title: Spindle imaging: a marker for embryo development and implantation.
abstract: OBJECTIVE
  To examine whether the presence of birefringent spindles in living human oocytes can be used as a predictive factor associated with embryo morphology to allow embryo selection before transfer and its association with IVF outcomes.
  
  
  METHODS
  Prospective study.
  
  
  METHODS
  Assisted reproduction center in Brazil.
  
  
  METHODS
  One hundred fifty-seven patients undergoing intracytoplasmic sperm injection cycles, resulting in 1,097 metaphase II oocytes.
  
  
  METHODS
  Meiotic spindles were evaluated before intracytoplasmic sperm injection in all metaphase II oocytes.
  
  
  METHODS
  Meiotic spindles' imaging and fertilization rate, embryo development, and implantation rate.
  
  
  RESULTS
  Birefringent spindles were detected in 65.9% (SD group). The normal fertilization rate and rate of early-cleavaged embryos were higher in the SD group compared with in the spindle-non-detected (SND) group. When only embryos from the SD group were selected for transfer, the pregnancy and implantation rates were 44.4% and 23.0%, and when only embryos from the SND group were transferred, those rates were 18.2% and 8.7%, respectively (statistically significant differences).
  
  
  CONCLUSIONS
  Spindle visualization can be an important tool for predicting better fertilization potential, embryo development, and clinical outcomes, suggesting that embryo selection for transfer may be based not only on embryo morphology but also on oocyte nuclear maturity.
authors.affiliation: Fertility-Assisted Fertilization Center, São Paulo, Brazil.
authors.forename: Camila
authors.initials: C
authors.lastname: Madaschi
authors.forename: Tatiana Carvalho
authors.initials: TC
authors.lastname: de Souza Bonetti
authors.forename: Daniela Paes
authors.initials: DP
authors.lastname: de Almeida Ferreira Braga
authors.forename: Fabio Firmbach
authors.initials: FF
authors.lastname: Pasqualotto
authors.forename: Assumpto
authors.initials: A
authors.lastname: Iaconelli
authors.forename: Edson
authors.initials: E
authors.lastname: Borges
mesh_terms: D000328:Adult; D001718:Birefringence; D001938:Brazil; D010064:Embryo Implantation; D004624:Embryo Transfer; D047108:Embryonic Development; D005260:Female; D006801:Humans; D007246:Infertility / Q000628:therapy*; D008540:Meiosis; D008859:Microscopy, Polarization; D054315:Oocyte Retrieval; D009865:Oocytes / Q000254:growth & development / Q000648:ultrastructure*; D011247:Pregnancy; D011446:Prospective Studies; D020554:Sperm Injections, Intracytoplasmic; D008941:Spindle Apparatus / Q000648:ultrastructure*; D016896:Treatment Outcome