title: Assisted hatching facilitates earlier implantation.
abstract: OBJECTIVE
  To examine whether opening of the zona pellucida (i.e., assisted hatching) accelerates implantation.
  
  
  METHODS
  In a controlled, randomized trial, patients were assigned to control and assisted hatching groups.
  
  
  METHODS
  All patients studied were of the Center for Reproductive Medicine at Cornell University Medical College.
  
  
  METHODS
  All patients underwent stimulation with gonadotropins after luteal phase GnRH down regulation. Assisted hatching with zona drilling using acidic Tyrode's solution was performed on the assigned embryos.
  
  
  METHODS
  Luteal E2, P, and hCG on days +5, +6, +7, +8, +9, +11, +13, and +15 were measured. The implantation time, peak midluteal E2 and intervals between these two values were studied.
  
  
  RESULTS
  Implantation occurred significantly earlier in the assisted hatching group. The interval between implantation and peak midluteal E2 was also significantly shorter in the assisted hatching group than in the controls. However, there was no significant difference in the day of the peak midluteal E2 between the assisted hatching and control groups.
  
  
  CONCLUSIONS
  Assisted hatching may enhance embryo implantation not only by mechanically facilitating the hatching process but also by allowing earlier embryo-endometrium contact. Such early contact may enhance embryonic development potential and may optimize synchronization between embryo and endometrium, resulting in improved implantation efficiency.
authors.affiliation: Department of Obstetrics and Gynecology, New York Hospital-Cornell Medical Center.
authors.forename: H C
authors.initials: HC
authors.lastname: Liu
authors.forename: J
authors.initials: J
authors.lastname: Cohen
authors.forename: M
authors.initials: M
authors.lastname: Alikani
authors.forename: N
authors.initials: N
authors.lastname: Noyes
authors.forename: Z
authors.initials: Z
authors.lastname: Rosenwaks
mesh_terms: D006063:Chorionic Gonadotropin / Q000097:blood; D010064:Embryo Implantation; D004624:Embryo Transfer; D004958:Estradiol / Q000097:blood; D005260:Female; D005307:Fertilization in Vitro; D006062:Gonadotropins / Q000627:therapeutic use; D006801:Humans; D008183:Luteal Phase / Q000097:blood; D011247:Pregnancy; D011374:Progesterone / Q000097:blood; D011446:Prospective Studies; D012189:Retrospective Studies; D015044:Zona Pellucida
chemical_list: D006063:Chorionic Gonadotropin; D006062:Gonadotropins; D011374:Progesterone; D004958:Estradiol