Scarleteen

Hello

Why, in the combined pill, do we take the placebo phase? I understand (to a point) what it does, and I understand that skipping a placebo phase doesn't alter the effectiveness of the pill at all. So why do pills come with them? I've heard it's to "give your body a break" from the hormones the pill gives, is this true? What happens if our body never gets that break?

When you're taking the combined pill (or using another kind of combined hormonal contraception), you still have a kind of cycle; it's just a bit different to the menstrual cycle that happens without any hormonal contraception. The week without taking hormones is a part of the cycle, and it contributes to keeping the cycle going. In an unchanged menstrual cycle, the four main hormones involved all impact each other, some increasing the production of another, and other ones blocking or reducing another's production.

With the combined pill, the uterine lining typically builds up a lot less than it would in an unchanged cycle. There's still likely to be some lining created, though, and the body will need to shed that at some point. Menstrual flow is triggered when levels of progesterone drop; combined pills contain a progestin (synthetic progesterone), so when you have the placebos, your levels of progestin will drop. So: menstrual flow

These pieces, and some of their links, have more details on what's going on with the hormones in these cycles:
How do birth control pills really work, even during the placebo period?
Three questions about taking the birth control pill (and plenty of answers) (the first section)

Does all that help shed more light on it for you?

it does, thank you! If there's any way this section could be expanded on, I'd be really grateful: "With the combined pill, the uterine lining typically builds up a lot less than it would in an unchanged cycle. There's still likely to be some lining created, though, and the body will need to shed that at some point."

What happens if that lining doesn't shed? And what's the "limit", like I know that if for whatever reason you need to, you can skip a placebo phase and go straight onto the next packet of active pills, but does this skipping become more detrimental to health if you do it more than once? I'm just asking for the sake of knowing, if that's alright

Studies indicate it's perfectly safe for over-18s to skip placebos somewhat regularly, so long as they have 4 periods a year (unless my maths-brain is being wonky, I think that's a period at least once every three months). There's simply a lack of study on under-18s for this. For anyone wanting to do that, though, we would suggest discussing it with a healthcare provider first. Not least because, to my knowledge, there are some formulations which are more likely to be prescribed when that's what someone wants to do.

Bodies will tend to do what they need to do. In practice, that means that some people have a bleed even when they skip the placebos, and that there's a higher chance of getting breakthrough bleeding after skipping placebos than there is with taking them.

Ah, thank you for being so informative!