Laser-assisted hatching improves clinical outcomes of vitrified–warmed blastocysts developed from low-grade cleavage-stage embryos: a prospective randomized study

• Published in: Reproductive biomedicine online Vol. 28; no. 5; pp. 582 - 589
• Main Authors: Wan, Cai-Yun, Song, Cheng, Diao, Liang-Hui, Li, Guan-Gui, Bao, Zhong-Jian, Hu, Xiao-Dong, Zhang, Hong-Zhan, Zeng, Yong
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier Ltd 01.05.2014
• Subjects: Adult; Blastocyst - radiation effects; blastocyst cryopreservation; Cleavage Stage, Ovum - radiation effects; clinical outcomes; Female; Fertilization in Vitro - methods; Fertilization in Vitro - statistics & numerical data; Humans; Infertility - diagnosis; Infertility - therapy; IVF; laser-assisted hatching; Lasers; low-grade cleavage-stage embryo; Male; Obstetrics and Gynecology; Pregnancy; Pregnancy Rate; Pregnancy, Multiple - statistics & numerical data; Prognosis; Treatment Outcome; Vitrification; zona pellucida; laser-assisted hatching; IVF; blastocyst cryopreservation; clinical outcomes; zona pellucida; low-grade cleavage-stage embryo
• ISSN: 1472-6483; 1472-6491
• DOI: 10.1016/j.rbmo.2014.01.006

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. How to improve the implantation rate and clinical outcomes of embryo transfers in patients following IVF is a hot issue in current studies of human assisted reproduction technology. In this study, we aimed to evaluate the effects of quarter zona-pellucida opening by laser assisted hatching (QLAH) on the clinical outcomes following the transfer of vitrified–warmed blastocysts developed from low-grade cleavage-stage embryos in patients with all their high-grade and fair-grade cleavage-stage embryos transferred but who had not become pregnant. Our results showed that the implantation and clinical pregnancy rates were significantly increased after QLAH, suggesting that QLAH may serve as a potential approach for effectively utilizing low-grade cleavage-stage embryos, which are often discarded) and increasing the chances of pregnancy in patients undergoing IVF. However, further multicentre studies on a larger scale should be performed.