Fertility awareness — natural birth control methods

Originally Published: December 11, 1995 - Last Updated / Reviewed On: May 14, 2010
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Dear Alice,

In one of your replies, you said "There is a method of natural birth control that combines basal temperature, with observation of cervical mucus, and continuity of an individual woman's patterns" in the context of how a woman can find out about her fertile and infertile periods throughout her cycle. Could you please elaborate on that method?

—Going natural

Dear Going natural,

Fertility awareness or natural family planning is actually a group of birth control methods, all of which help women to identify fertile times in the menstrual cycle when pregnancy is most likely. Used correctly, fertility awareness can be an extremely effective method of birth control, or on the other hand, a useful tool for women hoping to get pregnant.

Like any birth control method, natural family planning is more effective when used properly. Successful pregnancy prevention with these methods depends on familiarity with your body, accurate record keeping, and willingness to abstain from intercourse or use another method of contraception (like condoms or a diaphragm and spermicide) on "fertile days" when pregnancy is most likely. Fertility awareness works best, either to prevent or promote a pregnancy, when a woman uses several of the following practices in combination:

Rhythm or Calendar method
The rhythm or calendar method estimates fertility based on your menstrual history. Before relying on the calendar method, keep track of your menstrual cycle for at least six months (more is better) while you are not using any hormonal contraception. Websites like My Monthly Cycles can help you log your period. From your records, find your shortest cycle and subtract 18. For example, if your shortest cycle is 28 days, subtracting 18 leaves 10. Counting from the first day of your period, say January 1, the tenth day of your cycle (January 10) is the first day you're likely to be fertile. To find your last fertile day, look in your records for your longest cycle and subtract 11. So, if you longest cycle is 31 days, subtracting 11 equals 21. That means the 21st day of your current cycle (January 21) is the last day you're likely to be fertile. In this example, January 10 to January 21 are fertile or "unsafe" days. The calendar method is not reliable if your cycle is shorter than 27 days or if your cycles are irregular.

Standard days method
The standard days method is a variation of the rhythm method. To use this method, you should have regular cycles lasting 26 to 32 days. Days eight through 19 of each cycle are considered fertile days when you are more likely to become pregnant. Instead of a calendar, some women use a product called CycleBeads with this method to keep track of fertile days.

Temperature method
Most women have a spike in body temperature right after ovulating so it's possible to pinpoint egg release by tracking your basal body temperature. To use this method, take your temperature each morning before getting out of bed and record the measurement to the tenth of a degree (e.g. 98.6 degrees) on a graph. Most women will see a dip in temperature at the beginning of the menstrual cycle, followed by a spike that lasts several days after ovulation. Day one of your cycle through the third day of higher temperature are considered fertile days when you should be abstinent or use another birth control method. The temperature method may not be reliable if you have a fever, restless sleep, or a schedule that requires you to wake up at very different times each day.

Cervical mucus method
Changes in vaginal fluid can also signal ovulation. In general, "wet" days when mucus is available to take care of sperm are considered fertile days, and "dry" days with no discharge are non-fertile days. Mucus usually appears a few days before ovulation. Sticky at first, the mucus becomes increasingly creamy, wet, and slippery, similar to egg white. To test the consistency, you can take a sample and stretch it between two fingers. To prevent pregnancy, you must abstain from intercourse or use another form of birth control from the time mucus appears until the evening of the fourth day after it disappears. (Combining observations of body temp and cervical mucus to detect ovulation is sometimes called the symptothermal method.)

Lactational amenorrhea
Breastfeeding causes hormonal changes in a woman's body that prevent ovulation and menstruation, working as a natural contraceptive. To prevent pregnancy, breastfeeding is most effective in the first six months after giving birth and before a woman's period has returned. To prevent ovulation, women should nurse frequently and avoid formula or other supplements. With exclusive breastfeeding, only two percent of women will get pregnant in the first six months after birth.

To discuss birth control options including fertility awareness, students at Columbia can meet with a clinician at Primary Care Medical Services (PCMS). Visit Open Communicator or call x4-2284 to make an appointment. Online, check out Planned Parenthood for more information about fertility awareness.

Used correctly, natural family planning is a good birth control option for women who steer clear of other contraceptives, for personal or health reasons. Just keep in mind that if you "go natural," fertility awareness methods don't protect against sexually transmitted infections or HIV.

Alice