1. The Ohio State University; Division of Epidemiology; Room 324 Cunz Hall 1841 Neil Avenue Columbus Ohio USA 43210-1351
2. FHI 360; Clinical Sciences; 359 Blackwell St, Suite 200 Durham North Carolina USA 27701
3. University of North Carolina, School of Medicine; Obstetrics and Gynecology; CB#7570 Chapel Hill North Carolina USA 27599-7570
4. FHI360; Clinical Sciences; Durham North Carolina USA 27701
5. FHI 360 and UNC School of Medicine; Quantitative Sciences; P.O. Box 13950 Research Triangle Park North Carolina USA NC 27709
6. Leiden University Medical Center; Department of Gynaecology, Division of Reproductive Medicine and Dept. of Clinical Epidemiology; PO Box 9600 Albinusdreef 2 Leiden Netherlands NL 2300 RC