[1
]Division of Perinatal MedicineDepartment of PediatricsYale University School of MedicineNew
HavenConnecticut06510USA
[2
]Department of MedicineDuke University Medical Center, and Veterans Affairs Medical
CenterDurhamNorth Carolina27710USA
[3
]Departments of Biochemistry and Obstetrics and GynecologyThe Cecil H. and Ida Green
Center for Reproductive Biology SciencesThe University of Texas Southwestern Medical
CenterDallasTexas75235USA