Hypothyroidism: Should we screen all pregnant women?

What are the practical implications of recent studies linking maternal thyroid deficiency with impaired growth, adverse neurologic outcomes, and fetal death?

Dr. Blazer is director, neonatal unit, and Dr. Zimmer is director, obstetrics unit, Rambam Medical Center and Faculty of Medicine, Technion-Israel Institute of Technology, Haifa, Israel.

Emerging research indicates that thyroid hormones play a key role in fetal brain development, and asymptomatic hypothyroidism during pregnancy may have an adverse effect on fetal growth and neurologic development. Findings published in the past year call our attention to the importance of identifying and adequately treating thyroid-deficient gravidas:

But given the paucity of data on how maternal hypothyroidism affects the offspring, is universal screening justified? We review the evidence to date, present the current positions of 3 organizations, and offer recommendations for current clinical practice.