[1] Fudan Univ, Shanghai Inst Planned Parenthood Res, NHC Key Lab Reprod Regulat, Shanghai, Peoples R China
[2] Karolinska Inst, Dept Global Publ Hlth, Global & Sexual Hlth, Stockholm, Sweden
[3] Univ Ghent, Fac Med & Hlth Sci, Int Ctr Reprod Hlth ICRH, Ghent, Belgium
[4] Johns Hopkins Bloomberg Sch Publ Hlth, Dept Populat Family & Reprod Hlth, Baltimore, MD USA
[5] CESP Ctr Res Epidemiol & Populat Hlth, Soins Primaires & Prevent, Villejuif, France
[6] Rutgers, Utrecht, Netherlands