I should assume that the logic is that the women can control when the are going to have their menstrual cycle, and they also wont have to be on it the all the time, like remembering to take the pill at the same time every day.
The birth control patch prevents pregnancy by stopping sperm from meeting an egg (which is called fertilization). Like most birth control pills, the patch contains the hormones estrogen and progestin, which are similar to hormones our bodies make naturally. You wear the patch on certain parts of your body, and the hormones are absorbed through your skin.
The patch stops your ovaries from releasing eggs (called ovulation). No ovulation means there’s no egg hanging around for sperm to fertilize, so pregnancy can’t happen.
The patch’s hormones also thicken the mucus on your cervix. Thicker cervical mucus makes it hard for sperm to swim to an egg — kind of like a sticky security guard.
