Relevance of assisted hatching in an oocyte donation programme using egg cryobanking: a prospective randomised study.

OBJECTIVE The objective of this prospective randomised study was to evaluate if there is an improvement in clinical outcomes when assisted hatching (AH) is performed in embryos derived from vitrified/warmed oocytes in an ovum donation programme using egg cryobanking. STUDY DESIGN Sixty oocyte recipients in a donation programme using egg cryobanking were randomly allocated to the assisted hatched (AH, n=30) or control group (n=30). The pregnancy and implantation rates were compared between the groups. RESULTS A total of 288 vitrified oocytes were warmed for the 60 recipients. Of the 288 vitrified oocytes, 94.8% survived. All surviving oocytes were sperm injected, and 83.5% underwent fertilisation. There were 172 good-quality embryos selected for transfer. The total pregnancy rate was 40%. The pregnancy rate did not differ between the AH and control groups (43.3% and 33.3%, respectively, p=0.1967), but AH resulted in a higher implantation rate (31.6% vs. 18.4%, p=0.0206). CONCLUSION Our study demonstrates the effectiveness of AH in embryos derived from warmed oocytes. Our results also suggest that oocyte cryopreservation can be considered as a tool for providing highly successful outcomes in an egg donor programme.