Why does stopping the contraceptive pill for 7 days not mess with the effectiveness of it?

Question

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

Answer 1

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.