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How fast do birth control pills work? If you’re new to the pill, it’s an obvious and important question to ask— after all, the whole point is to avoid a pregnancy! The answer to this isn’t completely straight-forward as it can vary depending on a few different factors. So, keep reading below for answers to this question!

Are All Birth Control Pills the Same?

Before we can dive into answering the question at hand, there are some important things to know about the pill—the most important being that there are two types of pills.

There are combination birth control pills and progestin-only birth control pills.

Combination pills, as the name implies, contain a combination of the hormones estrogen and progestin. On the other hand, progestin-only pills (POPs) only contain— you guessed it— progestin! For this reason, POPs are also often called the mini-pill.

Brands such as Alesse, Yaz, Yasmin, Ortho Tri-Cyclen, and Seasonique are all combination pills. Brands such as Errin, Heather, Jolivette, and Ortho Micronor are POPs.

How do Birth Control Pills Work?

Combination birth control pills work mainly by suppressing ovulation. In other words, they prevent the release of an egg. With no egg, fertilization and, subsequently, pregnancy cannot occur.

Combination pills also make your cervical mucus thicker, thereby making it more difficult for sperm to pass through. In addition to this, it also makes the lining of your uterus thinner. A thinner uterine lining makes it more difficult for a fertilized egg (should it happen) to embed and result in a pregnancy.

POPs, on the other hand, only suppress ovulation in about half the users. Its main job is to thicken the cervical mucus to make it harder for sperm to reach the egg. Furthermore, just like the combination pill, it also thins the uterine lining, making it difficult for a fertilized egg to embed.

So, How Fast do Birth Control Pills Work?

Information for how fast do birth control pills work?

For combination pills, it depends on when you begin your first pack.

If you begin the pill on the first day of your period, they’ll work right away to prevent pregnancy. However, if you start it any time after your period, give it 7 days before they start protecting against pregnancy. In that time, be sure to use condoms or a female condom if you have sex.

You can start taking POPs at any time during your menstrual cycle. However, the amount of time for it to take effect isn’t quite the same as the combination pill. According to Planned Parenthood, it takes 48 hours for the mini-pill to take effect when you start it. So, if you have sex any time between then, be sure to use a backup method as well!

It’s important to keep in mind that the mini-pill has a lower dose of hormones than the combination pill. The hormones are effective for only around 24 hours which is why it’s important to take it at the same time every day. So, if you’re late in taking it or miss a pill, be sure to use back up contraception during those 48 hours again.

So, to sum up the answer to “how fast do birth control pills work?”, check out the chart below:

Type Start Time of First Pack Duration to Become Effective
Combination 1st to 5th day of period Protects against pregnancy immediately
Combination Any time after period 7 days to become effective and protect against pregnancy
Progestin-Only Pill Any time during menstrual cycle 48 hours to become effective and protect against pregnancy


Birth Control Pills Effectiveness Rate

Birth control pills effectiveness

When used perfectly, the birth control pill’s effectiveness rate is over 99%. However, with typical use, it has a 9% failure rate, as noted in an article by Healthline. That means 9 out of 100 women will get pregnant in a year.

This is why it’s important to take the pill on time and to maintain a regular schedule. If you have trouble remembering to take it on time, consider apps like Popit.

However, if you still can’t stay on track, don’t fret. Consider long-term, reversible birth control options instead. The IUD and birth control implant are great options as they require zero effort on your part. You simply have them inserted and… that’s it, really!

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