[1] Ctr Dis Control & Prevent, Natl Ctr Birth Defects & Dev Disabil, Atlanta, GA USA
[2] Oak Ridge Inst Sci & Educ, Oak Ridge, TN USA
[3] Duke Univ Hosp, Div Plast Maxillofacial & Oral Surg, Duke Cleft & Craniofacial Ctr, Durham, NC USA
[4] Childrens Hlth Ctr, Durham, NC USA
[5] Univ S Florida, Coll Publ Hlth, Dept Community & Family Hlth, Birth Defects Surveillance Program, Tampa, FL USA
[6] Florida Dept Hlth, Florida Birth Defects Registry, Bur Epidemiol, Div Dis Control & Hlth Protect, Tallahassee, FL USA