Medically reviewed by Kristin Hall, FNP
Written by Our Editorial Team
Last updated 10/04/2020
Thinking of starting birth control, or switching from your existing form of birth control to another option? The pill and the IUD are both highly effective ways of stopping yourself from becoming pregnant, each with their own unique advantages and disadvantages.
The birth control pill uses either a combination of hormones or a single hormone to prevent you from becoming pregnant. The IUD, on the other hand, uses either hormones or copper to block sperm from entering into your uterus and causing pregnancy.
We’ve explained how each form of birth control works in more detail below, as well as the major advantages and disadvantages of each form of birth control. We’ve also listed the common side effects you might experience from using the pill or the IUD.
The pill is a form of hormonal contraception, meaning it uses specific hormones to prevent you from becoming pregnant.
There are two different types of birth control pills available. One is the combination pill, which uses a combination of ethinyl estradiol (a synthetic form of estrogen) and a progestin hormone to stop you from becoming pregnant.
The combination pill prevents you from becoming pregnant by stopping you from ovulating, as well as by thickening the cervical mucus inside your cervix. This makes it harder for sperm to physically travel into your uterus, reducing the risk of sperm fertilizing an egg.
The other, the progestin-only pill, doesn’t always cause you to stop ovulating. Instead, it works by thickening your cervical mucus and blocking your partner’s sperm from making their way into your uterus.
Although the combined and progestin-only pill have similar benefits, they also have several key differences. We’ve covered these differences in our guide to combined and progestin-only birth control.
There’s no “best” type of birth control pill for everyone. You and your healthcare provider will choose the most suitable pill for you based on factors like your medical history, age, use of other medications and risk of experiencing side effects.
Whichever type of pill you choose, you’ll be very well protected from the risk of pregnancy if you use the pill correctly. Used perfectly, both the combined and the progestin-only birth control pill are 99 percent effective at stopping you from becoming pregnant.
In “real life” circumstances, with the occasional late or forgotten pill, both types of birth control pill are 91 percent effective at preventing pregnancy. This makes it important to take your pill exactly as instructed to make sure you’re as protected as possible.
The pill is a common and convenient form of birth control. If you take it daily at the same time every day, you may be up to 99 percent protected against the risk of becoming pregnant from sex, all without having to worry about using other forms of contraception.
Not all birth control pills use the same cycle length. Certain pills have a cycle that lasts for 28 days, whereas other birth control pills use an extended cycle that can last for as long as three months at a time.
This means that you’ll be able to skip two out of every three periods if you choose an extended cycle birth control pill.
Since the pill comes with a cycle calendar, keeping track of your cycle is simple. If you make a point of taking your pill every day, it’s usually easy to comply with the instructions provided with your birth control pills and keep yourself fully protected.
As well as keeping you protected from pregnancy and allowing you to skip your period, the pill has a variety of additional benefits.
If you get period pain, cramps or discomfort, you might notice your period becoming lighter and easier to tolerate after you start using the pill. Your period might also become shorter, letting you get back to your normal life in less time every month.
Our guide to how birth control affects your period covers this topic in more detail, with real data on how the pill can make your period easier to deal with.
If you take a combined birth control pill such as Yaz, Estrostep or Ortho Tri-Cyclen, you might also notice your acne disappearing. These three pills can suppress the hormones that are linked to acne and are approved by the FDA as hormonal acne treatments.
Our guide to birth control pills and acne covers this topic in more detail, with links to studies on how combined birth control pills can be used for treating and preventing acne.
The pill can also reduce your risk of developing ovarian cysts, endometrial and ovarian cancers and some vaginal infections. If you use the birth control pill during your 20s, 30s and 40s, it also might reduce your risk of developing osteoporosis when you’re older.
Like all forms of hormonal birth control, the pill has several disadvantages, from side effects to the possibility of becoming less effective if you don’t use it correctly.
First, the birth control pill does have side effects. Most of these side effects are relatively minor, ranging from fluid retention to breast tenderness, nausea and spotting. It’s common for the side effects of birth control to occur during the first few months of use before gradually stopping.
You can learn more about the side effects of the birth control pill, as well as how likely they are to affect you, in our guide to birth control side effects.
The pill also has several less common, more serious potential side effects. The biggest of these is a slight increase in your risk of blood clots. If you’re older than 35 and smoke, taking the birth control pill could significantly increase your risk of experiencing these side effects.
You can learn more about these side effects, as well as the most significant risk factors, in our guide to smoking and birth control.
Second, the pill has the potential to affect your sex drive. Although rare, it’s possible for you to experience a decrease or an increase in your level of interest in sex after you start to take the birth control pill.
There are also practical disadvantages to the pill. In order for it to be as effective as possible at preventing pregnancy, you’ll need to take it at roughly the same time daily. This can be difficult or impractical for many women, for instance, if your job requires you to work on a shift-based schedule or, if like most of us, you’re just plain busy.
While the pill will help prevent you from pregnancy if you use it properly, it won’t protect you from the risk of catching an STI. This means you’ll need to use condoms (or just abstain altogether) if you’re not sure about your partner’s STI status.
The IUD is a small device that’s fitted inside your uterus. It prevents pregnancy by stopping your partner’s sperm from coming into contact with an egg. IUDs can be copper or hormonal, both of which work effectively to prevent pregnancy.
Copper IUDs work by repelling sperm using copper. Copper is a highly toxic element for sperm, meaning the copper IUD can repel sperm and stop them from entering your uterus and coming into contact with an egg.
Hormonal IUDs work by releasing a small dose of progestin hormones into your uterus. These hormones thicken your cervical mucus, physically blocking sperm from coming into contact with an egg.
Like the progestin-only birth control pill, the hormonal IUD can also prevent you from ovulating, although this isn’t a consistent effect.
The IUD is fitted inside your uterus by a healthcare provider or nurse in a process that usually takes less than five minutes. Normally, they will offer you medication before they insert the IUD to make sure you’re comfortable.
Depending on the type of IUD you have fitted, you’ll normally be protected from pregnancy for three to seven years. Some IUDs, such as the ParaGard® IUD, can protect you from becoming pregnant for up to 10 years at a time before they need to be replaced.
Like the pill, the IUD is very effective at preventing pregnancy. On average, both the copper and hormonal IUDs are 99 percent effective at preventing you from becoming pregnant. Because you don’t need to take a pill every day, there isn’t a lower “real life” effectiveness rate with the IUD.
The biggest advantage of the IUD is its convenience. Once it’s fitted, the IUD will last for three to 10 years as a form of birth control. During this time, there’s no need for you to worry about daily pills, weekly patches or other forms of contraception.
Because the IUD works continuously after it’s fitted inside your uterus, there’s no risk of missing a dose or other common issues that can make the pill less effective. It’s also impossible to use the IUD incorrectly, which is a common problem with barrier methods such as condoms.
Because the IUD is available with either copper or hormones, it offers a few unique advantages over other forms of birth control.
If you’re sensitive to estrogen and/or progestin hormones, the copper IUD allows you to protect yourself from pregnancy without any exposure to exogenous hormones. This makes it a possible form of birth control if you experience side effects from the pill, the patch or the ring.
If you experience pain and discomfort before and during your period, the hormonal IUD can help to make your period lighter and easier to tolerate. Many women experience fewer cramps and a lighter, shorter period after they start using the hormonal IUD.
Like the pill, the IUD doesn’t stop you from becoming pregnant in the future. If you decide that you’d like to become pregnant, you can contact your healthcare provider and schedule an appointment for your IUD to be removed.
The IUD stops working as soon as it’s removed, meaning you’ll usually be able to become pregnant as soon as it’s taken out of your uterus.
Finally, some IUDs can be used as a form of emergency contraception. When you have some types of the copper IUD installed, you’ll be 99 percent protected against pregnancy from sex you’ve had in the previous five days.
Like other forms of birth control, with the IUD birth control, there is a risk of side effects. In the first few months after the IUD is fitted, you might experience heavier periods, spotting (bleeding that occurs between your periods) and more severe cramping during your period.
It’s also quite common to experience some discomfort, cramps and back pain in the week after the IUD is fitted.
There are also a few more serious IUD birth control side effects. After it’s fitted, the IUD can slip out of place, increasing your risk of becoming pregnant. It’s also possible to develop an infection if bacteria enter your uterus while the healthcare professional is fitting the IUD.
Most seriously, the IUD could increase your risk of ectopic pregnancy if you become pregnant while it’s installed.
These side effects are rare. However, if you can feel your IUD coming out from your cervix or have painful side effects from the IUD, it’s best to contact your healthcare provider for assistance as soon as possible.
Finally, since the IUD doesn’t create any physical barrier between you and your partner, it won’t protect you from STIs. Just like with the birth control pill, you’ll need to use condoms to help protect against STIs.
Used perfectly, the birth control pill and the IUD are both 99 percent effective at preventing you from becoming pregnant.
There’s no “best” form of birth control for everyone. If you don’t like the idea of having an IUD fitted, have concerns about the side effects or simply prefer taking a pill to using the IUD, you might prefer using the pill.
On the other hand, if you don’t like the idea of taking the pill every day or have concerns about the possibility of missing a dose, you might prefer using the IUD.
It’s up to you and your healthcare provider to decide what’s the best option for you.