title: [Combined hormonal contraception in cycles artificially extended].
authors.affiliation: Servicio de Ginecología, Hospital Central Norte PEMEX.
authors.forename: Edgardo
authors.initials: E
authors.lastname: Bustillos-Alamilla
authors.forename: J
authors.initials: J
authors.lastname: Zepeda-Zaragoza
authors.forename: M A
authors.initials: MA
authors.lastname: Hernández-Ruiz
authors.forename: Carlos Humberto
authors.initials: CH
authors.lastname: Briones-Landa