National Institutes of Health Clinical Center, 9000 Rockville Pike, Bethesda, Maryland, United States
Northwestern University Department of Preventive Medicine, Chicago, Illinois, United States
California Birth Defects Monitoring Program, Berkeley, California, United States
National Institutes of Health Clinical Center, Bethesda, Maryland, United States
Ahmadu Bello University Teaching Hospital, Kaduna, Nigeria
National Institutes of Health Clinical Center, 9000 Rockville Pike, Bethesda, Maryland, United States
National Institutes of Health Clinical Center, 9000 Rockville Pike, Bethesda, Maryland, United States
National Heart, Lung and Blood Institute (NHLBI), 9000 Rockville Pike, Bethesda, Maryland, United States
Mid-Atlantic Associates, Baltimore, Maryland, United States
Suburban Hospital, Bethesda, Maryland, United States