What Is Fertility Awareness? Fertility awareness is a way to try to prevent pregnancy by not having sex around the time of ovulation (the release of an egg during a woman's monthly cycle). Couples who want to have a baby can also use this method to plan sex during the time the woman is most likely to conceive. Fertility awareness is sometimes called natural family planning, periodic abstinence, or the rhythm method. How Does Fertility Awareness Work? If a couple doesn't have sex around the time of ovulation, the girl is less likely to get pregnant. The trick is knowing when ovulation happens. Couples use a calendar, a thermometer to measure body temperature, the thickness of cervical mucus, or a kit that tests for ovulation. The ovulation kits are more useful for couples who are trying to get pregnant. The fertile period around ovulation lasts 6 to 8 days. During this time, a couple using only fertility awareness for birth control should not have sex. How Well Does Fertility Awareness Work? Fertility awareness is not a reliable way to prevent pregnancy for most people. Over the course of a year, as many as 24 out of 100 typical couples who use fertility awareness alone will have an accidental pregnancy. It is often very hard to tell when a girl is ovulating. She can conceive for up to 5 or 6 days before she ovulates and 1 or 2 days after. Because teens often have irregular periods, it makes predicting ovulation much harder. Even girls who usually have regular cycles can have irregular timing of ovulation from things like stress or illness. Fertility awareness requires a commitment to monitoring body changes, keeping daily records, and not having sex during the fertile period. Does Fertility Awareness Help Prevent STDs? No. Fertility awareness does not protect against STDs. Couples having sex must always use condoms to protect against STDs, even when using another birth control method. When Should I Call the Doctor? A girl who uses fertility awareness should call the doctor if she: might be pregnant has a change in the smell or color of vaginal discharge has unexplained fever or chills has belly or pelvic pain has pain during sex Back to Articles Related Articles Birth Control Methods: How Well Do They Work? Some birth control methods work better than others. This chart compares how well different birth control methods work. Read More Emergency Contraception Emergency contraception is a way to prevent pregnancy after unprotected sex; for example, if a condom breaks or slips off during sex. It is also available to teens who are forced to have unprotected sex. Read More About Birth Control Before you consider having sex, you need to know how to protect yourself. Read this article to get the basics on birth control. Read More STDs (Sexually Transmitted Diseases) You've probably heard lots of discouraging news about sexually transmitted diseases. The good news is that STDs can be prevented. Find out how to protect yourself. Read More Abstinence Abstinence is the only form of birth control that is 100% effective in preventing pregnancy. Abstinence also protects people against STDs. Read More Gyn Checkups Girls should get their first gynecological checkup between ages 13 and 15. Find out what happens during a yearly gyn visit -- and why most girls don't get internal exams. Read More Female Reproductive System Why do girls get periods? What goes on when a woman gets pregnant? What can go wrong with the female reproductive system? Find the answers to these questions and more in this article for teens. Read More Condoms Condoms may be a good birth control option for couples who are responsible enough to use one each time and people who want protection against STDs. Read More Talking to Your Partner About Condoms Some people - even those who are having sex - are embarrassed by the topic of condoms. Here are some tips for talking about condoms with your partner. Read More Note: All information is for educational purposes only. For specific medical advice, diagnoses, and treatment, consult your doctor. © 1995-2021 KidsHealth®. All rights reserved. Images provided by The Nemours Foundation, iStock, Getty Images, Veer, Shutterstock, and Clipart.com.