American women are taught, and doctors generally assume, that the “normal” pattern of the reproductive cycle is to menstruate every 28 days, plus or minus a few. Of course certain things, such as pregnancy, can interrupt that cycle but the general assumption has been that on average women bleed thirteen times a year for their entire reproductive life. Indeed, the 28 day oral contraceptive regimen was intentionally designed to mimic a “normal” reproductive cycle.
The Sahel region of Mali borders the Sahara desert and shares many of it's characteristics, especially during the dry season. It is also the home of the Dogon people, a farming tribe whose beliefs and customs have changed very little over the past millennium. The Dogon women use no contraception and from menarche to menopause, confine themselves to designated huts on the periphery of the village when menstruating. This made them an excellent population for Dr. Beverly Strassmann, a biological anthropologist who studies the evolutionary origins and consequences of menstruation. Living among the Dogon for two and a half years afforded Dr. Strassmann the opportunity to establish what the actual pattern of an unfettered menstrual history looked like.
What she found, as expected, was that women not subject to artificial manipulation of menstrual cycles have many fewer of them, a result of more pregnancies and more years of nursing. Dogon women menstruate seven times a year on average, between menarche and age nineteen. From twenty to thirty four, prime reproductive years, they average one menstrual cycle per year, while from thirty five through menopause the average increases to four yearly. In their entire reproductive lives few Dogon women reach one hundred total menstruation cycles. Compare that with modern western women who may menstruate over four hundred times in their lives.
Of course modern western women don't have an average of eight to nine pregnancies and spend around twenty years of their lives breast feeding. But that is precisely the point. One hundred life time cycles is normal; four hundred is not. Excess menstrual cycles are an artifact of birth control, and not just oral contraceptives which were designed to produce bleeding every twenty eight days to appear as natural cycles (and thus possibly be a form of birth control acceptable to the Pope), but any form of birth control. They all have the same unintended and, as we now know, detrimental side effect of hundreds of excess menstrual cycles.
Detrimental? Most assuredly. Each menstrual cycle sets in motion massive increases in the rate of cell division in the breast, endometrium, and ovary, and is accompanied by large shifts in hormone balances, changes in fat and water stores and metabolic activity. Both pregnancy and breast feeding significantly decrease the risk of ovarian, endometrial, and breast cancer. Oral contraceptives also decrease the risk of ovarian cancer even though they do not decrease the number of bleeding cycles in typical use. Why? Probably because they decrease the number of ovulations which dramatically increases the number of lifetime cell divisions. Oral contraceptives, at least in current use, may also increase the risk of some cancers. For more info see Hormones and Cancer – the reproductive years.
If you don't want to get pregnant but still don't want to have all those bleeding cycles, what to do? As noted above, hormonal contraceptive pills were specifically designed to create the illusion of normal menstrual cycles. They aren't normal menstrual cycles. They're only supposed to look like them. For one thing as already noted, there is no ovulation, only a monthly build up and sloughing off of endometrium. It looks like a normal cycle but is anything but. Hormones are still suppressing ovulation but are manipulated to intentionally produce an unnecessary and non-functional bleed that looks like a normal period.
For more on the reasons and the history behind the bleeding facade see The Pope, the Pill, and the Problem.
So how to stop the lifetime excess of cycles while still controlling the number of offspring you choose to bring into the world? The best option currently is still oral hormones, dosed so as to avoid creating bleeding cycles.
Most currently formulated oral contraceptive pills have either twenty one or twenty four "active" pills and four or seven "placebo" pills. The so called "active" pills contain progesterone (along with estrogen). Progesterone supports and stabilizes the endometrial lining of your uterus. The "placebo" pills may be actual placebos or more often contain only estrogen but no progesterone. Withdrawing the progesterone causes the lining to slough off and you bleed.
Avoiding the bleed is accomplished by continuously taking progesterone. Essentially it requires taking a low dose oral combined estrogen and progesterone pill every day, just as one would take current oral contraceptive pills. The difference is you don't take the placebo or estrogen-only pills, the four or seven (depending on the brand) pills at the end of each pack. Instead you skip to a new pack and continue with a pill that contains progesterone and you do not bleed at all unless and until you want to!
It's called continuous dose oral contraception and, in theory, it's that simple. In practice it is a bit more nuanced but it can be done, and many oral contraceptive users find it much more convenient not to have an artificially induced bleed every month. You can get more information about it on the Contraception page.