In a normal ovulation cycle one egg matures per month In an ivf cycle the goal is to have several eggs mature as this will increase your success with treatment. In the ovarian stimulation phase of the IVF cycle injectable medications are used for approximately 8 to 14 days to stimulate follicular development. Regular ultrasound scans are done to measures the growth of each follicle (that contain egg) and thickness of uterine lining, both of which should be increasing as you take injectable medications.