1 Department of Obstetrics, Gynecology, and Reproductive Sciences, Yale School of Medicine, 333 Cedar Street, P.O. Box 208063, New Haven, CT 06520-8063. Electronic address: Christian.pettker@yale.edu.
2 Department of Neonatology, Beth Israel Deaconess Medical Center, 330 Brookline Ave, Boston, MA 02215.