1. Division of Intramural Population Health Research (K.C.S., S.L.M., K.A.K., L.A.S., N.J.P., K.A.A., P.M., E.F.S.), Maryland 20852
2. Departments of Obstetrics and Gynecology (A.O.H.), University of Utah, Salt Lake City, Utah 84132
3. Department of Family and Preventative Medicine (A.O.H., J.B.S.), University of Utah, Salt Lake City, Utah 84106
4. Program of Reproductive and Adult Endocrinology (K.A.K.), Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Rockville, Maryland 20852
5. Department of Social and Preventive Medicine (J.W.-W.), State University of New York at Buffalo, Buffalo, New York 14209