Impact of pregnancy and other factors on the levels of urinary perchlorate, thiocyanate, and nitrate among females aged 15-44 years: data from National Health and Nutrition Examination Survey: 2003-2008.

Impact of pregnancy on levels of urinary perchlorate, thiocyanate, and nitrate has not been studied using large scale data. Data from National Health and Nutrition Examination Survey for the years 2003-2008 were used to evaluate risk factors that impact levels of these contaminants among females of child bearing age. In addition to pregnancy, other risk factors evaluated were: age, race/ethnicity, smoking status, serum triglyceride levels, and iodine deficiency status. Pregnancy did not affect the levels of perchlorate and nitrate but, new to this study, it was found that thiocyanate levels were statistically significantly lower among pregnant females as compared to non-pregnant females (p<0.01). Iodine deficient females had statistically significantly lower levels of these contaminates than iodine replete females (p<0.01). Levels of thiocyanate among smokers were about five times higher than among non-smokers. Non-Hispanic Blacks had the lowest and Mexican Americans had the highest levels of perchlorate and nitrate. The reverse was true for thiocyanate levels. There was an inverse association between nitrate and education levels. There was a positive association between serum triglyceride levels and the levels of these contaminants. Also, new to this study, of concern, was the fact that levels of these contaminants increased among females over the period 2005-2008. Levels of perchlorate, thiocyanate, and nitrate did not vary across pregnancy trimesters.