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How Effective is the Pill?

One of the most well-known contraceptive options out there, the birth control pill revolutionized the contraceptive landscape when it became available back in the 1960s. As it remains a popular option today,  we’re going to take a look at the birth control pill’s effectiveness, as well as the different varieties available and how they work. We’ll also touch on some other contraceptive options on offer for those who can’t or don’t want to take the pill.

The birth control pill's effectiveness

Before we get started, we want to highlight that no birth control method is 100% effective and no matter what options you go for, there will always be a risk of pregnancy. On top of this, research into birth control methods is carried out on different groups of individuals, this can make it tricky to compare methods side-by-side, but it’s still a useful factor to consider.

When we talk about birth control effectiveness, we talk about both perfect and typical use. Perfect use reflects how a method is intended to be used in an ideal world, whereas typical use reflects how the method is more commonly used. (For example, the occasionally missed pill.)

With perfect use, the birth control pill is more than 99% effective at preventing pregnancy. However, with typical use, the pill it’s 93% effective (meaning 7 out of 100 women in a year taking the birth control pill will get pregnant on average). 

Types of birth control pill

There are a couple of different types of birth control pill available. As well as these two variations containing different hormones, there are different brands of pill containing different doses of hormones too. So depending on your wants and needs, your doctor may recommend a certain type or brand of birth control pill. It’s worth noting that all types and brands of birth control pill are equally effective, they just work in slightly different ways.

Combined pill

The most common birth control pill out there is the combined hormonal birth control pill. It contains both doses of synthetic estrogen and synthetic progesterone. Depending on your prescription, you will either take three weeks of birth control pills and one week of placebo pills or three weeks of birth control pills and then a one-week break. It’s common to experience a withdrawal bleed during the placebo pill period or in the break before you start over with a new pill packet.

Mini pill (progestin-only pill)

Unlike combination pills, the progestin-only or mini pill doesn’t contain any estrogen, only synthetic progesterone. The mini pill usually comes in 28-day packs and all the pills contain hormones. It’s usually recommended as a birth control option for women who are over 35 and smoke cigarettes or who can’t take estrogen for other medical reasons such as a history of blood clots or being prone to migraine headaches with aura (visual symptoms).

How does the pill work?

Both types of birth control pill work in a similar way. The hormones in the pill stop ovulation (the release of an egg cell) from happening. At the same time, it also thickens cervical mucus. This makes it harder for sperm cells to travel through the female reproductive system.

When do birth control pills start working?

This depends on timing. If you start taking them within five days of your last period, you can start having unprotected sex immediately as you’re highly unlikely to get pregnant during this window. If you start taking birth control pills at any other point in your menstrual cycle, then you must wait seven days before having penis-in-vagina sex, or use another form of protection, such as condoms to prevent pregnancy before the pill becomes effective. 

What if I forget to take the pill?

It’s only human to forget to take the pill from time to time. You might find it easier to remember if you take it at the same time each day and build it into your daily routine such as taking it at breakfast or when you brush your teeth at night. Depending on the type or brand of pill, the advice when it comes to missing pills (and how to take pills correctly) is slightly different so check your pill packs for further info or contact your healthcare provider. Keep in mind that there are also certain medications that can also affect the pill's effectiveness. 

Will I have a period when I’m on the pill?

While you might experience a bleed between pill packs, this isn’t technically a period since your menstrual cycle is suspended when you’re taking hormonal birth control. Instead, this light bleeding is a form of spotting called a withdrawal bleed, this is caused by the change in hormone levels. 

The morning-after pill (Plan B)

Emergency birth control comes in a couple of forms and is designed to prevent pregnancy when taken after unprotected sex. The emergency birth control pill (also known as the morning-after pill or Plan B), like all birth control, isn’t 100% effective. However, it can be a helpful option to consider if you’ve had unprotected sex or your contraceptive method has failed and you want to avoid unintended pregnancy. 

The morning-after pill works by delaying ovulation. It’s most effective when taken as soon as possible after unprotected sex, but depending on the brand, emergency birth control pills can work for up to three to five days after unprotected sex.

Some alternatives to the pill

While the birth control pill might be a great choice for some of us, it’s not the best method for everyone. Understanding your birth control options and having a selection of methods to choose from is an important part of making the right decision for your body. Let’s take a look at some alternatives to the pill:


A highly effective form of birth control, intrauterine devices or IUDs are long-acting birth control options that are inserted into the uterus by a healthcare provider. There are two types, the hormonal IUD, and the copper IUD (or copper coil) which is hormone-free. Both methods are more than 99% effective with typical and perfect use as they require no work after they are inserted. Depending on the type of device, they can be used for up to ten years before they need to be removed or replaced.

The birth control shot

Another hormonal contraceptive option that is more temporary than the IUD, but doesn’t require daily work is the birth control injection or shot. This is given around every three months by a healthcare provider. The shot is more than 99% effective when used perfectly and 96% effective with typical use. 

The NuvaRing/vaginal ring

The ring is inserted into the vagina where it gradually releases hormones into your system. The ring stays inside the vagina for several weeks before it is swapped out for a replacement. Rotation can depend on the type of ring you’re using and what your doctor recommends. Just like the pill, it’s more than 99% effective when used perfectly, but 93% effective with typical use. 

The birth control patch

The patch is similar to the vaginal ring in that slowly releases hormones into your system. The patch is typically worn for a week and then swapped out for a new one, after three weeks you take a week off without wearing a patch. The patch is more than 99% effective with perfect use and 93% effective with typical use.

Natural Cycles

If you’re looking for a non-hormonal, non-invasive way to prevent pregnancy, then you might want to consider switching to Natural Cycles. The first FDA cleared birth control app, NC° Birth Control uses temperature data to learn the pattern of your unique cycle to find your fertile window so you can abstain or use protection when there is a risk of pregnancy. Natural Cycles is 98% effective with perfect use and 93% effective with typical use.


As well as protecting against pregnancy, condoms are also useful for protecting us against sexually transmitted infections. Condoms can be used as contraception in their own right, or they can be used as a backup birth control method, adding protection when used alongside another method. With perfect use, the male condom is 98% effective and it’s 87% effective with typical use. 

Our mission and birth control choice

Thanks for taking the time to check out this article! Our mission at Natural Cycles is to pioneer women’s health with research and passion – by empowering every woman with the knowledge that she needs to take charge of her health. Part of that process is promoting contraceptive choice. 

We understand that for many women hormonal birth control is a good solution, but we’re also here to offer a hormone-free alternative for those preventing pregnancy. If you’re thinking about switching contraceptive method, why not find out if Natural Cycles could work for you? 

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Written By

Jennifer Gray

Jennifer Gray is an award-winning writer with more than five years’ experience covering reproductive topics ranging from birth control to planning pregnancy. She is passionate about providing women with accurate information grounded in science they can use to take charge of their own health - while also dispelling myths that exist within the field of women’s health. She holds a Master of Science from the University of Edinburgh and currently lives in Ireland.

Jack in a suit and tie holding a microphone and giving a presentation.

Scientifically Reviewed

Jack Pearson

Dr. Jack Pearson is a previously HCPC registered Embryologist with a PhD in reproductive medicine. Prior to joining Natural Cycles leading Medical Affairs, he worked for more than 10 years in a clinical setting working at some of the busiest fertility clinics in the UK. Today he spends most of his time working with experts at the world’s leading institutions to carry out important research with the vision to further the field of female health. He earned his PhD from the University of Sheffield specializing in Sperm Metabolism and currently lives in London.

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