1. MRC Centre for Reproductive Health; University of Edinburgh; Queen's Medical Research Institute; Edinburgh UK
2. Department of Obstetrics and Gynaecology; Queen Elizabeth II Research Institute for Mothers and Infants; University of Sydney; Sydney New South Wales Australia
3. Department of Obstetrics and Gynecology; David Geffen School of Medicine; University of California; Los Angeles California USA
4. Gynecologic Services; Kaiser Permanente Los Angeles Medical Center; Los Angeles California USA