How effective is birth control?

Different methods have different levels of effectiveness. Some methods, like the condom or pill, depend on how well you use them, while others, like the IUD or implant, don't require the user to do anything special to make them effective. Effectiveness of birth control is reported as the number of pregnancies in 100 couples using the method for a year. Each method has two numbers reported -- one that reflects perfect use, and the other that reflects real-life use (because nobody's perfect.)

The top-tier reliable and reversible methods are the IUD and the contraceptive implant. There is nothing you have to do to make these methods effective, so the perfect use and real-life use numbers are the same. Fewer than one in a hundred couples using this method get pregnant each year. The next tier are the hormonal methods that depend on the couple to do something daily, weekly, or monthly to make them work. Used perfectly, the methods result in fewer than one in one hundred patients getting pregnant over the course of the year. However, many couples find it difficult to use these methods consistently and correctly.

With the birth control shot, Depo Provera, many couples miss the appointment for reinjection. For that reason, the real-life effectiveness is much lower, and about six in one hundred couples get pregnant every year while using the injection.

The birth control ring, NuvaRing, has to be changed out once a month. The patch has to be changed weekly. The pill must be taken daily. These have an error rate high enough that nine in one hundred couples using it get pregnant every year.

Condoms are easy to use in conjunction with another method, like the pill or the ring. One of their advantages is that the male partner can ensure that he is protected against fatherhood by using them correctly and consistently. If 100 couples use condoms perfectly over the course of the year, two couples may have a pregnancy. Since so many couples using condoms don't use them every time they have sex, 18 in 100 couples using condoms for birth control get pregnant over the course of the year. That's almost one in five! Withdrawal or pulling out is another method that men can control. Of 100 couples using withdrawal over the course of the year, 27 will have a pregnancy. It's better than doing nothing at all, but the chances of it failing are high.

Because effectiveness rates vary so much, and depend on how committed and able the partners are to using the methods, it's important that you talk with your partner about how important it is to you to avoid pregnancy right now. What would it be like if you got pregnant this year? What kind of assurance do you need that a pregnancy won't happen? Considering those questions, and your ability to use each method correctly, can help you determine what level of protection you need.