1. Department of Pediatrics, Medical University of South Carolina, 135 Rutledge Avenue, P.O. Box 250561, Charleston, SC 29425, USA
2. Department of Obstetrics and Gynecology, Medical University of South Carolina, Charleston, SC 29425, USA
3. Department of Obstetrics and Gynecology, Southern Illinois University School of Medicine, Springfield, IL 62794, USA
4. Department of Health Science and Research, Medical University of South Carolina, Charleston, SC 29425, USA