1. Centers for Disease Control and Prevention Atlanta Georgia USA
2. Center for Women's Reproductive Health and Department of Obstetrics and Gynecology, Division of Maternal‐Fetal Medicine University of Alabama at Birmingham Birmingham Alabama USA
3. Department of Obstetrics and Gynecology University of Utah Health Sciences Center Salt Lake City Utah USA
4. Division of Child and Adolescent Health, Department of Pediatrics Columbia University Irving Medical Center New York New York USA
5. Department of Population and Family Health, Mailman School of Public Health Columbia University Irving Medical Center New York New York USA
6. New York‐Presbyterian Hospital New York New York USA
7. Abt Associates Rockville Maryland USA