STEP 5: EGG FERTILIZATION AND EMBRYO DEVELOPMENT
Semen will first be “washed” and then concentrated. Several hours after egg extraction, the sperm will be connected to the eggs. Eggs with sperm in special dishes are placed in thermo-cabinets.
The next morning the embryologist will assess how many eggs have fertilized. Unfortunately, not all eggs become fertilized. If the sperm quality is normal, we expect that 70-80% of eggs will fertilize. The doctor or embryologist will contact you and inform about the results and future strategy. In the case of blastocyst culturing, fertilized egg continues to cultivate in an incubator for 24-48 and up to 96 hours.
If the sperm quality is poor (low concentration and motility), then your doctor will offer egg fertilization by ICSI (intracytoplasmic sperm injection) method – with a special needle one spermatozoa is injected into the egg. This procedure is performed under microscope control and requires a highly skilled embryologist. This does not change the stimulation protocol steps.