Doctors use an important blood test called a complete blood count, or CBC for short, to measure the number of each blood cell in your blood sample. If the CBC shows a low number of red blood cells, white blood cells, or platelets, your doctor may look at the cells under a microscope.
In a typical menstrual cycle, estrogen made by the maturing ovarian follicle causes the glands to grow and the endometrium to thicken (partly through an increased blood supply).This thickening of the uterine lining is called the proliferative phase of the menstrual cycle.n a typical menstrual cycle, estrogen made by the maturing ovarian follicle causes the glands to grow and the endometrium to thicken (partly through an increased blood supply).
When menstruation begins, the functional surface layer of the endometrium breaks down and peels off. This is what causes bleeding during a period. Coagulation factors that would normally cause the blood to clot are instead broken down by an enzyme which is released as the endometrium breaks down.hen menstruation begins, the functional surface layer of the endometrium breaks down and peels off. This is what causes bleeding during a period. Coagulation factors that would normally cause the blood to clot are instead broken down by an enzyme which is released as the endometrium breaks down.