Ultrasonography of the thyroid during pregnancy

To discover whether pregnancy causes ultrasonically detectable changes in the thyroid, an ultrasound examination of the thyroid was performed repeatedly in 21 pregnant women with no history of thyroid disease. Seven patients were examined three times and 14 twice during the course of pregnancy. The size of the thyroid was estimated and the echogenicity assessed with respect to homogenicity and degree by comparison with the echogenicity of adjacent muscles. The results were compared with the results of a control group of healthy female volunteers. The mean volume of the thyroid increased slightly during the course of pregnancy. No changes in the echogenicity or echostructure were noted.