Expansion and herniation: evaluation of the best pregnancy rate predictor after quarter laser assisted hatching in frozen blastocyst transfers.

Abstract

ObjectiveTo assess the recovery of thawed blastocysts submitted to quarter laser assisted hatching and examine potential correlations between the procedure and pregnancy rates.MethodsThis cross-sectional study included only single-blastocyst transfers performed from July 2017 to December 2018. A total of 765 blastocysts were thawed and immediately submitted to quarter laser assisted hatching in the zona pellucida; they were subsequently incubated for three hours until transfer time, at which time they were examined for collapse or expansion; expanded blastocysts were further evaluated for herniation. The Chi-square test was used in statistical analysis.Results627 blastocysts expanded (81.9%) and yielded a pregnancy rate of 40% (251/627). 138 blastocysts collapsed after thawing (18.0%) and yielded a pregnancy rate of 25.4% (35/138) (p=0.001). Additional analysis of the subgroup of expanded blastocysts revealed that the 385 herniated blastocysts (61.4%) yielded a pregnancy rate of 43.9% (169/385). The remaining 242 non-herniated blastocysts (38.6%) yielded a pregnancy rate of 33.9% (82/242) (p=0.013). Statistical significance was attributed to events with a p<0.05.ConclusionQuarter laser assisted hatching is a safe, valid, and relatively easy-to-use procedure for thawed blastocysts. Blastocysts that expanded and herniated after quarter laser assisted hatching presented statistically superior results.