title: Predictive value of spindle retardance in embryo implantation rate.
abstract: OBJECTIVE
  We evaluated the relationship between meiotic spindle characteristics and in vitro fertilization cycle outcome.
  
  
  METHODS
  Five hundred sixty-nine oocytes from 86 in vitro fertilization cycles were analyzed for fertilization and subsequent implantation rates. Oocytes were assessed for maturation status. The oocytes and embryos were cultured in sequential and nonsequential media (G Series, Vitrolife, Sweden) and incubated in 6% CO2, 5% O2at 37 °C. Two hours following oocyte decumulation (38-39 h post-hCG/GnRH administration) and prior to microinjection, the structure of the meiotic spindle was assessed using the Oosight Imaging System (CRI, UK).
  
  
  RESULTS
  Four hundred fifty-six oocytes (80.5%) had a visible meiotic spindle, 82 (14.7%) had no meiotic spindle, and 31 (5.5%) were in telophase I. Oocytes exhibiting a meiotic spindle had a significantly higher fertilization rate and a lower rate of abnormal fertilization. Implantation data were obtained for 195 of the embryos transferred. The implantation rate for embryos derived from oocytes with a meiotic spindle was 32.9%, while in embryos originating from oocytes without a meiotic spindle and oocytes in telophase, this value dropped significantly (8.8 and 0%, respectively). To determine the correlation between retardance values and implantation rate for each oocyte, we established four groups, finding a range of retardance values with significantly higher implantation rates (27.5, 21, 29.3, and 53.8%, respectively).
  
  
  CONCLUSIONS
  Meiotic spindle imaging may be a valuable tool for prediction of oocyte quality, and retardance values of meiotic spindles, together with classical morphological classification, can be useful to select embryos with a higher implantation potential.
authors.affiliation: Equipo Ron - Hospital Quirón A Coruña, C/Londres 2, 15009, A Coruña, Spain.
authors.forename: Sabela
authors.initials: S
authors.lastname: García-Oro
authors.affiliation: Equipo Ron - Hospital Quirón A Coruña, C/Londres 2, 15009, A Coruña, Spain.
authors.forename: María Isabel
authors.initials: MI
authors.lastname: Rey
authors.affiliation: Equipo Ron - Hospital Quirón A Coruña, C/Londres 2, 15009, A Coruña, Spain.
authors.forename: Marta
authors.initials: M
authors.lastname: Rodríguez
authors.affiliation: Equipo Ron - Hospital Quirón A Coruña, C/Londres 2, 15009, A Coruña, Spain.
authors.forename: Ángel
authors.initials: Á
authors.lastname: Durán
authors.affiliation: Equipo Ron - Hospital Quirón A Coruña, C/Londres 2, 15009, A Coruña, Spain.
authors.forename: Roque
authors.initials: R
authors.lastname: Devesa
authors.affiliation: Department Biochemistry, Genetics and Immunology, Faculty of Biology, University of Vigo, Campus, As Lagoas Marcosende S/N, 36310, Vigo, Spain. dianaval@uvigo.es.|Instituto de Investigación Sanitaria Galicia Sur, Pontevedra, Spain. dianaval@uvigo.es.
authors.forename: Diana
authors.identifier: http://orcid.org/0000-0002-7024-1657
authors.initials: D
authors.lastname: Valverde
mesh_terms: D006063:Chorionic Gonadotropin / Q000008:administration & dosage; D010064:Embryo Implantation / Q000187:drug effects; D047108:Embryonic Development; D005260:Female; D005307:Fertilization in Vitro; D007987:Gonadotropin-Releasing Hormone / Q000008:administration & dosage; D006801:Humans; D008297:Male; D008859:Microscopy, Polarization; D009865:Oocytes / Q000187:drug effects / Q000648:ultrastructure*; D011247:Pregnancy; D020554:Sperm Injections, Intracytoplasmic; D008941:Spindle Apparatus / Q000187:drug effects / Q000648:ultrastructure*; D013548:Sweden
chemical_list: D006063:Chorionic Gonadotropin; D007987:Gonadotropin-Releasing Hormone
keywords: Embryo implantation; Embryo selection; Meiotic spindle; Oocyte quality