[1] Kaiser Permanente, Div Res, Kaiser Fdn Res Inst, Oakland, CA USA
[2] Fudan Univ, Dept Occupat Hlth & Toxicol, Sch Publ Hlth, Shanghai, Peoples R China
[3] Fudan Univ, WHO Collaborating Ctr Occupat Hlth, Shanghai, Peoples R China
[4] Shanghai Inst Planned Parenthood Res, Dept Epidemiol & Social Sci Reprod Hlth, Shanghai, Peoples R China
[5] WHO Collaborating Ctr Res Human Reprod, New York, NY USA
[6] Shanxi Med Univ, Dept Epidemiol, Taiyuan, Peoples R China
[7] Natl Populat & Family Planning Key Lab Contracept, Shanghai, Peoples R China