Merck Manual

Please confirm that you are not located inside the Russian Federation

honeypot link

Overview of Contraception

By

Frances E. Casey

, MD, MPH, Virginia Commonwealth University Medical Center

Reviewed/Revised Aug 2023
VIEW PROFESSIONAL VERSION
Topic Resources

Did You Know...

  • The effectiveness of certain contraceptive measures, such as the pill or rhythm methods, depends a great deal on how well instructions are followed.

There are many methods of contraception. None is completely effective, but some methods are far more reliable than others. Effectiveness often depends on which method is used and how closely people follow instructions. Thus, the effectiveness of a birth control method can be described in two ways:

  • How well it prevents pregnancy when used by most people (typical use)

  • How well it prevents pregnancy when instructions for use are followed exactly (perfect use)

For example, oral contraceptives (birth control pills) are very effective if a woman takes them every day (perfect use). However, forgetting to take a few pills (typical use) decreases the effectiveness. In contrast,intrauterine devices (IUDs), once inserted, require nothing more until they need to be replaced. Thus, typical use is usually the same as perfect use. People tend to follow instructions more closely as they get used to a method. As a result, the difference between effectiveness with perfect use and with typical use often decreases as time passes.

Table

Besides its degree of effectiveness, each contraceptive method has other advantages and disadvantages. Choice of method depends on preferences, degree of reliability needed, and medical considerations.

Despite the higher pregnancy rate associated with condom use compared to other methods, condoms (primarily latex and synthetic condoms) provide protection against all common sexually transmitted infections (STIs), including human immunodeficiency virus (HIV) infection. As part of safer sex practices, condoms should be used even when another birth control method is also being used.

Table

More Information

The following English-language resource may be useful. Please note that THE MANUAL is not responsible for the content of this resource.

  • Planned Parenthood: This web site provides information about birth control, abortion, and other subjects related to reproduction.

NOTE: This is the Consumer Version. DOCTORS: VIEW PROFESSIONAL VERSION
VIEW PROFESSIONAL VERSION
quiz link

Test your knowledge

Take a Quiz!
iOS ANDROID
iOS ANDROID
iOS ANDROID
TOP