title: A comparison of four different techniques of assisted hatching.
abstract: BACKGROUND
  Assisted hatching (AH) has been proposed as a means to increase the implantation rate in patients with poor prognosis for pregnancy. The procedure appears to be effective when used selectively. Several different methods for AH have been introduced over the years but comparative studies are lacking. The aim of the current study was to compare retrospectively the efficacy of AH performed with four different methods in patients undergoing IVF or ICSI.
  
  
  METHODS
  AH was performed prior to day 3 embryo transfer in 794 IVF/ICSI cycles. Indications for AH were females aged >35 years and/or elevated follicular phase FSH levels, previous failed IVF/ICSI cycles, poor embryo quality, and thick zona pellucida (>15 microm). Assignment to one of the four methods of AH was according to the availability of the particular method during the study period. The study was not randomized.
  
  
  RESULTS
  Partial zona dissection was used in 239, acid Tyrode in 191, diode laser in 219 and pronase thinning of the zona pellucida in 145. Mean female age, mean number of previous failed IVF/ICSI cycles, number of oocytes retrieved, fertilization and cleavage rates, good quality embryos and zona thickness on day 3 did not differ between groups. Mean number of embryos transferred, implantation rate, clinical pregnancy rate, and abortion rates were likewise similar.
  
  
  CONCLUSIONS
  Selective AH using four different methods yields similar implantation and pregnancy rates.
authors: Assisted Reproduction Unit, American Hospital of Istanbul, Istanbul, Turkey.
authors: Basak
authors: B
authors: Balaban
authors: Bulent
authors: B
authors: Urman
authors: Cengiz
authors: C
authors: Alatas
authors: Ramazan
authors: R
authors: Mercan
authors: Alper
authors: A
authors: Mumcu
authors: Aycan
authors: A
authors: Isiklar
mesh_terms: D000328:Adult; D004210:Dissection; D010064:Embryo Implantation; D005260:Female; D005307:Fertilization in Vitro; D006801:Humans; D007552:Isotonic Solutions / Q000627:therapeutic use; D053685:Laser Therapy; D011247:Pregnancy; D018873:Pregnancy Rate; D011402:Pronase / Q000627:therapeutic use; D027724:Reproductive Techniques, Assisted / Q000592:standards*; D012189:Retrospective Studies; D020554:Sperm Injections, Intracytoplasmic; D015044:Zona Pellucida / Q000187:drug effects
chemical_list: D007552:Isotonic Solutions; C037692:Tyrode's solution; D011402:Pronase