One form of natural family planning is the calendar method (or the fertility awareness method or the rhythm method). This approach is based on the regular patterns of fertility that most women have and avoiding sex during the time of the month when the woman is most likely to become pregnant. In other words, it is timed abstinence.
How the calendar method works
The basic idea of the calendar method is to be abstinent during the time of month when the woman is fertile and can become pregnant. First, you must first try to predict when you will next ovulate. Unless you already know that you’re “regular,” meaning that your period always comes at the same time in your cycle, your first step is to determine what pattern you follow.
Your fertile period is not just the day that you ovulate. The egg lives for one to three days, but sperm can live inside the vagina from two to seven days. This means that, if you have had sexual intercourse before the time that you ovulate, any of those sperm may still be hanging around the fallopian tubes when the egg comes along, ready to ambush the egg and impregnate the woman.
To be safe from pregnancy, you should think of a nine-day period as being risky — five days before you ovulate, the day of ovulation, and three days after that. During that fertile period, you should either abstain from sexual intercourse or use a barrier method.
The other 19 days that comprise the cycle are considered to be “safe,” and — theoretically — you can have sexual intercourse during those days without using any other method of birth control and not become pregnant.
Calendar method: Advantages and disadvantages
The calendar method is risky — both for unintended pregnancy and sexually transmitted disease — but it is an option for birth control without purchased contraceptives.
*Advantages of the calendar method: Obviously, the calendar method does not require any doctor appointments or any purchases and it comes without side effects.
*Disadvantages of the calendar method: The number-one drawback is that many women are not all that regular, and even those who are regular sometimes have irregular months. When that happens, an unintended pregnancy can result. If your pattern tends to be very irregular, natural family planning carries more risk of pregnancy for you.
Also, natural family planning precludes sex more often than approximately 19 days of the menstrual cycle (and keep in mind that many of those theoretically safe days are during menstruation, which some people avoid).
Even if you are presumably safe from becoming pregnant, that doesn’t mean that you are safe from getting a sexually transmitted disease. Unless you are certain that your partner is 100 percent safe, you should make sure that a condom is in place before attempting intercourse.