title: The human first cell cycle: impact on implantation.
abstract: The morphology of fertilization events has been related to successful implantation by subjective criteria (pronuclei score, pronuclei symmetry and position). This work first described these events by time-lapse technology and then compared the timings of fertilization events (second polar body extrusion, first and second pronuclei appearance, abuttal and fading) in implanted versus nonimplanted embryos in a 2-year cohort retrospective study. A total of 1448 transferred embryos from 842 patients undergoing intracytoplasmic sperm injection with oocyte donation were monitored, 212 embryos from treatments where the number of gestational sacs matched the number of transferred embryos and 687 embryos from treatments no biochemical pregnancy was achieved. The timings at which second polar body extrusion (3.3-10.6 h), pronuclear fading (22.2-25.9 h) and length of S-phase (5.7-13.8 h) occurred were linked successfully to embryo implantation. The other parameters were apparently not related, as determined by image acquisition and time-lapse analysis.
authors.affiliation: IVI Vigo, Plaza Francisco Fernández de Riego, 7, 36203 Vigo, Pontevedra, Spain. Electronic address: jesus.aguilar@ivi.es.
authors.forename: Jesús
authors.initials: J
authors.lastname: Aguilar
authors.affiliation: Instituto Valenciano de Infertilidad, Universidad de Valencia, Plaza de la Policía Local, 3, Valencia 46015, Spain.
authors.forename: Yamileth
authors.initials: Y
authors.lastname: Motato
authors.affiliation: Instituto Valenciano de Infertilidad, Universidad de Valencia, Plaza de la Policía Local, 3, Valencia 46015, Spain.
authors.forename: María José
authors.initials: MJ
authors.lastname: Escribá
authors.affiliation: IVI Vigo, Plaza Francisco Fernández de Riego, 7, 36203 Vigo, Pontevedra, Spain.
authors.forename: María
authors.initials: M
authors.lastname: Ojeda
authors.affiliation: IVI Vigo, Plaza Francisco Fernández de Riego, 7, 36203 Vigo, Pontevedra, Spain.
authors.forename: Elkin
authors.initials: E
authors.lastname: Muñoz
authors.affiliation: Instituto Valenciano de Infertilidad, Universidad de Valencia, Plaza de la Policía Local, 3, Valencia 46015, Spain.
authors.forename: Marcos
authors.initials: M
authors.lastname: Meseguer
mesh_terms: D010064:Embryo Implantation; D005260:Female; D006801:Humans; D011247:Pregnancy; D020554:Sperm Injections, Intracytoplasmic; D059008:Time-Lapse Imaging
keywords: S-phase; cell cycle; early fertilization events; known implantation; pronuclei; time-lapse