title: Blastocyst development in single medium with or without renewal on day 3: a prospective cohort study on sibling donor oocytes in a time-lapse incubator.
abstract: OBJECTIVE
  To evaluate the efficiency of using a continuous (one-step) protocol with a single medium for the culture of human embryos in a time-lapse incubator (TLI).
  
  
  METHODS
  Prospective cohort study on sibling donor oocytes.
  
  
  METHODS
  University-affiliated in vitro fertilization (IVF) center.
  
  
  METHODS
  Embryos from 59 patients.
  
  
  METHODS
  Culture in a TLI in a single medium with or without renewal of the medium on day-3.
  
  
  METHODS
  Embryo morphology and morphokinetic parameters, clinical pregnancy, take-home baby rate, and perinatal outcomes.
  
  
  RESULTS
  The blastocyst rates (68.3 vs. 66.8%) and the proportion of good-quality blastocysts (transferred plus frozen) obtained with the two-step (80.0%) protocol were statistically significantly similar to those obtained in the one-step protocol (72.2%). Similarly, morphokinetic events from early cleavage until late blastocyst stages were statistically significantly equivalent between both groups. No differences were found either in clinical pregnancy rates when comparing pure transfers performed with embryos selected from the two-step (75.0%), one-step (70.0%, respectively), and mixed (57.1%) groups. A total of 55 out of 91 embryos transferred implanted successfully (60.4%), resulting in a total of 37 newborns with a comparable birth weight mean among groups.
  
  
  CONCLUSIONS
  Our findings support the idea that in a TLI with a controlled air purification system, human embryos can be successfully cultured continuously from day 0 onward in single medium with no need to renew it on day-3. This strategy does not affect embryo morphokinetics or development to term and offers more stable culture conditions for embryos as well as practical advantages and reduced costs for the IVF laboratory.
authors.affiliation: Embryotools, Barcelona, Spain. Electronic address: nuno.borges@embryotools.com.
authors.forename: Nuno
authors.initials: N
authors.lastname: Costa-Borges
authors.affiliation: IVI-Barcelona, Barcelona, Spain.
authors.forename: Marta
authors.initials: M
authors.lastname: Bellés
authors.affiliation: IVI-Valencia, Valencia, Spain.
authors.forename: Marcos
authors.initials: M
authors.lastname: Meseguer
authors.affiliation: IVI-Barcelona, Barcelona, Spain.
authors.forename: Daniela
authors.initials: D
authors.lastname: Galliano
authors.affiliation: IVI-Barcelona, Barcelona, Spain.
authors.forename: Agustin
authors.initials: A
authors.lastname: Ballesteros
authors.affiliation: Embryotools, Barcelona, Spain.
authors.forename: Gloria
authors.initials: G
authors.lastname: Calderón
mesh_terms: D001724:Birth Weight; D001755:Blastocyst / Q000378:metabolism / Q000502:physiology*; D003470:Culture Media / Q000378:metabolism*; D046149:Embryo Culture Techniques / Q000295:instrumentation*; D004624:Embryo Transfer; D004867:Equipment Design; D005260:Female; D005298:Fertility; D005307:Fertilization in Vitro; D005865:Gestational Age; D006801:Humans; D007185:Incubators; D007231:Infant, Newborn; D007246:Infertility / Q000175:diagnosis / Q000503:physiopathology / Q000628:therapy*; D050498:Live Birth; D008853:Microscopy / Q000295:instrumentation*; D009024:Morphogenesis; D011247:Pregnancy; D018873:Pregnancy Rate; D011446:Prospective Studies; D013997:Time Factors; D059008:Time-Lapse Imaging / Q000295:instrumentation*; D016896:Treatment Outcome
chemical_list: D003470:Culture Media
keywords: Morphokinetic events; single-step medium; time-lapse incubator; uninterrupted culture