1 Teachers College, Columbia University, New York, NY.
2 Division of Maternal-Fetal Fetal Medicine Department of Obstetrics and Gynecology Vagelos College of Physicians and Surgeons Columbia University 622 West 168th St. New York, NY 10032. Electronic address: amf2104@cumc.columbia.edu.
3 Department of Obstetrics and Gynecology, Columbia University, 622 West 168th St., New York, NY 10032.
4 Department of Obstetrics and Gynecology, University of California San Francisco, San Francisco, CA.
5 Department of Obstetrics and Gynecology, Columbia University, New York, NY.