1. Section of Maternal-Fetal Medicine, Department of Obstetrics and Gynecology, University of Chicago, Chicago, Illinois; Department of Obstetrics and Gynecology (MC2050), University of Chicago, 5841 S. Maryland Avenue, Chicago, IL 60637
2. Section of Maternal-Fetal Medicine, Department of Obstetrics and Gynecology, University of Chicago, Chicago, Illinois