title: Laser-assisted hatching of cryopreserved-thawed embryos by thinning one quarter of the zona.
abstract: Laser-assisted hatching is little documented in the literature regarding its efficacy in cryopreserved-thawed (CT) embryo transfer cycles. The aim of the present study was to evaluate in a randomized manner the efficacy of thinning one quarter of the zona pellucida of CT embryos to a depth of 50-80% of the original thickness, via laser treatment (the qLZT-AH procedure), in improving implantation and pregnancy rates. Two populations were studied: population I, patients who had all their supernumerary embryos cryopreserved, regardless of their morphology, and population II, patients at risk of ovarian hyperstimulation syndrome who had all their embryos cryopreserved. Artificial and natural protocols were used for the embryo transfers. A total of 350 laser-thinned CT embryos were compared with 352 intact zona embryos. No difference in implantation or pregnancy rate was found after using qLZT-AH in either population. These findings suggest that qLZT-AH should not be routinely performed in cryopreserved embryo programmes.
authors.affiliation: Centre for Human Reproduction Prof Franco Junior, Av. Prof. João Fiusa 689-CEP 14025-310, Ribeirão Preto, SP-Brazil. petersenclaudia@crh.com.br
authors.forename: Claudia Guilhermino
authors.initials: CG
authors.lastname: Petersen
authors.forename: Ana Lucia
authors.initials: AL
authors.lastname: Mauri
authors.forename: Ricardo Luiz Razera
authors.initials: RL
authors.lastname: Baruffi
authors.forename: João Batista Alcântara
authors.initials: JB
authors.lastname: Oliveira
authors.forename: Valeria
authors.initials: V
authors.lastname: Felipe
authors.forename: Fabiana Cagnoto
authors.initials: FC
authors.lastname: Massaro
authors.forename: Jose Gonçalves
authors.initials: JG
authors.lastname: Franco
mesh_terms: D000328:Adult; D015925:Cryopreservation / Q000379:methods; D010064:Embryo Implantation; D004624:Embryo Transfer; D005260:Female; D006801:Humans; D053685:Laser Therapy; D011247:Pregnancy; D020554:Sperm Injections, Intracytoplasmic / Q000379:methods; D015044:Zona Pellucida / Q000648:ultrastructure*