Elevated arsenic concentrations have been detected in the drinking water of a number of countries including Argentina, Chile, China, Mongolia, India, Mexico, Taiwan, Thailand, Viet Nam, parts of the United States, and Australia. However, Bangladesh has been the most affected. An estimated 133 million Bangladeshis are at risk of drinking arsenic contaminated drinking water, leading the World Health Organization to call this the largest mass poisoning of a population in history. One environmental survey reported that 56% of the water samples tested had arsenic concentrations exceeded the World Health Organization drinking water guideline of 10 g/L and 37% exceeded the Bangladesh (and current US) drinking water standard of 50 g/L. Population-based epidemiologic studies have linked chronic exposure to elevated arsenic concentrations with skin lesions, skin cancer, internal organ cancers, neurological effects, hypertension, cardiovascular disease, pulmonary disease, peripheral vascular disease, and diabetes mellitus. These studies relied primarily upon biomarkers such as stable, elevated urinary arsenic concentrations or arsenic concentrations in toenails to determine if an individual had been exposed to arsenic-contaminated drinking water. However, there have not been studies that have investigated the effects of chronic arsenic exposure on birth outcomes using biomarkers of both exposure and effect at a wide range of drinking water arsenic exposure. Moreover, studies to date have not incorporated multiple pathway biomarkers (eg., exposure, genomic, proteomic) in an integrated study.