Embryos from vitrified vs. fresh oocytes in an oocyte donation program: a comparative morphokinetic analysis

Area of Science:

• Reproductive biology
• Embryology
• Assisted reproductive technology

Background:

• Oocyte cryopreservation, particularly vitrification, is a key technique in assisted reproduction.
• Comparing outcomes from vitrified versus fresh oocytes is crucial for optimizing fertility treatments.

Purpose of the Study:

• To compare the morphokinetic development of human embryos from vitrified oocytes versus fresh oocytes in donation cycles.
• To assess the impact of oocyte vitrification on fertilization, cleavage, blastocyst formation, and clinical outcomes.

Main Methods:

• Retrospective observational study at Embryolab Fertility Clinic.
• Analysis of embryos from 421 vitrified oocytes and 196 fresh oocytes in donation cycles.
• Evaluation of key time parameters, dynamic events, and various reproductive rates using time-lapse technology.

Main Results:

• Vitrified oocytes had a mean survival rate of 92.58%.
• Fertilization rates were significantly lower in the vitrified group (71.92%) compared to the fresh group (80.65%).
• No significant differences were observed in degeneration, cleavage, blastocyst, implantation, or live birth rates between the groups, despite minor variations in early cell cycle progression (CC1 and CC1a).

Conclusions:

• Early embryo development (CC1) shows temporary deviations in vitrified oocytes compared to fresh oocytes.
• These early developmental differences did not significantly affect overall embryo development or clinical outcomes.
• The study suggests that oocyte vitrification is a viable option, though larger sample sizes are needed to confirm the lack of significant impact on clinical results.