1. Division of Epidemiology, College of Public Health, The Ohio State University, Columbus, Ohio.
2. Center for Biobehavioral Health, The Research Institute at Nationwide Children's Hospital, Nationwide Children's Hospital, Columbus, Ohio.
3. The Department of Obstetrics and Gynecology, The Ohio State University, Columbus, Ohio.
4. Cincinnati Children's Center for Breastfeeding Medicine, Cincinnati Children's Medical Center, Cincinnati, Ohio.