Intracytoplasmic sperm injection (ICSI) involves extracting eggs and fertilizing them using a special micropipette. Embryologists inject sperm into each egg (directly into the cytoplasm) in the laboratory. Embryo transfer takes place 3-5 days later. Ovarian stimulation (hormonal treatment) is needed before extracting the oocytes. Controlled stimulation means we can collect more mature oocytes.