STEP 5 : Fertilisation
In this step, every mature egg is given a single sperm. There are different procedures the laboratory can use to fertilise the collected eggs. The decision of which one (or which combination) of these will be used by the embryologist is based on the past history and the present status of the gametes. All details are explained to patients in their appointment with the embryologist prior to the cycle. One of these procedures is intracytoplasmic sperm injection (ICSI) and another is physiologically selected intracytoplasmic sperm injection (P-ICSI). The semen sample is processed in the andrology laboratory and evaluated prior to its use. After the sperm is injected into the egg, the egg is cultured in an incubator and checked for fertilitisation after 16 to 18 hours. Once the egg is fertilised it’s called an embryo, which is cultured in the embryology laboratory for three to five days.