Rhythm Method

What is the rhythm method?

The rhythm or calendar method is one of the 'biological' forms of birth control. A couple attempts to avoid sexual intercourse just before, during and just after ovulation, a time when an egg is exposed to potential sperm as it travels out of the ovaries and down one of the fallopian tubes.

This method of birth control has come under heavy scrutiny as of late. Research conducted by Dr. Allen J. Wilcox for the National Institute of Environmental Health Sciences suggests that "there is hardly a day in the menstrual cycle during which some women are not potentially fertile" (for the full article click here). In light of this new research, couples serious about birth control (as opposed to family planning) may be advised to select a more reliable method.

How effective is the rhythm method?

The effectiveness of the rhythm method depends on how meticulously you practice it. It also depends on the predictability of your periods and consequently your ovulation period. For typical users the rhythm method is less than 87% effective. Also, the rhythm method is only effective in preventing pregnancy and not STDs.

How does one practice the rhythm method?

The rhythm method requires specific personal instruction and diligent study which are beyond the scope of this guide. Please see your doctor or family planning center if you wish to begin using the rhythm method. What follows is a brief description of how the rhythm method is practiced.

Theoretically, ovulation occurs about 14 days before the start of a woman's period. Since sperm can live inside the vagina for up to 3 days, and an egg can stay fertile in the fallopian tubes and vagina for up to another 3 days, intercourse must be avoided for more than just the day of ovulation. To be safer, a woman should abstain from sex (or use a barrier method) 5 days before ovulation, and 5 days after. Of course, this method has many limitations which are described in the section below.

Practical concerns with the rhythm method.

The rhythm method is by no means a flawless method of birth control. Firstly, the rhythm method requires that a woman have regular periods, and many women do not. This fact limits the number of women who are eligible. The second major limitation is that even if your periods seem regular, a one-time change in the timing of ovulation can alter the expected days of infertility. If that is so, you may be having unprotected sex during a time when you think you can’t become pregnant.