1. Magee-Womens Research Institute, Pittsburgh, Pennsylvania, , Department of Obstetrics, Gynecology, and Reproductive Sciences, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
2. Magee-Womens Research Institute, Pittsburgh, Pennsylvania, Department of Epidemiology, University of Pittsburgh Graduate School of Public Health, Pittsburgh, Pennsylvania
3. Magee-Womens Research Institute, Pittsburgh, Pennsylvania, Department of Obstetrics, Gynecology, and Reproductive Sciences, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, Department of Epidemiology, University of Pittsburgh Graduate School of Public Health, Pittsburgh, Pennsylvania
4. Magee-Womens Research Institute, Pittsburgh, Pennsylvania
5. Department of Obstetrics and Gynecology, University of Kentucky, Lexington