title: Human embryo biopsy on the 2nd day after insemination for preimplantation diagnosis: removal of a quarter of embryo retards cleavage.
abstract: OBJECTIVE
  To assess any reduction in viability and development in vitro after biopsy of a quarter of the cells of human embryos on day 2 after insemination.
  
  
  METHODS
  A prospective study in which normally fertilized surplus embryos of good morphology with two to eight cells approximately 48 hours after insemination were randomly allocated to a control or biopsied group, respectively.
  
  
  METHODS
  In vitro fertilization (IVF) unit and laboratories of the Hammersmith Hospital, Institute of Obstetrics and Gynaecology, London University.
  
  
  METHODS
  One hundred twenty-nine embryos from 28 infertile IVF patients.
  
  
  METHODS
  Follicular aspiration by ultrasound-guided transvaginal puncture and embryo biopsy by micromanipulative procedures.
  
  
  METHODS
  Pyruvate uptake and cell number at the blastocyst stage.
  
  
  RESULTS
  Embryo biopsy did not have an adverse effect on either the proportion developing to the blastocyst stage (50% [32 of 64] and 47.7% [31 of 65] for the control and biopsied groups, respectively) or embryo viability, measured indirectly through pyruvate uptake. However, the proportion of embryos that reached the morula stage after day 4 (retarded embryos) was significantly higher (44%, 11 of 25 versus 8.7%, 2 of 23) in the biopsied group. The total number of cells (29.6 +/- 3.1 versus 62.4 +/- 4.7), numbers of inner cell mass (7.7 +/- 2.2 versus 24.5 +/- 1.4) and trophectoderm (24.0 +/- 5.2 versus 45.0 +/- 6.4) cells, and the inner cell mass:trophectoderm ratio (34.7 +/- 7.9 versus 59.5 +/- 11.7) were strikingly reduced at the blastocyst stage in the biopsied group. This reduction was greater in embryos that reached the morula stage after day 4.
  
  
  CONCLUSIONS
  More investigation is needed to assess whether the detrimental effects observed were because of the biopsy method used in this study or to a high sensitivity of human embryos at early stages to manipulation in vitro.
authors.affiliation: Institute of Obstetrics and Gynaecology, Royal Postgraduate Medical School, Hammersmith Hospital, London, United Kingdom.
authors.forename: J J
authors.initials: JJ
authors.lastname: Tarín
authors.forename: J
authors.initials: J
authors.lastname: Conaghan
authors.forename: R M
authors.initials: RM
authors.lastname: Winston
authors.forename: A H
authors.initials: AH
authors.lastname: Handyside
mesh_terms: D001706:Biopsy; D001755:Blastocyst / Q000166:cytology; D002452:Cell Count; D002970:Cleavage Stage, Ovum / Q000502:physiology*; D004622:Embryo, Mammalian / Q000502:physiology*; D047108:Embryonic Development; D005260:Female; D005307:Fertilization in Vitro; D006801:Humans; D009028:Morula / Q000502:physiology; D011247:Pregnancy; D011446:Prospective Studies; D011773:Pyruvates / Q000378:metabolism; D019289:Pyruvic Acid
chemical_list: D011773:Pyruvates; D019289:Pyruvic Acid