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.
Which ovary produces the egg each month is random. It is usually a short-lived discomfort and is best ignored if possible. As far as the clots go, the size of these really depends on the rate of blood loss from the lining of the uterus, which is shed during a period and is the cause of the bleeding.