How Does an Embryo Develop in an IVF Lab?
What the process for embryo development?
You may have already learned a little bit about IVF but, embryo development is really an amazing process. What happens is when eggs are retrieved, one sperm is injected into the egg very carefully through a process called intracytoplasmic sperm injection. That one cell egg is then put in the incubator and left there overnight. At a set time period later the incubator is opened up and those injected eggs are then analyzed underneath a microscope to see evidence that the egg is fertilized, it's really quite magical. In the laboratory, we have embryologists, who are really high-tech dream makers, who not only control the temperature and humidity and oxygen in the incubators. But, they also look after the embryos every day. The day after fertilization when we look at an embryo you have a one-cell structure that has two nuclei. Every cell in your body has one nucleus but on this one special day of your development you had two new nuclei and that's how you document fertilization. You can see evidence of this when you can the male and female pronuclei begin to merge into a single nucleus. That one-cell embryo, which is a zygote, then goes from 1 cell to 2 cells to 4 cells to 8 cells to 16 to 32. Right around the 32 to 64 stage, a little ball of cells that are going to become the embryo is defined. This is also when some cells are going to become the placenta are defined. When the embryo is around 64 to 120 cells it begins to blossoms into a flower. By this we mean there is the inner cell mass, the part that makes the baby, and the outer cell mass, the part that makes the placenta. This is how you know the blastocyst development was successful.