There is some compelling evidence that the human female is not biologically designed to have a period each month. In hunter-gatherer societies, the female would become pregnant, give birth, and then nurse for considerably longer than modern females do. The lactation would (mostly) prevent her from having a period again until the child was weened, probably at age two or three. So, according to this logic, a woman could only need to have a period a few times over the course of several years.
If this theory pans out, that would mean that being on the pill actually allows the body to menstruate more according to its biological design, and that frequent menstruation is actually the aberration.
