Laser-assisted hatching in lower grade cleavage stage embryos improves blastocyst formation: results from a retrospective study

Abstract

Background Laser-assisted hatching (LAH) has been widely applied to facilitate blastocyst hatching in IVF-ET treatment, however, the effect of LAH on subsequent development and clinical outcomes of the lower grade cleavage stage embryos (LGCE) remains unknown. Our study aimed at evaluating the effect of LAH on blastocyst formation and the clinical pregnancy outcomes of LGCE embryos after transfer. Methods A total of 608 cycles of IVF/ICSI treatment from November 2017 to September 2019 were included in our study as follows: 296 in the LAH group and 312 in the N-LAH group. The total blastocyst rate, usable blastocyst rate, good-grade blastocyst rate and clinical pregnancy rate were statistically compared between the two groups. Results The total blastocyst rate (50.7% vs 40.2%, P < 0.001), usable blastocyst rate (31.0% vs 18.6%, P < 0.001) were significantly higher in the LAH group than those in the N-LAH group. After analysis of generalized estimating equations, LAH was positively correlated with the blastocyst rate (B = 0.201, OR 95% CI = 1.074–1.393, P = 0.002), usable blastocyst rate (B = 0.478, OR 95% CI = 1.331–1.955, P < 0.001). However, the clinical pregnancy rate after blastocyst transfer did not differ between LAH group and N-LAH group (49.4% vs 40.0%, P > 0.05, respectively). Conclusions A higher proportion of total blastocysts and usable blastocysts can be obtained by LAH in LGCE, which may be beneficial to the outcome of the IVF/ICSI-ET cycle.

Thinning or Opening: A Randomized Sibling-Embryo Pilot Trial on the Efficacy of Two Laser-Assisted Hatching Modes During the Extended Culture of Highly Fragmented Cleavage Embryos

“…Our results showed that the LAT treatment have an equivalent value to LAO in terms of total, viable, top-quality and hatched blastocyst formation, as well as the clinical outcomes after blastocyst transfer. Both LAO and LAT have better blastulation outcomes compared to those of non-treated low-graded embryos, as reported in our previous study ( 3 ).…”

“…Finally, a total of 166 day-3 embryos developed into blastocyst stage (52.70%), of which 97 were viable blastocysts (30.79%), and 42 top-quality ones (13.33%). The blastulation outcomes here were obviously higher than those for untreated embryos as reported in our previous study (40.2%, 18.6% and 9.2%, respectively) under the same cultural conditions ( 3 ).…”

“…We recruited the participants from the infertile couples who underwent their first IVF-ET cycles. The inclusion criteria were defined as follows ( 1 ): female partner aged <40 years ( 2 ); those couples with more than 2 highly fragmented day-3 cleavage embryos (specified as embryos originating from 2PN zygote, with fragment rate >25% and at least 4 blastomeres) ( 3 ); receiving extended in vitro culture. The exclusion criteria were ( 1 ) abnormal karyotypes of any partner ( 2 ); embryos originating from assisted oocyte activating or in vitro maturation procedure ( 3 ); familial infertility of any partner.…”

“…All these findings encourage the addition of LAH operation during the extended culture process for untransferable cleavage embryos to promote the utilization of low-graded embryos, especially for the fragmented ones. Our previous report has identified an improved blastocyst outcome when a LAH operation was performed in low-graded cleavage embryos at day 4 ( 3 ). This is consistent with a previous study conducted on fragmented embryos using a AH method with acidic tyrode’s solution ( 13 ).…”

“…Embryonic fragmentation, one of the most common morphological defections in cleavage embryos, is considered as a dominant impairment to oocyte utilization during IVF procedure, and unanimously as a major stubborn challenge faced by embryologists ( 1 , 2 ). Despite poor developing potential and inappropriateness for direct transfer, heavily fragmented cleavage embryos are still subject to extended in vitro culture in practice, with the purpose of vitality discrimination ( 3 , 4 ). Currently nevertheless, the blastulation of the fragmented embryos remains really inferior, even though various means have been attempted, such as mechanical aspiration of the cellular debris and addition of some cytokines such as granulocyte colony-stimulating factor (G-CSF) ( 5 , 6 ).…”