I’ve been doing the 21/7 method for 10 years now, and recently I was thinking about how they drill into us that we need to take it exactly the same time every day, or it’ll be less effective. Or when we miss it, it’ll be less effective. Make sure to use condoms for a week if we miss it more than twice. All that jazz. Women are told to opt for different methods of contraception if they aren’t able to commit to taking it 100% regularly.
From what I know, the pill works by keeping the hormone cycle steady, to prevent an egg from maturing. After 24h, there is a spike in some hormone which the pill normally keeps steady (I think it’s progesterone but not 100% sure), so we take the pill, and the hormones remain in tact.
Surely then by not taking it for 7 whole days would mess the entire thing up. How come the risk of pregnancy stays low after 7 days, if missing it for 1 day can increase it?
In: 3
So for all normal healthy women, there’s a 7-day period of the monthly cycle where you’re *naturally* infertile, because of a certain hormone. The way the pill works is basically by tricking your body into thinking you’re *always* on that portion of the cycle, so you’ll be infertile all month, instead of just during a fraction of it.
But when that 7 day period comes, you don’t want to be taking the pill because that would give you an *excess* of the hormone, and that would make you sick. If you took the pill during that 7 day period you’d be getting like a *double-dose* of the hormone, you’d be getting both your natural body’s production of the hormone *and* the artificial version that you take as a pill. So for that 7-day period (and *only* on that seven day period), you don’t take the pill as normal.
So it’s not that you can miss the pill for 7 days and still be fine. It’s that during those 7 days your body is already *naturally* “on the pill”, and you’d be taking too much if you were to also take the actual pill during those days.
The menstrual cycle is a complex interaction of hormones between the body and the egg. The contraceptive pill is only replacing half of that interaction, the egg. The body will produce all the normal hormones it does. And in a regular menstrual cycle there is a period where no eggs are producing any hormones while the body still produces hormones as usual. A lot of contraceptive pill prescriptions actually comes with placebo pills for this period to make the instructions simpler.
I’m not a doctor, but this is how I understand it-
The reproductive female hormone is very complicated, and involves multiple different hormones waxing and waning in amounts throughout the body. There are 4 phases throughout a ~28 day cycle: menstrual, follicular, ovulation, and luteal. Your estrogen levels vary a lot during the cycle, but they drop after the luteal phase heading into the menstrual phase (your period) if no egg is fertilized.
The idea of estrogen based BC pills is it keeps the estrogen high so that the body never enters the ovulation phase.
The default estradiol-progesterone birth control pill sometimes has a 7 day break period to allow the body to have a period. The menstrual cycle is part of the cycle and estrogen is naturally low during this time, so your body is still following a semi normal cycle. It is used to not having as much estrogen. Your body is just doing its thing.
However missing an unplanned day or taking it at the wrong time interrupts the cycle completely, which can cause weird hormone levels and ovulation.
There are different types of BC though and they all work a little differently. That’s the idea of the classic “pill” though, IIRC. Recent studies have shown that the week off isn’t really all that necessary anyway. Some people just choose to keep taking the normal pills all 4 weeks instead of taking placebos, and that’s okay too.
The active pills keep you at a hormone level where you don’t ovulate. Its not exactly mimicking any given part of the cycle, more kind of negating it mostly, just using hormones that are (fairly close to) those your body uses to regulate it naturally.
The time off the pills is to allow a period, which in this case is a withdrawal bleed from the estrogen – this is kinda like a normal period, but actually closer to the mini period baby girls sometimes get after birth when they lose exposure to their mum’s estrogen.
The timing is just marketing and comfort really – there’s no reason the 21/7 is better, its just fairly average cycle length so that’s what the makers settled on. It used to be thought to be important for health reasons to have the bleed, turns out that doesn’t seem to be the case. Only downside of skipping the break seems to be breakthrough bleeding, so often people just find the timing of breaks that works for them and go with that – someone might need one 2 monthly to avoid spotting, someone else could go 6 months without issues.
Latest Answers