The third step in the IVF procedure is the retrieval of the eggs to be fertilized. This step begins with a trigger shot, which is an injection to stimulate the maturation of the follicles and to stimulate ovulation. This injection is given at a precise time that is determined by the close monitoring of follicle growth and estrogen levels.
The trigger shot
The doctor will monitor follicle growth until the majority of the follicles are around 20mm in size. This is the optimum follicle size for mature eggs to be developed. Estrogen levels are also closely monitored during this stage as this helps determine the proper medication for the doctor to use for the trigger shot. The trigger shot causes the eggs to undergo final maturation so that they will be ready to harvest.
Egg retrieval
About 36 hours after the trigger shot is administered the egg retrieval will occur. Timing is very important during this stage as the eggs must be harvested before ovulation begins and the eggs will be lost. This procedure usually takes about twenty to thirty minutes to perform and it is typically performed under sedation.
A needle of the appropriate size, (that was determined during the practice run) will be inserted into the ovary and the follicle fluid and egg will be withdrawn. The eggs will then be fertilized by sperm from the male partner or by donor sperm.