How natural family planning works

Natural family planning is a form of birth control that is based on the avoidance of sex during a woman’s fertile days. It is based on a good understanding of the menstrual cycle. You need to realise from the outset that natural family planning is not as effective as most other methods of contraception. About one in every four women who use natural contraception may end up with unwanted pregnancies.

There are a variety of methods for natural contraception. The success or failure of these methods will depend on your ability to recognise the signs that ovulation is about to occur, and avoid having sex during this fertile period. And if sex is unavoidable, you may choose to transiently use another method such as condoms. For most women, ovulation occurs about two weeks before the start of the next expected menstrual period. The egg is able to be fertilised for about 24 hours after it’s been released. Sperms, on the other hand, can live in a woman’s body for three days or more, retaining the potential to fertilise an egg all this time.

The calendar or rhythm method is among the most popular. It requires keeping a record of the length of your menstrual cycles for at least six months. You can then work out your fertile days backwards by subtracting 18 days from the shortest cycle, and 11 days from the longest cycle. The days in between are the fertile days when sex must be avoided. If your periods are irregular, the calendar method becomes unreliable. Ovulation involves changes in the mucus produced by the cervix. Sticky mucus occurs after menstruation, and then just before ovulation, the mucus becomes wet and slippery. Thereafter, the mucus becomes thick again, or disappears. You can choose to regularly check for mucus changes at the opening of the vagina. The fertile period, when sex must be avoided, occurs with the start of the mucus and continues for four days after the last day of the wetness.

Other natural choices include the temperature method. The body temperature increases slightly just after ovulation. Sex must be avoided after the menstrual period till three days after the rise in temperature. Body temperature can be affected by a multitude of events, making this method somewhat unreliable. You could always choose to combine body temperature with other signs of ovulation to increase reliability. Exclusive breastfeeding also provides a contraceptive effect, most reliably in the first six month.

You may opt for natural family planning for various reasons, but be sure to discuss this with your family planning provider first. Some women will have conditions that make natural family planning unsuitable for them. A degree of stringency is required; otherwise you’ll end up with an unwanted pregnancy.