1 Department of Obstetrics and Gynecology, University of California, Irvine School of Medicine, 3800 West Chapman Ave, Chapman Pavilion, Suite 3400, Orange, CA 92868; Division of Maternal Fetal, Medicine, Department of Obstetrics and Gynecology, University of Colorado, Anschutz Medical Campus, Aurora, CO; Colorado Fetal Care Center, Children's Hospital of Colorado, Aurora, CO. Electronic address: jsteller@hs.uci.edu.
2 Department of Obstetrics and Gynecology, University of California, Irvine School of Medicine, 3800 West Chapman Ave, Chapman Pavilion, Suite 3400, Orange, CA 92868; Division of Maternal Fetal, Medicine, Department of Obstetrics and Gynecology, University of Colorado, Anschutz Medical Campus, Aurora, CO; Colorado Fetal Care Center, Children's Hospital of Colorado, Aurora, CO.