title: Assisting in vitro fertilization by manipulating cumulus-oocyte-complexes either mechanically or enzymatically does not prevent IVF failure.
abstract: OBJECTIVE
  This prospective study was set up in order to analyze whether additional treatment (cutting off supernumerous cumulus cells; adding hyaluronidase) of the cumulus-oocyte-complex (COC) would help to improve treatment outcome.
  
  
  METHODS
  COCs from 50 patients were prospectively subdivided into a control group A (no manipulation of COC) and two study groups. In group B, surplus cumulus cells were cut off using syringes, and in the second study group COCs were incubated with a 1:11 dilution of hyaluronidase (final concentration 7 IU/l). Main outcome measures were fertilization rate, embryo development, as well as rates of implantation, pregnancy, and live birth.
  
  
  RESULTS
  Fertilization was higher in group C as compared to the untreated control group A (p<0.05). However, complete fertilization failure could not be avoided by any of the modified IVF approaches. Compaction on day 4 and blastocyst quality on day 5 were significantly improved in group C as compared to group B (but not to group A). Rates of implantation, pregnancy, and live birth were not affected by any of the methods.
  
  
  CONCLUSIONS
  ICSI seems to be the only choice for avoiding the vast majority of fertilization failures after IVF.
authors.affiliation: Landes- Frauen- Und Kinderklinik, Kinderwunsch Zentrum, Linz, Austria.
authors.forename: Thomas
authors.initials: T
authors.lastname: Ebner
authors.affiliation: Landes- Frauen- Und Kinderklinik, Kinderwunsch Zentrum, Linz, Austria.
authors.forename: Marianne
authors.initials: M
authors.lastname: Moser
authors.affiliation: Landes- Frauen- Und Kinderklinik, Kinderwunsch Zentrum, Linz, Austria.
authors.forename: Omar
authors.initials: O
authors.lastname: Shebl
authors.affiliation: Landes- Frauen- Und Kinderklinik, Kinderwunsch Zentrum, Linz, Austria.
authors.forename: Richard
authors.initials: R
authors.lastname: Mayer
authors.affiliation: Landes- Frauen- Und Kinderklinik, Kinderwunsch Zentrum, Linz, Austria.
authors.forename: Gernot
authors.initials: G
authors.lastname: Tews
keywords: Blastocyst; IVF; cumulus-oocyte complex; fertilization; hyaluronidase