Embryo survival after vitrification and warming is one of the key quality indicators for an IVF laboratory’s cryogenic programme. The data from UK clinics shows consistently high survival rates for vitrified embryos across the sector, though with meaningful variation between individual clinics.
The average survival rate for vitrified embryos across UK clinics is consistently above 85 percent, with well-performing laboratories achieving survival rates of 90 to 95 percent or higher. The HFEA defines survival as the proportion of vitrified embryos that survive the warming process in a sufficiently intact state to be suitable for transfer or further culture.
The factors that drive variation between clinics include:
Laboratory environment control. Precise control of temperature, CO2 concentration, humidity, and volatile organic compound levels during vitrification and warming procedures affects outcomes.
Operator technique. Vitrification is a skilled procedure where timing, cryoprotectant loading accuracy, and handling gentleness all contribute to outcomes. Consistent operator training and competency assessment reduces variability.
Equipment quality. The vitrification workstation, carrier devices, and the quality of cryoprotectant solutions used all affect survival rates. Validated, well-maintained equipment produces more consistent results.
Embryo developmental stage at vitrification. Blastocysts at day 5 or 6 generally tolerate vitrification better than earlier stage embryos.
Cryolab supplies vitrification equipment for UK IVF laboratories, with consultation on protocol optimisation. Visit cryolab.co.uk“>Cryolab
