If you’re sexually active and don’t want to become pregnant, using a safe and reliable form of birth control is your best option for avoiding pregnancy.
There are numerous different forms of birth control available, from over-the-counter products such as condoms to prescription medications and devices such as the birth control pill, patch, ring, implant, IUD and more.
The different forms of birth control that are available vary hugely in effectiveness, with some almost perfect at preventing pregnancy and others significantly less effective.
Below, we’ve explained how birth control effectiveness works. We’ve also listed the most and least effective forms of birth control to help you make informed, effective decisions about your reproductive health and wellbeing.
Before we get into which form of birth control is most effective, it’s important to explain how the effectiveness rate of different forms of birth control is calculated.
If you’ve searched online for information about birth control effectiveness before, you may have seen different forms of birth control mentioned as being “99 percent” or “91 percent” effective at preventing pregnancy.
You may have also seen different percentages used to refer to a contraceptive’s effectiveness in “perfect” and “real life” scenarios.
In order to put these numbers into context, it’s important to understand how they work and what they mean.
The effectiveness of different forms of contraception is usually calculated using a system called the Pearl Index. The Pearl Index measures the number of contraceptive failures (pregnancies) that occur per 100 woman-years of contraceptive use.
In other words, a contraceptive’s Pearl Index measures how many women will become pregnant each year per 100 women using that type of contraceptive. The lower any form of birth control’s Pearl Index is, the more reliable and effective it is at preventing pregnancy.
For example, the hormonal intrauterine device (IUD) has a Pearl Index of 0.16. This means that fewer than one out of every 100 women who use the hormonal IUD will become pregnant during each year of use.
Expressed differently, 99.84 percent of sexually active women who use the hormonal IUD won’t become pregnant each year.
Using no contraception at all, on the other hand, has a much higher Pearl Index of eighty-five. In other words, only 15 percent of sexually active women of reproductive age who don’t use any form of contraception won’t become pregnant each year.
Most forms of contraception have two different Pearl Indexes. The first is the Pearl Index for the contraceptive when it’s used perfectly, while the second takes into account common errors that occur when contraceptives are used in a real-life, non-clinical environment.
These two Pearl Indexes can vary by quite a large amount, especially for forms of birth control that are easy to forget about or use improperly during sex.
For example, condoms have a very low Pearl Index of two when used perfectly, meaning that 98 percent of women won’t become pregnant for each year of perfect use.
However, because it’s relatively common to make mistakes when using a condom, the real life Pearl Index for condoms is 12 to fifteen. This means that only 85 percent to 88 percent of women who use condoms exclusively won’t become pregnant each year.
Depending on the specific resource you use to check birth control effectiveness, you might see the Pearl Index expressed in one of several different ways:
To keep everything simple and consistent, we’ve used the third method for all of the birth control effectiveness rates listed below.
The Pearl Index isn’t perfect — over the years, researchers have highlighted several issues with the way it collects and uses data. It’s also an average based on study findings, meaning it may not translate directly into your exact real-world experience.
However, because of the Pearl Index’s age, simple calculation method and widespread use in studies of different forms of birth control, it’s become the most common method for calculating birth control effectiveness.
Other than abstaining from sex completely, the most effective forms of birth control are those that are good at preventing pregnancy, convenient and difficult to forget about or accidentally use improperly:
Other forms of birth control may not be as effective as the options listed above, either due to a low overall effectiveness rate or a higher risk of making mistakes. Less effective forms of birth control include:
Many types of birth control can vary in effectiveness based on how you use them. For example, condoms are highly effective when used perfectly but become much less effective if you or your partner make a mistake while using them.
To make your birth control as effective as possible and reduce your risk of becoming pregnant, try using the following tips:
Most forms of birth control are relatively easy to use. However, it’s still important that you read the label that comes with your pills, patches or other contraceptives to check that you’re using them properly.
Seemingly small things such as the time of day you take your birth control pill or the exact day you change your patch can have a big impact on the effectiveness of your birth control.
The birth control pill quickly becomes less effective if you forget to take one or several doses in a row. If you often find yourself forgetting to take your pill, try setting a reminder on your phone or keeping your pill pack in a visible, obvious location that you won’t miss.
Condoms are very effective at preventing pregnancy, provided you and your partner have one on hand when the moment strikes. To avoid having to rely on your partner, it’s best to keep at least one condom in your bag so that you’re prepared in any situation.
Keeping a condom or two on hand not only reduces your risk of becoming pregnant — it’s also important for protecting yourself from sexually transmitted diseases (STDs).
Condoms work well when they’re put on your partner’s penis properly, but small mistakes can increase their risk of failure. For example, small things like allowing air to become trapped in a condom can increase its risk of breaking and exposing you to your partner’s semen.
To avoid making mistakes, it’s important to learn how to put on a condom properly. This guide from the CDC covers the right way to use a male condom and points out a few dos and don’ts that you’ll want to be aware of if condoms are your preferred form of birth control.
If you use a hormonal form of birth control such as the birth control pill, patch or ring, using a condom when you have sex will further reduce your risk of becoming pregnant and offer extra protection from STDs.
Population estimates suggest that using condoms with hormonal birth control may lower your risk of unplanned pregnancy by as much as 80 percent. It’s also okay to use condoms with non-hormonal forms of contraception, such as the sponge, diaphragm or copper IUD.
If your form of birth control fails, it’s important that you can access emergency contraception to reduce your risk of becoming pregnant.
Medications such as ulipristal acetate and the levonorgestrel morning-after pill, as well as options such as the copper IUD, can help you significantly lower your risk of pregnancy if used shortly after sex.
To avoid misunderstandings, it’s best to talk to your partner about birth control. Let them know what form of birth control you currently use and talk about how you’d like to make sure both of you stay safe from STDs or an unplanned pregnancy.
If you and your partner aren’t looking to have children, you may also want to talk about a permanent method of birth control such as tubal ligation or vasectomy.
Whatever you ultimately decide on, communicating openly with your partner about birth control can help you avoid misunderstandings and enjoy safer sex.
From condoms to the pill, the IUD and more, there are numerous different options available to reduce your risk of becoming pregnant if you’re sexually active.
Research shows that options such as the intrauterine device (IUD) and hormonal contraceptives such as the birth control implant, shot, pill, patch and ring tend to be most effective at preventing pregnancy when they’re used correctly.
On the other hand, barrier-based forms of birth control, such as condoms, offer protection from some STDs, meaning they may be worth considering. For optimal protection, you may choose to use both hormonal and barrier-based contraception.
There’s no ideal form of birth control for everyone. Choose a form of birth control that’s a good match for your needs, health and lifestyle to keep yourself and your partner protected from an unplanned pregnancy.
Working out which form of birth control to use can often be a confusing process. View our range of generic birth control pills online or read our complete guide to your birth control options to find out more about what’s available and which form of birth control is right for you.