Clinical pregnancy rates after two different methods of laser-assisted hatching applied to vitrified-warmed day-3 embryos or day-5 blastocysts.

Abstract

Objective: Laser-assisted hatching (LAH) employs two distinct techniques: thinning and breaching. This study aimed to compare the clinical efficacy of combined thinning and breaching versus breaching alone in vitrified-warmed embryo or blastocyst transfer cycles.

Methods: In total, 110 vitrified-warmed day-3 embryo transfer cycles and 50 vitrified-warmed day-5 blastocyst transfer cycles were retrospectively selected. All transfers were performed between 2021 and 2022 at a university-based infertility center. Combined thinning and breaching involved thinning either one-quarter or one-sixth of the zona pellucida circumference combined with breaching at a single point.

Results: In vitrified-warmed day-3 embryo transfer cycles, the 'thinning and breaching' and 'breaching only' groups were similar regarding the median age of the woman (36 years vs. 37 years, respectively), number of embryos transferred (2 vs. 2), and embryo score (89 vs. 31.5). The clinical pregnancy rate (PR) (23.5% vs. 21.1%), embryo implantation rate (IR) (11.4% vs. 11.3%), and clinical miscarriage rate (25% vs. 37.5%) were also comparable between the two LAH groups. In vitrified-warmed day-5 blastocyst transfer cycles, the combination and breaching-only groups were similar in the median age of the woman (36 years vs. 36.5 years, respectively), number of blastocysts transferred (1 vs. 1), and blastocyst score (45 vs. 31.5). The clinical PR (45.5% vs. 42.9%), IR (35.4% vs. 33.3%), and clinical miscarriage rate (20% vs. 33.3%) were also similar between groups.

Conclusion: Breaching alone displayed similar efficacy to combined thinning and breaching in terms of clinical PR, IR, and miscarriage rate. Thus, breaching alone appears sufficient to achieve favorable pregnancy outcomes.