How Effective Is the Birth Control Pill?

Why It's So Popular, and Why It Sometimes Fails

Close up of white pills and one red pill
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Question: How effective is the birth control pill?

Answer: Taken properly, the birth control pill (an oral contraceptive, also referred to as the pill) is one of the most effective methods of preventing unplanned pregnancy, with a 99.7 percent success rate. Of course, exactly how effective the pill is for you depends on whether you take it every day. Missing just one pill significantly raises your chance of getting pregnant, lowering its effectiveness to 92 percent.


And in fact, in the small percentage of cases in which pregnancy does occur for someone on the pill, the cause is typically user error.

In order to remember to take your pill daily, it can help to keep your pill packet in a highly visible area where you are likely to see it. Doctors also recommend taking it at the same time every day, making it an integral part of your regular routine.

On average, about five to eight out of every 100 couples will get pregnant every year while using the pill.

What Does the Pill Do That Makes It Work So Well?

The pill works by preventing a woman's body from ovulating during her monthly menstrual cycle. This means that the ovary will not release an egg while you're on the pill, so that there will be nothing for any sperm to fertilize.  

While on hormonal contraception such as the pill, your cervical mucus (the fluid around the cervix / opening of the uterus) also becomes thicker, and stickier.

As a result, when sperm try to get through the cervix, it's much harder for them to swim through. The lining of the uterus also changes while on hormonal contraceptives. The uterine tissue may thin out or stop growing entirely. This can lower the chances that implantation will take place.

Are There Any Contraceptives That Are 100 Percent Effective?

Abstinence is the only 100 percent effective method to use in order to prevent both pregnancy and the transmission of sexually transmitted infections (STIs).

All other birth control options carry some risk of failure, even if that risk is minuscule.

If abstinence is not an option, however (and it's probably not if you're asking about contraception), there are other methods available that don't carry the risk of user error. One such option is an intrauterine device (IUD), a form a long-acting reversible contraception (LARC). All you have to do is ask your doctor to slide an IUD into your uterus, after which it can remain there for the next five to seven years, working its magic with no activity on your part. Another form of LARC is the hormonal implant, which is placed under the skin in a woman's upper arm, where it works for the next three years.

There are also options for surgical sterilization.

You should talk to your doctor about the pros and cons inherent with all of these options, and use that information to decide which option is best for you.

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