We used data from CDC's National Birth Defect Prevention Study, the largest case-control study of birth defects ever conducted. Data were collected for cases and controls via a computer-assisted telephone information, and included information related to demographics, pre-existing health conditions, medication use, employment/occupation, personal hobbies, diet, and water use. This dataset is not publicly accessible because: EPA cannot release personally identifiable information regarding living individuals, according to the Privacy Act and the Freedom of Information Act (FOIA). This dataset contains information about human research subjects. Because there is potential to identify individual participants and disclose personal information, either alone or in combination with other datasets, individual level data are not appropriate to post for public access. Restricted access may be granted to authorized persons by contacting the party listed. It can be accessed through the following means: Data that CDC collects or holds must be available for data sharing within a year after the data are evaluated for quality and shared with any partners in data collection activity. Because NBDPS data contain PII, NBDPS data are not released publicly. Instead, they are available via a special use agreement. Qualified researchers can be granted access to NBDPS data for analysis through collaboration with one of the Centers for Birth Defects Research and Prevention. The procedure for applying for access to NBDPS data can be found on the NBDPS Public Access Procedures web site: https://www.cdc.gov/ncbddd/birthdefects/nbdps-public-access-procedures.html. Format: This research was conducted with data collected by the CDC-sponsored National Birth Defects Prevention Study (NBDPS). These data include birth data and geocoded residential addresses before and during pregnancy.

This dataset is associated with the following publication: Zaganjor, I., A. Keil, T. Luben, T. Desrosiers, L. Engel, J. Reefhuis, A. Michalski, P. Langlois, A. Olshan, and N.B.D.P.S. [Corporate Author]. Is maternal employment site a source of exposure misclassification in studies of environmental exposures and birth outcomes? A simulation-based bias analysis of haloacetic acids in tap water and hypospadias.. Environmental Epidemiology. Wolters Kluwer, Alphen aan den Rijn, NETHERLANDS, 6(2): e207, (2022).