title: Higher implantation rate using modified quarter laser-assisted zona thinning in repeated implantation failure.
abstract: OBJECTIVE
  Some embryo implantation problems in patients with recurrent implantation failure may be explained by the inability of the embryo to hatch out of its zona pellucida. In this case-control study, a study group which had received modified quarter laser-assisted zona thinning (mQLAZT) was compared with a control group which had not received mQLAZT with respect to reproductive outcome.
  
  
  METHODS
  Cycles from patients with a 4th fresh embryo transfer (ET) after 3 previously failed ET cycles (no beta-hCG detected) were included. Cases (group A, n = 53) included ET cycles from patients who received a 4th ET with fresh embryos after mQLAZT. Controls (group B, n = 86) included ET cycles from patients who had a 4th ET without mQLAZT. The clinical implantation rate and live birth rate per embryo transferred were measured.
  
  
  RESULTS
  The clinical implantation rate with positive fetal heart beat per embryo transferred was significantly higher (p = 0.035) in group A (22/107 or 21%) than in group B (18/166 or 11%).
  
  
  CONCLUSIONS
  The data of this case-control study suggest that mQLAZT can be effective in the treatment of patients with recurrent implantation failure, but need to be confirmed by randomized trials.
authors.affiliation: Leuven University Fertility Center, UZ Gasthuisberg, Leuven, Belgium. sophie.debrock@uzleuven.be
authors.forename: Sophie
authors.initials: S
authors.lastname: Debrock
authors.forename: Carl
authors.initials: C
authors.lastname: Spiessens
authors.forename: Karen
authors.initials: K
authors.lastname: Peeraer
authors.forename: Peter
authors.initials: P
authors.lastname: De Loecker
authors.forename: Dorien
authors.initials: D
authors.lastname: Willemen
authors.forename: Thomas M
authors.initials: TM
authors.lastname: D'Hooghe
mesh_terms: D000328:Adult; D016022:Case-Control Studies; D003131:Combined Modality Therapy; D010064:Embryo Implantation; D004624:Embryo Transfer / Q000009:adverse effects / Q000379:methods* / Q000706:statistics & numerical data*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007247:Infertility, Female / Q000175:diagnosis / Q000628:therapy; D053685:Laser Therapy / Q000379:methods*; D011247:Pregnancy; D011256:Pregnancy Outcome; D018873:Pregnancy Rate; D015995:Prevalence; D011336:Probability; D012016:Reference Values; D019233:Retreatment; D012189:Retrospective Studies; D018570:Risk Assessment; D016896:Treatment Outcome; D015044:Zona Pellucida