[1] Inst Nacl Perinatol Isidro Espinosa de los Reyes, Dept Ginecol & Obstet, Mexico City, Mexico
[2] Inst Nacl Perinatol Isidro Espinosa de los Reyes, Dept Inmunobioquim, Mexico City, Mexico
[3] Univ Nacl Autonoma Mexico, Fac Ciencias, Dept Matemat, Mexico City, Mexico
[4] Hosp Gen Zona 252, Inst Mexicano Seguro Social, Dept Ginecol, Atlacomulco, Mexico
[5] Hosp Gen Leon, Dept Ginecol, Leon, Mexico
[6] Inst Nacl Perinatol Isidro Espinosa de los Reyes, Subdirecc Serv Auxiliares Diagnost, Mexico City, Mexico
[7] Inst Nacl Perinatol Isidro Espinosa de los Reyes, Dept Salud Sexual & Reprod, Mexico City, Mexico
[8] Inst Nacl Perinatol Isidro Espinosa de los Reyes, Dept Salud Sexual & Reprod, Montes Urales 800 Col Lomas de Virreyes, Mexico City 11000, Mexico