1. Department of Obstetrics and Gynecology, University of Tennessee Health Science Center, Memphis, TN, USA
2. Department of Obstetrics and Gynecology, University of South Florida, Tampa, FL, USA
3. Department of Epidemiology, University of Tennessee Health Science Center, Memphis, TN, USA
4. Department of Biostatistics, Florida International University, Miami, FL, USA
5. Department of Pediatrics, University of South Florida, Tampa, FL, USA