Eli5 How do birth control pills not cause a build up in uterus lining

Question

In a normal period, the uterus lining is thickened and then shed during the period.

What happens to the lining when using birth control pills? If it’s not shed does it not just keep on getting thicker and thicker?

In: 13

Answer 1

You still get a period on birth control. On the pill though, usually the uterine lining thins. So periods often get lighter. It varies on what pill you are on though. However, there’s no build up…business as usual.