After egg retrieval, the fertilized eggs are stored in an embryoscope. An embryoscope is an incubator that imitates of the conditions in a woman’s uterus. The laboratory closely monitors the development of the fertilized eggs via video surveillance.
Upon successful fertilization, the egg begins to divide. On day 2, the egg has cleaved into the stage called embryo. The embryo can be put back in the uterus on days 2 – 3.
A fertilized egg that is not laid back on days 2-3 can continue its cell cleavages in the embryoscope in the laboratory. We call this process blastocyst culture. If the egg continues its development and continues to divide, on day 5 it will reach the stage called blastocyst. A blastocyst has cleaved into 60 – 100 cells. The blastocyst is transferred into your uterus on day 5.
A blastocyst has a higher chance of leading to a pregnancy that a 4-cell embryo on day 2. We recommend blastocyst culture if all fertilized eggs divide really nicely and we have a hard time choosing which embryo is best for transfer.
If the laboratory on day 2-3 can say which egg is best for transfer, blastocyst culture is not necessary.
The excess embryos, which are not transferred on days 2 – 3, are either frozen on days 2-3, or they continue their development in a conventional incubator and will be frozen on day 5 or 6 if they turn into blastocysts. There will not be any surveillance of the embryos during the coming days.
Blastocyst culture costs 6000 DKK (sept. 2020, subject to price changes) per IVF treatment (regardless of number of eggs). Blastocyst culture is an additional service, whether you buy one treatment or a contract with 3 IVF treatments.
When choosing blastocyst culture, you pay for a place in the embryoscope where the fertilized eggs are cultured further and that the laboratory technicians closely follow the development of the embryo day by day. The laboratory technicians review the development of the embryo every morning and make sure that any wrong cleavages are registered.
When the embryos reach the blastocyst stage, the laboratory technician will give the embryos a new score. The best blastocyst is laid back into the uterus and excess blastocysts are frozen, if they fulfill the quality score. If you get more than 1 blastocyst frozen, the score will help us select the right blastocyst for a future transfer with one of the frozen blastocysts.
Assisted hatching (AHA) is performed on the blastocyst before embryo transfer into the uterus. Assisted hatching is included in the price of blastocyst culture (sept. 2020, subject to changes). In assisted hatching, a small hole is made in the “shell” of the egg – also called zona pellucida. This is done with a laser. The small hole in the shell of the egg helps the blastocyst to come out of the shell (to hatch) in order to implant into the uterine lining.