Zona thinning with the use of laser: a new approach to assisted hatching in humans.

From 1993 to 1994, in our centre, laser-assisted hatching was performed on 2- to 4-cell stage embryos obtained from in-vitro fertilization (IVF) patients. We treated 376 embryos from 96 patients with repeated IVF failures (two to four attempts) (group A) and 397 embryos from 111 patients undergoing IVF for the first time (group B). Embryos were transferred immediately after the laser treatment. Both groups were compared to control groups (A' and B') whose embryos were transferred with intact zona pellucida (ZP). The resulting clinical pregnancies were 41 in A and 44 in B versus 24 in A' and 23 in B' respectively. The pregnancy rates per patient were 42.7 and 39.6% versus 23.1 and 19% in the control groups (P < or = 0.05), while the implantation rates per embryo were 12.2% in A and 11.8% in B versus 7.3% and 7.1%. These results show that laser zona thinning of human embryos at 48 h after egg retrieval significantly increases the implantation and pregnancy rate (P < or = 0.05).

[1]  W Feichtinger,et al.  Successful clinical application of laser for micromanipulation in an in vitro fertilization program. , 1992, Fertility and sterility.

[2]  S. Ratnam,et al.  Cocultures: a new lead in embryo quality improvement for assisted reproduction. , 1991, Fertility and sterility.

[3]  J W Gordon,et al.  Clinical evaluation of three approaches to micromanipulation-assisted fertilization. , 1990, Fertility and sterility.

[4]  R. Edwards,et al.  Cryopreservation of cleaving embryos and expanded blastocysts in the human: a comparative study. , 1985, Fertility and sterility.

[5]  R. Gardner,et al.  Effect of damage to the zona pellucida on development of preimplantation embryos in the mouse. , 1989, Human reproduction.

[6]  M. Berns,et al.  Opening of the mouse zona pellucida by laser without a micromanipulator. , 1993, Human reproduction.

[7]  D Mitchell,et al.  Partial zona dissection of human oocytes when failure of zona pellucida penetration is anticipated. , 1989, Human reproduction.

[8]  C. Versaci,et al.  Andrology: Seventeen live births after the use of an erbium-yytrium aluminium garnet laser in the treatment of male factor infertility , 1994 .

[9]  H E Malter,et al.  Blastocyst formation and hatching in vitro following zona drilling of mouse and human embryos. , 1989, Gamete research.

[10]  Z. Rosenwaks,et al.  Mechanisms and factors of early pregnancy wastage in in vitro fertilization-embryo transfer patients. , 1988, Fertility and sterility.

[11]  G. Wright,et al.  Partial dissection of the zona pellucida of frozen-thawed human embryos may enhance blastocyst hatching, implantation, and pregnancy rates. , 1991, American journal of obstetrics and gynecology.

[12]  K. Schütze,et al.  Zona drilling and sperm insertion with combined laser microbeam and optical tweezers. , 1994, Fertility and sterility.

[13]  I. Sargent,et al.  The human blastocyst: morphology and human chorionic gonadotrophin secretion in vitro. , 1991, Human reproduction.

[14]  S. Ratnam,et al.  Co-cultures: their relevance to assisted reproduction. , 1990, Human reproduction.

[15]  W Feichtinger,et al.  Use of lasers in assisted fertilization and hatching. , 1994, Human reproduction.

[16]  M. Tucker,et al.  Cruciate thinning of the zona pellucida for more successful enhancement of blastocyst hatching in the mouse. , 1992, Human reproduction.

[17]  J. Gordon,et al.  A new mouse model for embryos with a hatching deficiency and its use to elucidate the mechanism of blastocyst hatching. , 1993, Fertility and sterility.

[18]  J. Gordon,et al.  Restoration of normal implantation rates in mouse embryos with a hatching impairment by use of a new method of assisted hatching. , 1993, Fertility and sterility.

[19]  H Malter,et al.  Impairment of the hatching process following IVF in the human and improvement of implantation by assisting hatching using micromanipulation. , 1990, Human reproduction.

[20]  Peter Fuhrberg,et al.  Photoablation of oocyte zona pellucida by erbium-yag laser for in-vitro fertilisation in severe male infertility , 1992, The Lancet.

[21]  Z. Rosenwaks,et al.  Implantation enhancement by selective assisted hatching using zona drilling of human embryos with poor prognosis. , 1992, Human reproduction.

[22]  S. Lindenberg,et al.  A comparative study of attachment of human, bovine and mouse blastocysts to uterine epithelial monolayer. , 1989, Human reproduction.

[23]  N. Laufer,et al.  Fertilization of human oocytes by sperm from infertile males after zona pellucida drilling. , 1988, Fertility and sterility.