title: Laser-assisted hatching improves clinical outcomes of vitrified-warmed blastocysts developed from low-grade cleavage-stage embryos: a prospective randomized study.
abstract: The aim of this study was to evaluate the effects of quarter zona-pellucida (ZP) opening by laser-assisted hatching (QLAH) on the clinical outcomes following transfer of vitrified-warmed blastocysts developed from low-grade cleavage-stage embryos in patients with all high-grade and fair-grade cleavage-stage embryos transferred without achieving pregnancy. Patients were randomized into two groups: QLAH (n=101) and control (n=102). The implantation and clinical pregnancy rates were significantly higher in the QLAH group compared with the control group (P=0.021 and P=0.034, respectively). The live birth rate of the QLAH group was also higher, although not significantly. When the clinical outcomes according to the day of blastocyst vitrification were compared between the groups, the implantation, clinical pregnancy and live birth rates of the QLAH group were significantly higher (P<0.05) than those of the control group for day 6 blastocysts, but not for day 5 or day 5/day 6 blastocysts. These results suggest that QLAH improves the clinical outcomes of vitrified-warmed blastocysts, especially of day 6 vitrified blastocysts, developed from low-grade cleavage-stage embryos.
authors.affiliation: Fertility Center, Shenzhen Zhongshan Urology Hospital, Shenzhen 518045, PR China; Shenzhen Key Laboratory of Reproductive Immunology for Peri-implantation, Shenzhen Zhongshan Urological Hospital, Shenzhen 518045, PR China; Shenzhen Zhongshan Institute for Reproduction and Genetics, Shenzhen 518045, PR China.
authors.forename: Cai-Yun
authors.initials: CY
authors.lastname: Wan
authors.affiliation: Fertility Center, Shenzhen Zhongshan Urology Hospital, Shenzhen 518045, PR China; Shenzhen Key Laboratory of Reproductive Immunology for Peri-implantation, Shenzhen Zhongshan Urological Hospital, Shenzhen 518045, PR China; Shenzhen Zhongshan Institute for Reproduction and Genetics, Shenzhen 518045, PR China.
authors.forename: Cheng
authors.initials: C
authors.lastname: Song
authors.affiliation: Fertility Center, Shenzhen Zhongshan Urology Hospital, Shenzhen 518045, PR China; Shenzhen Key Laboratory of Reproductive Immunology for Peri-implantation, Shenzhen Zhongshan Urological Hospital, Shenzhen 518045, PR China; Shenzhen Zhongshan Institute for Reproduction and Genetics, Shenzhen 518045, PR China.
authors.forename: Liang-Hui
authors.initials: LH
authors.lastname: Diao
authors.affiliation: Fertility Center, Shenzhen Zhongshan Urology Hospital, Shenzhen 518045, PR China; Shenzhen Key Laboratory of Reproductive Immunology for Peri-implantation, Shenzhen Zhongshan Urological Hospital, Shenzhen 518045, PR China; Shenzhen Zhongshan Institute for Reproduction and Genetics, Shenzhen 518045, PR China.
authors.forename: Guan-Gui
authors.initials: GG
authors.lastname: Li
authors.affiliation: Fertility Center, Shenzhen Zhongshan Urology Hospital, Shenzhen 518045, PR China; Shenzhen Key Laboratory of Reproductive Immunology for Peri-implantation, Shenzhen Zhongshan Urological Hospital, Shenzhen 518045, PR China; Shenzhen Zhongshan Institute for Reproduction and Genetics, Shenzhen 518045, PR China.
authors.forename: Zhong-Jian
authors.initials: ZJ
authors.lastname: Bao
authors.affiliation: Fertility Center, Shenzhen Zhongshan Urology Hospital, Shenzhen 518045, PR China; Shenzhen Key Laboratory of Reproductive Immunology for Peri-implantation, Shenzhen Zhongshan Urological Hospital, Shenzhen 518045, PR China; Shenzhen Zhongshan Institute for Reproduction and Genetics, Shenzhen 518045, PR China.
authors.forename: Xiao-Dong
authors.initials: XD
authors.lastname: Hu
authors.affiliation: Fertility Center, Shenzhen Zhongshan Urology Hospital, Shenzhen 518045, PR China; Shenzhen Key Laboratory of Reproductive Immunology for Peri-implantation, Shenzhen Zhongshan Urological Hospital, Shenzhen 518045, PR China; Shenzhen Zhongshan Institute for Reproduction and Genetics, Shenzhen 518045, PR China.
authors.forename: Hong-Zhan
authors.initials: HZ
authors.lastname: Zhang
authors.affiliation: Fertility Center, Shenzhen Zhongshan Urology Hospital, Shenzhen 518045, PR China; Shenzhen Key Laboratory of Reproductive Immunology for Peri-implantation, Shenzhen Zhongshan Urological Hospital, Shenzhen 518045, PR China; Shenzhen Zhongshan Institute for Reproduction and Genetics, Shenzhen 518045, PR China. Electronic address: zengyong1966@gmail.com.
authors.forename: Yong
authors.initials: Y
authors.lastname: Zeng
mesh_terms: D000328:Adult; D001755:Blastocyst / Q000528:radiation effects*; D002970:Cleavage Stage, Ovum / Q000528:radiation effects*; D005260:Female; D005307:Fertilization in Vitro / Q000379:methods* / Q000706:statistics & numerical data; D006801:Humans; D007246:Infertility / Q000175:diagnosis* / Q000628:therapy*; D007834:Lasers; D008297:Male; D011247:Pregnancy; D018873:Pregnancy Rate; D011272:Pregnancy, Multiple / Q000706:statistics & numerical data; D011379:Prognosis; D016896:Treatment Outcome; D058989:Vitrification
keywords: IVF; blastocyst cryopreservation; clinical outcomes; laser-assisted hatching; low-grade cleavage-stage embryo; zona pellucida