Menstrual Suppression vs. Continuous Use
Good review article on new-ish birth control methods, emergency contraception, and the IUD. Since continuous contraception is mentioned, let's use this opportunity to look at the difference between menstrual suppression (deals with the real menstrual period) and continuous use (deals with the fake period).
Menses (Real period)
Each month, under the influence of hormones, cyclical changes take place in the ovary and the uterus. This is the monthly cycle. For the purpose of our discussion, we can artificially divide this monthly cycle into an ovarian cycle and an uterine one. Since we're talking about the menstrual period, we're only concerned with the uterine cycle; namely the monthly changes undergone by the lining of the uterine cavity (endometrium).
(Functional layer sheds; basal layer doesn't)
In the beginning of the uterine cycle, the lining is thin. It builds-up gradually during the month, reaches a maximal thickness and then, if there's no pregnancy, most of this thickness is shed, in the form of menstrual bleeding. Then the cycle starts anew.
As you can see, the menstrual period (menses, the real period) is just a small part of the uterine cycle. And, contrary to what you might've been told, the period is not so much a sign of the past (your body failed to become pregnant), as it is a sign of the future (your body is ready and able to sustain a pregnancy). How come?
Briefly, on a cellular level, a fertilized egg (egg + sperm) has a couple of unique characteristics: it has foreign genetical material (the sperm's DNA from the male), and, when it implants, it uses techniques similar to those used by tumor cells. [Implantation is the burrowing of the fertilized egg into the lining of the uterus.]
Inside<--invading fertilized egg<--uterine cavity
So, the uterus has to be able to provide a growing, nourishing environment to something it views as a foreign invader. This poses a problem: normally, the body has mechanisms that fight both foreign bodies (think organ transplant rejection), and tumor cells (the body tries to limit the growth of cancer cells). The solution? In anticipation of implantation, the cells in the lining of the uterus start to undergo specialized changes, (decidualization). Decidualization allows the fertilized egg to implant, and at the same time, limits the egg's invasive ability.
As an aside, occasionally this process breaks down, there's no limiting influence on the fertilized egg, and the results can be [WARNING graphic picture/pathological specimen] disastrous; the woman can die (the tissue keeps growing and growing, it invades through the uterus, into the lungs, the brain).
Returning to decidualization, this process solves one set of problems: it allows the uterine tissue to be ready to accommodate the unique needs of the fertilized egg. At the same time, it creates a new problem for the body--it starts an irreversible clock.
Decidualization happens independent of a fertilized egg. In other words, each month the body jumps the gun if you will. It doesn't actually wait to see if there's a fertilized egg or not. [It doesn't even care if there's any sperm around.] The body gets ready for a pregnancy, period [no pun intended]. However, once decidualization happens, if a fertilized egg isn't there to implant within a certain window of time, the opportunity for pregnancy is lost. Any new fertilized eggs, formed at a later date (e.g., during the next monthly cycle), won't be able to implant. Fortunately, during the menstrual period, the decidualized cells are shed, and brand new cells take their place. These replacements are then able to undergo their own changes, and allow a new fertilized egg to implant.
Returning to the macro level and the uterine cycle, two very important concepts:
a) Fluctuations in hormone levels cause the changes in the uterine lining.
If your hormone levels don't fluctuate, the uterine lining will not thicken, and it will not shed (there's no need to shed it since it's not thick). No shedding means no menstrual period.
b) The only biological reason for these changes in the lining is to prepare the uterus for a possible pregnancy.
Unless you're planning a pregnancy, there's no reason to have any cyclical changes in your uterine lining. Of course, you may still wish to undergo these monthly changes, but you don't have to.
Withdrawal bleeding (Fake period)
When you use a hormonal method of birth control, like the Pill, you no longer have an uterine cycle/a menstrual period. This is normal; it's the way the Pill works and it lasts the entire time you use the Pill. If you use the Pill for 7 years, you don't have uterine cycles/menstrual periods for 7 years. How is that possible?
Briefly, while you take the Pill, your body hormone levels stay low and, most importantly, they don't fluctuate. The levels of Pill hormones are also pretty steady. So, since there are no longer any hormone fluctuations, the lining of the uterus stays thin.
This is very important: the uterine lining stays thin ALL THE TIME, for the entire time you use the Pill (not only throughout the month, but throughout the 7 years in our example above).
No build-up of the lining means no periodic shedding. No shedding means no menstrual period. This is how the Pill suppresses the menstrual period (menstrual suppression). [Keep this term, menstrual suppression, in mind; it's an essential term and we'll come back to it in a moment.]
What you do have when you use the Pill is a monthly withdrawal bleeding episode, or a fake period. This withdrawal bleeding and the menstrual period are not one and the same thing. Briefly, by manipulating the dose of hormones in the Pill, you can destabilize the thin uterine lining enough to cause some bleeding.
But, if the fake and the real period are not one and the same, then why do we have a fake period on the same schedule as the real period, namely, monthly? Again, briefly, because of a Puritanical politician, a Catholic Pope, doctors who didn't wash their hands, and many dead rabbits. In other words, the reason for the monthly schedule of the fake period is a "designer" one, not a biological or medical one. There's no biological or medical reason to destabilize the thin uterine lining monthly.
When the Pill first came out, the concept that any woman can control her fertility was revolutionary enough. Mind you, what was revolutionary was not the desire to control fertility. Throughout history women had been using various methods of birth control (gold shields, plants, potions). With the advent of vulcanized rubber (diaphragms, cervical caps) and the Pill, the groundbreaking event was that safe and effective birth control was finally widely available. Heaping the concept that women could also control their menstrual period on top of their fertility was considered just too much for the political, religious, and societal sensibilities of the 1950s. Enter the fake period. By building-in this monthly bleeding episode into Pill use, the scientists hoped to ease the "shock". [Remember, what we're talking about here is a female health issue, something that, apparently by definition and divine law, requires final approval from politicians, religious leaders, and as many self-appointed "protectors of women" as we can find. In the 1950s, unfortunately just like today, giving women all this control over their bodies and their health was inconceivable; decisions about female health issues couldn't possibly be left to the women and their health care professionals.]
Returning to the fake period, what happens when you use a regular Pill brand and you want to skip "your period", or when you use Seasonale (continuous or extended use)? Let's first see what doesn't happen. The frequency of your menstrual period is not affected. Why? Because when you're using any Pill brand, you no longer have a menstrual period; the menstrual period is suppressed. What does happen is that you're shifting the frequency of your fake period. For example, if you use Seasonale, you're shifting from a monthly fake period, to a trimonthly one. Of course, if you want, you could shift to a bimonthly fake period, or a biannual one. Or you could shift the fake period only once every three years, when you attend a wedding (yours, and your best friend's, of course).
1. The real and the fake period are not one and the same
2. Suppressing your menstrual period by using the Pill on a regular schedule (menstrual suppression) and shifting the frequency of your fake period by using the Pill on an extended schedule (continuous use) are not one and the same, either.
The difference between menstrual suppression (real period) and continuous use (fake period) is important. For example, if you're already using the Pill and you're considering the safety of shifting your fake period, your focus should be on the benefits/drawbacks of continuous use, not menstrual suppression. Unfortunately, almost every single lay article on Seasonale and/or continuous use I read misinforms you about this crucial topic. So, in future posts, we'll go over this in more detail.