title: Assisted hatching by partial zona dissection of human pre-embryos in patients with recurrent implantation failure after in vitro fertilization.
abstract: OBJECTIVE
  To examine the potential of the partial zona dissection technique to promote successful implantation by assisting embryo hatching after IVF.
  
  
  METHODS
  The study and the control group included 72 and 82 patients, respectively, each had undergone at least three failed IVF-ET attempts. Assisted hatching was performed on four- to six-cell stage embryos by creating a slit in the zona pellucida using the partial zona dissection technique. After 90 minutes incubation (5% CO2, 37 degrees C), the embryos were transferred to the uterus.
  
  
  METHODS
  Infertility and IVF Unit of an academic tertiary referral medical center.
  
  
  RESULTS
  In the assisted hatching group, 230 micromanipulated embryos were replaced (3 or 4 treated embryos per patient) compared with 295 nonmanipulated embryos in the control group. Clinical pregnancy rates (PRs) were similar in the assisted hatching and control groups (n = 15; 20.8% and n = 12; 14.6%, respectively). However, the contribution of assisted hatching by partial zona dissection to successful implantation was related to the patients's age: patients older than 38 years showed a markedly higher PR after assisted hatching: 23.9% in the study group compared with only 7% of the controls.
  
  
  CONCLUSIONS
  These results demonstrate that assisted hatching by partial zona dissection is a quick and efficient method that does not induce any visible damage to the embryos replaced. In a selected group of patients (aged over 38 years, who have failed to conceive in at least three previous IVF attempts) it significantly increases the chances for pregnancy after ET.
authors.affiliation: Department of Obstetrics and Gynecology, Beilinson Medical Center, Petah Tiqva, Israel.
authors.forename: A
authors.initials: A
authors.lastname: Stein
authors.forename: O
authors.initials: O
authors.lastname: Rufas
authors.forename: S
authors.initials: S
authors.lastname: Amit
authors.forename: O
authors.initials: O
authors.lastname: Avrech
authors.forename: H
authors.initials: H
authors.lastname: Pinkas
authors.forename: J
authors.initials: J
authors.lastname: Ovadia
authors.forename: B
authors.initials: B
authors.lastname: Fisch
mesh_terms: D000328:Adult; D000375:Aging / Q000502:physiology; D001755:Blastocyst / Q000502:physiology*; D004210:Dissection; D010064:Embryo Implantation; D005260:Female; D005307:Fertilization in Vitro / Q000379:methods*; D006801:Humans; D008846:Micromanipulation; D011247:Pregnancy; D012099:Reproductive Techniques; D017211:Treatment Failure; D015044:Zona Pellucida