title: Prospective hatching of embryos developed from oocytes exhibiting difficult oolemma penetration during ICSI.
abstract: BACKGROUND
  The hormonal milieu during ovarian stimulation is known to affect oolemma behaviour as well as zona pellucida thickness and structure. This led us to investigate whether a special subgroup of patients with oocytes where penetration of the oolemma is difficult during ICSI may benefit from assisted hatching.
  
  
  METHODS
  A total of 77 couples (mean age: 32.9 +/- 4.6 years; range: 22-38) had oocytes that could hardly be penetrated by the ICSI pipette. Nineteen patients underwent two ICSI cycles, giving a total number of 96 cycles, which were randomly split into either the study group (n = 52) or the non-hatching group (n = 44). Hatching was done using a non-contact 1.48 mm wavelength diode laser. Implantation and pregnancy rates were recorded.
  
  
  RESULTS
  The pregnancy rate was 36.6% (19/52) in the study group and 13.6% (6/44) in the non-hatching group (P < 0.05). In addition, a higher number (P < 0.05) of embryos implanted in the study group (23/106; 21.7%) than in the non-hatching group (9/92; 9.8%).
  
  
  CONCLUSIONS
  Once oolema penetration during ICSI has proven difficult, prospective hatching of embryos considered for transfer may increase their implantation behaviour.
authors: Women's General Hospital Linz, IVF Unit, Lederergasse 47, A-4020 Linz, Upper Austria, Austria. thomas.ebner@gespag.at
authors: T
authors: T
authors: Ebner
authors: M
authors: M
authors: Moser
authors: C
authors: C
authors: Yaman
authors: M
authors: M
authors: Sommergruber
authors: J
authors: J
authors: Hartl
authors: K
authors: K
authors: Jesacher
authors: G
authors: G
authors: Tews
mesh_terms: D000328:Adult; D010064:Embryo Implantation; D004622:Embryo, Mammalian / Q000502:physiology*; D005260:Female; D006801:Humans; D053685:Laser Therapy; D008297:Male; D011247:Pregnancy; D018873:Pregnancy Rate; D011446:Prospective Studies; D027724:Reproductive Techniques, Assisted; D020554:Sperm Injections, Intracytoplasmic; D015044:Zona Pellucida / Q000502:physiology / Q000528:radiation effects*