1. Hormone stimulation
The chance of a successful result with IVF is significantly increased if several eggs can be ripened at the same time (usually done with hormone stimulation). If this is no longer possible or desirable (advance age, limited egg reserves, sensitivity to hormones) IVF cycles can also be performed with one or a few eggs (“mild stimulation IVF”).
2. Retrieving and preparing the eggs
When the eggs are ripe, the doctor removes them under ultrasound guidance through a fine needle that is advanced into the ovary. During the egg retrieval process, fluid is aspirated from the follicles. This procedure usually only takes a few minutes. The woman can have a painkiller and a mild sedative prior to the procedure. The eggs that are retrieved are then prepared for fertilisation in the laboratory.
The sperm cells from the sperm sample are washed in the laboratory. During this procedure, the motile sperm cells are separated from the non-motile and dead cells. If sperm cells are not found in the ejaculate, material obtained during testicular sperm extraction (TESE) can be used. If the partner has no sperm cells that can be fertilised, cryopreserved sperm from a sperm bank (donor sperm) can be used.
4. Fusion of the egg and sperm cells in the test tube
The washed sperm cells and the woman’s egg are fused in a test tube. They are cultured in a special nutrient solution. The sperm cells should fertilise the eggs independently and without further help. The day after egg retrieval, a check is done to see that the eggs were fertilised. The fertilised eggs develop into embryos that are stored in an incubator for up to five days.