Laser-assisted hatching in assisted reproduction

Aim. The use of a 1.48 mu m diode laser for assisted hatching was investiga ted in animal experimentation. Laser assisted hatching was offered to patie nts with advanced maternal age to evaluate a possible benefit. Methods. Using the Fertilase(R) system we investigated the impact of openin gs with different size in the zona of mouse embryos on the hatching process , as well as that of two openings. Laser-drilling was performed at the blas tocyst stage to look for differences in timing and efficacy of hatching, Th e possible benefit of assisted hatching was studied in 24 couples with adva nced maternal age (38.8 +/- 2.1 years) and compared to a control group (37. 8 +/- 2.5 years) treated in the same time period but without assisted hatch ing. Results. A certain diameter of a laser drilled opening in the zona pellucid a is necessary for efficient hatching. When two openings are present in the zona, the embryo will use both openings for hatching and subsequently beco me trapped. Laser-drilling at the expanded blastocyst stage causes an immed iate collapse of treated blastocysts and the onset of hatching is retarded. Assisted hatching in 24 patients with advanced maternal age resulted in a significant increase (p < 0.01) in the implantation rate when compared to 2 4 untreated patients. Conclusion. The use of a 1.48 mu m diode laser to drill an opening into the zona pellucida provides a good alternate to conventionally applied techniq ues. The procedure is efficient and safe as long as it is applied properly. In a human in vitro fertilization program, selected patients will have a b enefit form assisted hatching.