1. Magee-Womens Research Institute University of Pittsburgh , Pittsburgh, Pennsylania, Department of Obstetrics and Gynecology and Reproductive Sciences University of Pittsburgh, Pittsburgh, Pennsylania,
2. Magee-Womens Research Institute University of Pittsburgh , Pittsburgh, Pennsylania, Department of Obstetrics and Gynecology and Reproductive Sciences University of Pittsburgh, Pittsburgh, Pennsylania
3. Department of Epidemiology University of Pittsburgh, Pittsburgh, Pennsylvania
4. Magee-Womens Research Institute University of Pittsburgh , Pittsburgh, Pennsylania, Department of Epidemiology University of Pittsburgh, Pittsburgh, Pennsylvania, Department of Obstetrics and Gynecology and Reproductive Sciences University of Pittsburgh, Pittsburgh, Pennsylania