[1] Univ Buenos Aires, Sch Med, Affiliated Hosp, Dept Obstet & Gynaecol,CEMIC, RA-1053 Buenos Aires, DF, Argentina
[2] IMBICE, ECLAMC, La Plata, Buenos Aires, Argentina
[3] CEMIC, ECLAMC, Buenos Aires, DF, Argentina
[4] FIOCRUZ, Inst Oswaldo Cruz, ECLAMC, Rio De Janeiro, Brazil
[5] Georgetown Univ, Med Ctr, Dept Obstet & Gynaecol, Washington, DC 20007 USA
[6] Baylor Sch Med, Dept Obstet & Gynaecol, Houston, TX USA
[7] Georgetown Univ, Inst Reprod Hlth, Washington, DC USA