1. Department of OB/Gyn, Wake Forest University School of Medicine, Winston Salem, North Carolina, USA.
2. Gillings School of Global Public Health, Department of Epidemiology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA.
3. Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA.
4. Shady Grove Fertility, Raleigh, North Carolina, USA.
5. Department of Research and Evaluation, Kaiser Permanente Southern California, Pasadena, California, USA.
6. Department of Health Systems Science, Kaiser Permanente Bernard J. Tyson School of Medicine, Pasadena, California, USA.
7. Division of Research, Kaiser Permanente Northern California, Oakland, California, USA.