EC Gynaecology

Objective: Assisted hatching (AH) is the disruption of the zona pellucida; a technique used to improve implantation and communication between blastocyst and endometrium. AH is widely utilized in poor prognosis patients or when pre-implantation genetic testing is planned. Our retrospective cohort study aims to determine if AH of early blastocysts improves pregnancy outcomes specifically in the setting of delayed embryo development at fresh embryo transfers.

Design: Retrospective cohort study was conducted at an academic IVF center. A total of 71 fresh Day 5 early blastocyst transfers were analyzed from the year 2014 to 2021. Among with or without AH group, pregnancy outcome and implantation rate were compared.

Results: The result showed that AH significantly improved implantation rate (AH 36.5% vs control 9.4%, p = 0.0005), clinical pregnancy rate (AH 54.3% vs control 16.7%, p = 0.0012), and even live birth rate (AH 40.0% vs control 13.9%, p = 0.0166).

Conclusion: Our study supports that AH enhances the implantation potential as well as live birth outcomes of Day 5 fresh embryo transfers and should be considered, especially in patients with delayed blastocyst development. AH in early blastocysts can improve pregnancy outcomes for fresh cycle transfers likely by enhancing the interaction between herniated trophectoderm via AH and endometrial epithelium within the window of implantation.

 Keywords: Assisted Hatching; Fresh Embryo Transfer; In-Vitro Fertilization; Pregnancy Outcomes

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