PESA is a laboratory-based procedure, meticulously executed to optimize fertilization. The process involves selecting a single sperm with the aid of a fine glass needle and directly injecting it into the egg’s cytoplasm. This method offers a higher chance of fertilization compared to traditional IVF, where multiple sperm are required to achieve fertilization. Stimulation of the ovaries is essential to ensure egg maturation, and this is achieved by using medications, similar to the IVF process.

Once the eggs have matured, they are retrieved through a procedure known as Follicular Puncture, conducted in the laboratory where matured follicles are collected. The best quality sperm is carefully selected, and the ICSI procedure is performed. Following fertilization, the embryos are cultured in the laboratory for 3 to 5 days. Subsequently, the fertilized eggs are transferred back into the uterus with a cannula, allowing the embryo to implant against the uterine lining for further development. Any remaining embryos can be vitrified for use in later cycles, eliminating the need for ovarian stimulation.