“Women of reproductive age can have difficulties conceiving,” Dr. Yoram Shenker from the University of Wisconsin School of Medicine and Public Health, who specializes in endocrinology, says. If hormone levels are too low, a woman may not be ovulating as she should. Up to 5 percent of women who have trouble getting pregnant turn out to have a hypothyroidism. Newborns are screened for congenital hypothyroidism. “It’s not common but it’s important to diagnose,” Dr. Shenker says. “Otherwise kids can suffer from low IQ.”