About 34 to 36 hours after you receive the hCG shot, the egg retrieval will take place. It's normal to be nervous about the procedure, but most women go through it without much trouble or pain.
Before the retrieval, an anesthesiologist will give you some medication intravenously to help you feel relaxed and pain free. Usually, a light sedative is used, which will make you "sleep" through the procedure. This isn't the same as general anesthesia, which is used during surgery. Side effects and complications are less common.
Once the medications take their effect, your doctor will use a transvaginal ultrasound to guide a needle through the back wall of your vagina, up to your ovaries. She will then use the needle to aspirate the follicle, or gently suck the fluid and oocyte from the follicle in to the needle. There is one oocyte per follicle. These oocytes will be transferred to the embryology lab for fertilization.
The number of oocytes retrieved varies but can usually be estimated before retrieval via ultrasound. The average number of oocytes is 8 to 15, with more than 95% of patients having at least one oocyte retrieved.
After the retrieval procedure, you'll be kept for a few hours to make sure all is well. Light spotting is common, as well as lower abdominal cramping, but most feel better in a day or so after the procedure. You'll also be told to watch for signs of ovarian hyperstimulation syndrome, a side effect from fertility drug use during IVF treatment in 10% of patients.