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Updated: Aug 6, 2026
Human Blastocyst Biopsy and Vitrification
Published on: July 26, 2019
Association between laser-assisted hatching and subsequent blastocyst development in fresh day 3 cleavage-stage
Lixia Miao1, Lian Zou1, Min Wang1
1Wuxi Maternity and Child Health Care Hospital, Affiliated Women's Hospital of Jiangnan University, Wuxi, Jiangsu, China.
Background:
To investigate the association between laser-assisted hatching (LAH) and blastocyst developmental outcomes of day 3 (D3) cleavage-stage embryos in fresh IVF cycles, using Propensity Score Matching (PSM), Generalized Estimating Equation (GEE) analysis, and Time-sensitivity analyses.
Methods:
The clinical data of 4365 couples who received in vitro fertilization (IVF) treatment at Wuxi Maternal and Child Health Hospital from January 2018 to December 2023 were retrospectively analyzed. The patients were divided into the LAH (n=3193) and the non-LAH (n=1172). To control potential confounding factors, the baseline characteristics of the two groups were balanced by 1:1 Propensity Score Matching (PSM), and 999 couples were included in each group. The Generalized Estimating Equation (GEE) was further applied to correct the multi-factor interference and evaluate the independent effect of LAH on blastocyst development. In this study, the research cohort was restricted within ±6-month, ± 12-month, and ±24-month time windows, and time-sensitivity analyses were performed to assess potential time-related confounding bias.
Results:
After propensity score matching, LAH was associated with a higher transferable blastocyst formation rate, especially in grade II-IV embryos (P < 0.001). GEE analysis confirmed this association, whereas no significant improvement in high-quality blastocyst formation was observed. Sensitivity analyses using ±6-, ± 12-, and ±24-month windows showed no significant difference in overall blastocyst formation. For transferable blastocyst formation, no association was found in the ±6-month model, while positive associations were observed in the ±12-month model (adjusted rate difference: 4.62%, 95% CI: 1.30%-7.95%, P = 0.006) and ±24-month model (6.69%, 95% CI: 4.46%-8.92%, P < 0.001). However, after adjustment for calendar time, this association became non-significant (P = 0.573), suggesting possible time-related confounding.
Conclusion:
LAH may improve transferable blastocyst formation in low-grade day 3 cleavage-stage embryos under specific analytical conditions, but the findings were heterogeneous across sensitivity analyses. Because implantation, pregnancy, live birth, neonatal safety, and long-term offspring outcomes were not assessed, these results should be considered hypothesis-generating and require confirmation in multicenter prospective randomized trials.
