subclinical hypothyroidism as defined by a TSH level of at least 3 mU/L was 14.3% among women who subsequently had a very early PTD, compared with 5.5% in women with term delivery or PTD delivery at 32-37 weeks.

Eighteen percent of women who would go on to very early PTD had ...