Therapy of Hypothyroidism — When Are Changes Needed?

In this issue of the Journal, Mandel and coworkers report that women with primary hypothyroidism who were receiving thyroxine therapy often needed a larger dose of thyroxine when they were pregnant.1 This conclusion was based on the authors' finding of increases in serum thyrotropin concentrations in these women. None of the women had any clinical manifestations of hypothyroidism, and most had serum free-thyroxine indexes within the normal range, although the values decreased in seven of the eight women in whom they were measured both before and during pregnancy. Because the authors have summarized very well what is known . . .