The NBDPS was a national study to discover clues about what causes birth defects.
The study was being conducted in 10 states across the U.S.
There were two parts to the study: a telephone interview and cheek cell collection.
The NBDPS study collected data on births from 1997 to 2011, although researchers continue to analyze the rich source of information on birth defects.
Over 35,000 women participated in the study.
Answers from the phone interview and results of genetic tests are confidential. Your identity will remain private.
The study was funded by the Centers for Disease Control and Prevention (CDC).
