Embryo freezing after Assisted Reproduction Procedures: Blastocyst vitrification
What is cryopreservation?
Cryopreservation is used in infertility programs mainly to freeze and store embryos from an assisted reproductive cycle (IVF, ICSI, PICSI).
What is vitrification?
We are currently using the vitrification technique for blastocyst freezing.
Vitrification is an ultra-rapid method to freeze blastocysts instead of the traditional slow freezing process.
By definition; vitrification is the process of converting fluid/matter into a glass-like solid that is free of any crystal formation.
Vitrification of blastocysts yields better post-thaw survival rates and higher pregnancy and live birth rates from frozen embryo transfer cycles.
We started vitrification of blastocysts in late 2007 and have seen an increase in post-thaw embryo survival rates as well as substantially higher pregnancy rates after frozen transfer procedures.
The vitrification technique proves to have an undeniable better success rate regarding the viability of the blastocysts after vitrification and warming, more patients’s for frozen embryo transfers and most importantly a superior success rate.
When do we vitrify?
From experience poor quality day 5 or 6 blastocysts/expanded blastocysts do not survive vitrification and warming.
Therefore only good quality day 5 or 6 blastocysts/expanded blastocysts are vitrified and stored at -196ºC.
Storage in Liquid Nitrogen.
Colour coded Goblets and 
Straws to assist with
Identification.
Indications for Vitrification
- Extremely good quality blastocysts/expanded blastocysts.
- Blastocysts/expanded blastocysts of patients at risk of hyperstimulation syndrome are vitrified, warmed and transferred in a following cycle.
- Poor uterine lining (endometrium), day 5 or 6 blastocysts/expanded blastocysts are vitrified and stored to be transferred in a more favourable cycle.
Shrunken blastocyst after warming Warming blastocyst after 6 hours
of incubation
The blastocysts are warmed on the equivalent of Day 5 in either a natural or controlled cycle and transferred after an incubation period of 4 to 6 hours. Two hours after warming the viability of the blastocysts can be identified. Pregnancy testing is performed 10 to 12 days later.
Risks
Some blastocysts may not survive the freezing process. This is related to the quality of the blastocyst itself.
When reaching the vitrified stage and being stored at -196°C, the blastocysts are relatively safe from further damage. The DNA damage during cryogenic storage has suggested a maximum storage period of 1000 years.
Blastocyst implantation after FET
The embryo implantation process is not different from a fresh cycle.
Pregnancy detection following blastocyst FET is possible with a sensitive blood assay for HCG hormone by 10 to12 days after a fresh or frozen blastocyst transfer.
Statistics
The recovering rate after warming is 98%. Most of the patients scheduled for FET would receive 1 to 2 blastocysts on the day of transfer.
Pregnancy rate for a frozen embryo transfer (FET) is similar to a fresh cycle.
The average clinical pregnancy rate up to date for FET is between 46 and 52%.
Cost:
We charge R3 630.00 for vitrification (blastocyst freezing). There is no storage fee involved for the first three months of storage. Thereafter a minimal fee is charge each day and an account will be send to you every six months. These are subject to change.