Sometimes, a small sample of tissue may be taken with small tools inserted through the vagina during a transvaginal ultrasound. In all three types of pelvic ultrasound, the transducer sends the reflected sound waves to a computer, which makes them into a picture that is shown on a video screen.
So the number of egg-containing follicles remaining in the ovary undergoes a steady decline from an average of 400,000 eggs at age eighteen to an average of 25,000 eggs by age thirty-seven. After age thirtyseven or thirty-eight, there is then a very dramatic acceleration of the monthly decline of remaining eggs.
In women with a regular cycle, normal ovary functioning releases one egg about every 25â28 days. Although the average time between periods varies depending on the woman, especially during puberty and the perimenopause periods, most women will have their periods once monthly when theyâre in good health.