Natural Family Planning (NFP) is a type of birth control without using any form of contraception. Women who use NFP should not have sexual intercourse when the ovary produces an egg (ovulation) during the menstrual cycle. The NFP method is safe and can prevent pregnancy. It is 75% effective when practiced right. The man needs to also understand this method of birth control and the woman needs to be aware of how her body functions during her menstrual cycle. NFP can also be used as a method of getting pregnant.
A woman's menstrual period usually happens every 28–30 days (it can vary from 23–35 days).
Ovulation happens 12–14 days before the start of the next menstrual period (the fertile period). The egg is fertile for 24 hours and the sperm can live for 3 days or more. If there is sexual intercourse at this time, pregnancy can occur.
The basal body temperature method—Often times, there is a slight increase of body temperature when a woman ovulates. Take your temperature every morning before getting out of bed. Write the temperature on a chart. An increase in the temperature shows ovulation has happened. Do not have sexual intercourse from the menstrual period up to three days after the increase in the temperature. Note that the body temperature may increase as a result of fever, restless sleep, and working schedules.
The ovulation cervical mucus method—During the menstrual cycle, the cervical mucus changes from dry and sticky to wet and slippery. Check the mucus of the vagina every day to look for these changes. Just before ovulation, the mucus becomes wet and slippery. On the last day of wetness, ovulation happens. To avoid getting pregnant, sexual intercourse is safe for about 10 days after the menstrual period and on the dry mucus days. Do not have sexual intercourse when the mucus starts to show up and not until 4 days after the wet and slippery mucus goes away. Sexual intercourse after the 4 days have passed until the menstrual period starts is a safe time. Note that the mucus from the vagina can increase because of a vaginal or cervical infection, lubricants, some medicines, and sexual excitement.
The symptothermal method—This method uses both the temperature and the ovulation methods. Combine the two methods above to prevent pregnancy.
The calendar method—Record your menstrual periods and length of the cycles for 6 months. This is helpful when the menstrual cycle varies in the length of the cycle. The length of a menstrual cycle is from day 1 of the present menstrual period to day 1 of the next menstrual period. Then, find your fertile days of the month and do not have sexual intercourse during that time. You may need help from your health care provider to find out your fertile days.
There are some signs of ovulation that may be helpful when trying to find the time of ovulation. This includes vaginal spotting or abdominal cramps during the middle of your menstrual cycle. Not all women have these symptoms.
You have very irregular menstrual periods and may skip months.
You have abnormal bleeding.
You have a vaginal or cervical infection.
You are on medicines that can affect the vaginal mucus or body temperature. These medicines include antibiotics, thyroid medicines, and antihistamines (cold and allergy medicine).