1. Obstetrics and Gynecology, Kaiser Antioch Medical Center, Antioch, California, USA.
2. Division of Research, Kaiser Permanente Northern California, Oakland, California, USA.
3. Obstetrics and Gynecology, Kaiser Pleasanton Medical Center, Pleasanton, California, USA.
4. The Permanente Medical Group, Regional Offices, Oakland, California, USA.
5. Psychiatry, Walnut Creek Medical Center, Walnut Creek, California, USA.