[1] Shanghai Inst Biomed & Pharmaceut Technol, Inst publ Hlth & Hlth policy, Shanghai MOST Key Lab Hlth & Dis Genom, NHC Key Lab Reprod Regulat, Shanghai, Peoples R China
[2] Johns Hopkins Bloomberg Sch Publ Hlth, Dept Populat Family & Reprod Hlth, Baltimore, MD USA
[3] Kamuzu Univ Hlth Sci, Malawi Coll Med, Ctr Reprod Hlth, Dept Publ Hlth & Obstet & Gynaecol, Blantyre, Malawi