For the purposes of the study, hypothyroidism in a pregnant woman was defined as having a TSH of 2.5 or higher, along with positive thyroid peroxidase (TPO) antibodies. Hyperthyroidism was defined as undetectable TSH concentration and elevated Free T4.
The research found that the "case finding" approach -- where patients are identified as hypothyroid or hyperthyroid based on symptoms -- leaves the majority of pregnant women with thyroid disease undiagnosed, as compared to universal screening, which would test all pregnant women.
The researchers found that compared to universal screening, case-finding carries a greater risk of thyroid-related adverse outcomes in pregnancy, including miscarriage, high blood pressure, preeclampsia, gestational diabetes, premature delivery, and low birthweight infants.
According to the researchers: "...treatment of identified thyroid hormonal abnormalities during pregnancy results in a significant decrease in adverse outcomes. Our study confirms that case finding fails to detect the majority of pregnant women with thyroid disease. A comprehensive cost-effectiveness analysis is required to resolve the debate of universal screening for thyroid disease in pregnancy."
What Should You Do?
The researchers and doctors will continue to debate whether or not universal thyroid screening is cost-effective, and whether or not it is cost effective to protect the health of mothers and babies with thyroid testing. While they continue debating, the critical message is this: if you are newly pregnant, insist on thyroid tests, including, at minimum, the TSH, Free T4, and thyroid antibodies blood tests.
If you'd like to view a short video on the subject, see Doctor's TVC for a 2-minute summary.
More Information on Pregnancy and Thyroid Disease
- Thyroid Disease & Pregnancy Information Center
- Managing Thyroid Disease During and After Pregnancy: Guidelines
Source: Negro, Roberto, Alan Schwartz, Riccardo Gismondi, Andrea Tinelli, Tiziana Mangieri, and Alex Stagnaro-Green. "Universal Screening Versus Case Finding for Detection and Treatment of Thyroid Hormonal Dysfunction During Pregnancy." Journal of Clinical Endocrinology and Metabolism, published February 3, 2010 online Rapid Publication