Levothyroxine in Women with Thyroid Peroxidase Antibodies before Conception

To the Editor: In their randomized trial involving euthyroid women who were positive for thyroid peroxidase antibodies before conception, Dhillon-Smith et al. (April 4 issue) 1 did not find higher risks of pregnancy loss or other adverse outcomes among women who did not receive levothyroxine than among those who did receive the drug. I am concerned, however, that an important finding that is mentioned only briefly in Results may be overlooked by readers. The authors reported that abnormal results on thyroid-function tests developed in nearly 10% of the women in the levothyroxine group and in the placebo group, either before or . . .