Screening for thyroid disorders during pregnancy: Results of a survey in Maine

Objective Guidelines regarding prenatal screening for thyroid deficiency are conflicting, and current practice in primary care settings is unknown. Our survey sought to determine the: 1) extent of screening in Maine; 2) factors associated with screening; and 3) laboratory cut-off levels used. Study design In 2004 we surveyed 61 prenatal care practices, representing 246 practitioners and 85% of Maine deliveries. Results Screening via thyroid-stimulating hormone (TSH) testing was routine in 48% of the practices. Obstetrician practices screened at a significantly higher rate than family practices (56% vs 8%; odds ratio [OR] 15.0, 95% CI 1.9-130.0). Nonsignificant higher rates were found for urban versus rural, and multipractitioner versus solo practices. The lower TSH cut-off levels ranged between 0.1 and 0.5 mU/L among practices; the upper cut-off levels ranged between 3.5 and 5.5 mU/L. Conclusion Prenatal screening for thyroid deficiency varies among practices, reflecting conflicting guidelines. TSH cut-offs are also variable and might benefit from standardization.