Various reports indicate that the incidence of con-genital hypothyroidism is increasing in developednations, and that improved detection and more inclu-sive criteria for the disease do not explain this trendentirely. One risk factor documented in numerousstudies is exposure to radioactive iodine found in nu-clear weapons test fallout and nuclear reactor emis-sions. Large amounts of fallout disseminated world-wide from the meltdowns in four reactors at the Fu-kushima-Dai-ichi plant in Japan beginning March 11,2011 included radioiodine isotopes. Just days afterthe meltdowns, I-131 concentrations in US precipita-tion was measured up to 211 times above normal.Highest levels of I-131 and airborne gross beta weredocumented in the five US States on the Pacific Ocean. The number of congenital hypothyroid cases in thesefive states from March 17-December 31, 2011 was16% greater than for the same period in 2010, com-pared to a 3% decline in 36 other US States (p <0.03). The greatest divergence in these two groups (+28%)occurred in the period March 17-June 30 (p <0.04).Further analysis, in the US and in other nations, isneeded to better understand any association betweeniodine exposure from Fukushima-Dai-ichi and con-genital hypothyroidism risk.<\/p>\n