It can also prevent ovulation.
If the first pill is taken within the first 5 days of the start of a woman’s menstrual cycle, in other words, the first day of her period, it works immediately.
Women who have a cycle shorter than 23 days, however, will need to wait 2 full days.13 Nov 2017
How long does it take for the pill to kick in?
But depending on when you start and the kind of pill you’re using, you may need to use a backup birth control method — like condoms — for up to 7 days. If you start combination pills within 5 days after the first day of your period, you’ll be protected from pregnancy right away.
Does the pill work immediately?
When does the pill start working after you take it? The pill doesn’t start working immediately. You need to take it for at least a few days before it becomes effective. That’s why it’s important to use a backup contraceptive, like condoms, when you first start taking it.
How effective is the pill?
Birth control is a way for men and women to prevent pregnancy. There are many different methods of birth control, including hormonal contraception such as “the pill.” Women take the pill by mouth to prevent pregnancy, and, when taken correctly, it is up to 99.9% effective.5 Aug 2018
How does the pill work?
The birth control pill works by stopping sperm from joining with an egg (which is called fertilization). The hormones in the pill stop ovulation. No ovulation means there’s no egg hanging around for sperm to fertilize, so pregnancy can’t happen. The pill’s hormones also thicken the mucus on the cervix.