Prevalence of congenital hypothyroidism--current trends and future directions: workshop summary.

In response to published newborn-screening data that have shown an increase in the incidence (birth prevalence) rate of primary congenital hypothyroidism (CH) in the United States, a workshop was held in Atlanta, Georgia, on February 27 and 28, 2008, to examine this issue. Topics of the meeting included pathophysiology, medical management, and follow-up of CH; transient hypothyroidism (etiology, clinical implications, management, and changes in prevalence); risk factors for CH; laboratory approaches to newborn screening for CH; state-specific evaluations of trends in incidence rates of CH; and concluding discussions on future directions to resolve outstanding issues. Through presentations and discussion, gaps in knowledge were identified, such as the lack of consistent definitions for CH and transient hypothyroidism and the effects of preventable risk factors on incidence rates of CH. One outcome of the meeting was a series of accompanying articles that examined (1) trends in the incidence rates of CH in individual states and nationally, (2) effects of newborn-screening practices on CH-incidence rates, (3) the contribution of transient hypothyroidism to CH-incidence rates, and (4) future research directions. In this summary, we briefly touch on the topics of these articles and examine highlights of other presentations from the workshop that illuminated the secular trends in reported CH-incidence rates in the United States.