The myth of goiter in pregnancy

A common belief is that pregnancy causes goiter. Forty-nine matched pairs each consisting of a pregnant and a nonpregnant woman were examined by means of a blind, multiple-observer design. In 22 pairs the pregnant woman had the larger thyroid, whereas in 20 pairs the opposite was true. In six pairs the thyroid glands were not palpable, and in one pair the thyroid glands were of equal size. Five pregnant and three nonpregnant women had clinically significant goiters. None of the differences was statistically significant. No significance appeared when the data were controlled for race, age, body weight, or family history of thyroid disease. Therefore, goiter in pregnancy should be considered to be a pathologic condition in an iodine-replete population.