According to the study findings, even moderate thyroid dysfunction during early pregnancy can significantly increase the risk of serious complications, emphasizing the recommendation for universal first trimester screening.
Currently, a "case-finding" approach is the standard practice, and women are screened for thyroid issues only if there are clinical signs and symptoms and the physician suspects a thyroid condition, so this recommend represents a departure from the current practice.
The study, which was funded and conducted by Christian Medical College and Hospital in Punjab India, found that even mild thyroid dysfunction -- which would not otherwise be diagnosed as "hypothyroidism" -- could greatly increase the risk of serious problems.
In particular, women who had mild dysfunction had -- compared to pregnant women with normal thyroid function --
- double the risk of miscarriage, premature labor, and low birth weight
- seven times greater risk of stillbirth
In this study, 1,000 pregnant women in their first trimester of pregnancy had their thyroid function evaluated. Normal thyroid function was identified in 533 patients, and 263 had mild dysfunction. The remaining patients were diagnosed with hypothyroidism and were withdrawn from the study so they could be treated for the hypothyroidism. The study followed up on the subjects until the end of pregnancy.
The study looked at rates of miscarriage, stillbirth, premature labor, and low birth weight, and found these risk factors were all greater in women with mild thyroid dysfunction.
"Our conclusions are that all pregnant women need to be screened for thyroid dysfunction at their first visit," said Dr. Jacob. "This should form the basis for the national societies to make a change in their guidelines."
Source: Endocrine Society - Endo 2012