[1] Johns Hopkins Univ, Sch Med, Dept Gynecol & Obstet, Div Maternal Fetal Med, Phipps 228 GYN OB,600 North Wolfe St, Baltimore, MD 21205 USA
[2] Johns Hopkins Univ, Sch Med, Neurosci Intens Care Nursery Program, Baltimore, MD USA
[3] Johns Hopkins Univ, Sch Med, Dept Pediat, Div Cardiol, Baltimore, MD 21205 USA
[4] Harvard Med Sch, Boston Childrens Hosp, Dept Newborn Med, Boston, MA USA
[5] Johns Hopkins Univ, Sch Med, Dept Pediat, Div Neonatol, Baltimore, MD 21205 USA