Embryo ploidy in vitrified versus fresh oocytes: Is there a difference?

Area of Science:

• Reproductive Medicine
• Genetics
• Embryology

Background:

• Oocyte cryopreservation is a key component of assisted reproductive technologies.
• Preimplantation genetic testing for aneuploidy (PGT-A) assesses embryo chromosomal status.
• Comparing outcomes between vitrified and fresh oocytes is crucial for optimizing fertility treatments.

Purpose of the Study:

• To compare embryo ploidy rates in patients undergoing PGT-A using vitrified oocytes versus fresh oocytes.
• To evaluate the impact of oocyte vitrification and warming on chromosomal competence.
• To assess the efficacy of PGT-A following oocyte cryopreservation.

Main Methods:

• A retrospective cohort study compared patients undergoing their first IVF cycle with vitrified oocytes to age-matched controls using fresh oocytes.
• All patients underwent trophectoderm biopsy for PGT-A.
• The study matched 117 patients with vitrified oocytes to 351 controls with fresh oocytes.

Main Results:

• No statistically significant differences were observed in the rates of euploidy (40.1% vs. 41.6%), mosaicism (15.7% vs. 12.0%), or aneuploidy (44.3% vs. 46.4%) between the vitrified and fresh oocyte groups.
• Similar numbers of mature oocytes, fertilized oocytes, and blastocysts were obtained per patient in both groups.
• The average patient age was 36.9 years, with a median interval of 38 months between oocyte vitrification and warming.

Conclusions:

• Oocyte vitrification followed by warming, fertilization, and trophectoderm biopsy for PGT-A is not associated with adverse effects on embryo chromosomal competence.
• Cryopreserved oocytes maintain their potential for producing chromosomally normal embryos when assessed via PGT-A.
• These findings support the use of oocyte vitrification as a viable option for fertility preservation and treatment.