1 Department of Obstetrics and Gynecology, Columbia University Irving Medical Center, New York, NY.
2 Division of Maternal-Fetal Medicine, Department of Obstetrics, Gynecology, and Reproductive Sciences, University of California San Francisco, San Francisco, CA.
3 University at Albany, State University of New York, Albany, NY.
4 Department of Obstetrics and Gynecology, Columbia University Irving Medical Center, New York, NY; New York State Psychiatric Institute, New York, NY.
5 Department of Anesthesiology, Columbia University, New York, NY.
6 Division of Maternal-Fetal Fetal Medicine, Department of Obstetrics and Gynecology, Columbia University Vagelos College of Physicians and Surgeons, Columbia University Irving Medical Center, 622 West 168 St., New York, NY 10032. Electronic address: amf2104@cumc.columbia.edu.