title: Zona pellucida removal and vitrified blastocyst transfer outcome: a preliminary study.
abstract: The objective of this study was to investigate whether a change in assisted hatching technique from partial opening to total removal of the zona pellucida improved the outcome of vitrified blastocyst transfer. This was a preliminary observational study conducted from November 2003 to April 2006. Partial opening using acid Tyrode's solution was performed in 45 cycles, while total removal using a laser and mechanical pipetting was performed in 57 cycles. The clinical pregnancy, implantation, and delivery rates were higher in the total removal group than in the partial opening group (67% versus 42%, P < 0.02; 55% versus 30%, P < 0.01; 56% versus 36%, P < 0.04, respectively). These results suggest that total removal of the zona pellucida is associated with higher pregnancy, implantation and delivery rates compared with partial opening for vitrified blastocyst transfer.
authors.affiliation: Kinutani Women's Clinic, 2-1-4-3F, Ohtemachi, Hiroshima 730-0051, Japan. hiraoka@chive.ocn.ne.jp
authors.forename: Kenichiro
authors.initials: K
authors.lastname: Hiraoka
authors.forename: Megumi
authors.initials: M
authors.lastname: Fuchiwaki
authors.forename: Kaori
authors.initials: K
authors.lastname: Hiraoka
authors.forename: Toshitaka
authors.initials: T
authors.lastname: Horiuchi
authors.forename: Tomoyo
authors.initials: T
authors.lastname: Murakami
authors.forename: Masayuki
authors.initials: M
authors.lastname: Kinutani
authors.forename: Kazuo
authors.initials: K
authors.lastname: Kinutani
mesh_terms: D000328:Adult; D015925:Cryopreservation; D046149:Embryo Culture Techniques; D004624:Embryo Transfer; D005260:Female; D005307:Fertilization in Vitro / Q000379:methods*; D006801:Humans; D007552:Isotonic Solutions; D007834:Lasers; D010865:Pilot Projects; D011247:Pregnancy; D011256:Pregnancy Outcome; D012189:Retrospective Studies; D015044:Zona Pellucida
chemical_list: D007552:Isotonic Solutions; C037692:Tyrode's solution