1 Division of Maternal-Fetal Medicine, Department of Obstetrics, Gynecology, and Reproductive Sciences, University of California, San Francisco, 490 Illinois St., 10th floor, Box 0132, San Francisco, CA, 94143. Electronic address: christine.blauvelt@ucsf.edu.
2 Division of Maternal-Fetal Medicine, Department of Obstetrics, Gynecology, and Reproductive Sciences, University of California, San Francisco, 490 Illinois St., 10th floor, Box 0132, San Francisco, CA, 94143.
3 Division of Maternal-Fetal Medicine, Department of Obstetrics and Gynecology, Columbia University, New York, NY.
4 Division of Maternal-Fetal Medicine, Department of Obstetrics, Gynecology, and Reproductive Sciences, University of California, San Francisco, San Francisco, CA.