1. Department of Pediatrics, School of Medicine, Texas Tech University Health Sciences Center, 1400 Wallace Boulevard, Amarillo, TX 79106, USA
2. Infant Risk Center, Texas Tech University Health Sciences Center, 1400 Wallace Boulevard, Amarillo, TX 79106, USA
3. Department of Obstetrics & Gynecology, School of Medicine, Texas Tech University Health Sciences Center, 1400 Coulter Street, Amarillo, TX 79106, USA