[1] Univ Coahuila, Biomed Res Ctr, Torreon, Coahuila, Mexico
[2] Ctr Estrateg Conad Latinoamer S A de C V Mexico, Mexico City, DF, Mexico
[3] Del Valle Univ Hosp, Cali, Colombia
[4] San Paul Univ Hosp, Medellin, Colombia
[5] San Jose Univ Hosp, Bogota, Colombia
[6] Clin Country, Bogota, Colombia
[7] San Ignacio Univ Hosp, Bogota, Colombia
[8] Univ Sao Paulo, Med Sch Ribeirao Preto, Sao Paulo, Brazil
[9] Univ Estado Rio De Janeiro, Univ Hosp, Rio De Janeiro, Brazil
[10] Junin Private Clin, Ginaecol Serv, Cordova, Argentina
[11] Fernandez Hosp, Ginaecol Serv, Buenos Aires, DF, Argentina
[12] Univ Nacl Rosario, Hosp Centenario, Sch Med, Ctr Human Reprod,Ginaecol Serv, RA-2000 Rosario, Santa Fe, Argentina
[13] Univ Buenos Aires, Jose de San Martin Hosp Clin, Sch Med, Ginaecol Serv, Buenos Aires, DF, Argentina
[14] Univ Buenos Aires, Bernardino Rivadavia Hosp, Sch Med, Ginaecol Serv, Buenos Aires, DF, Argentina
[15] Model Inst Ginaecol & Obstet, IMCO, Cordova, Argentina
[16] Natl Inst Perinatol, Mexico City, DF, Mexico
[17] Ctr Human Reprod Attendance, Mexico City, DF, Mexico
[18] Occident Med Inst, Guadalajara, Jalisco, Mexico
[19] IMSS, Gineobstet Hosp, Castelazo Ayala, Mexico City, DF, Mexico
[20] Juarez Univ Durango, Res Inst, Reprod Hlth Dept, Durango, Mexico
[21] Ginaecol Serv Sanez Pena, Rosario, Santa Fe, Argentina