What is Natural Family Planning (NFP)?

Most women are fertile for about 8 days each cycle, (5 days before ovulation, ovulation and 2-3 days after ovulation). NFP is a combination of several methods used to determine when a woman fertile period. It may be used to help a couple become pregnant, or to avoid pregnancy. When used correctly, it is 80 to 90% effective in preventing pregnancy. It does not provide any protection against Sexually Transmitted Diseases (STDs). It is very inexpensive, but it does require accurate charting of the woman’s menstrual cycle, body temperature and observation of her cervical mucous. It also requires the support of her partner to refrain from intercourse during her fertile time, or use a barrier method of contraception such as a condom and/or diaphragm. It is also more effective if your menstrual cycles are fairly regular (24-35 days from the beginning of one cycle to the beginning of another cycle).

How to Chart Your Cycles to Determine Your Fertile Period

  • You need to record on a calendar, when your period begins and how long it lasts. You need to do this for several months, some experts recommend 8-12 months.
  • Once you’ve charted your cycles for a while, look at the calendar and find out what your shortest cycle is. Subtract 18 from this number (for example if your shortest cycle is 26 days, 26-18 = 8). Starting with your next cycle, mark on the calendar the day it starts and then 8 days from that put an X on the calendar. (For example, if your next period started on the 2nd, put an X on the 10th). This is the first day of your fertile time.
  • Next, subtract 11 days from the total days of your shortest cycle (26-11 = 15). Mark the calendar with an X on the date that is 15 days after the start of your next cycle. (If your cycle starts on the 2nd, put an X on the 17th). This is the last day of your fertile time.

How to Measure Your Basal Body Temperature

  • A woman’s baseline, or basal, temperature is her temperature when she is relaxed and resting. This is usually first thing in the morning when she wakes up.
  • A woman’s basal temperature is usually between 96-98 degrees Fahrenheit before she ovulates. The temperature will increase between 0.4-1.0 degrees Fahrenheit after she ovulates.
  • If you record your basal temperature every day over several months, it will give you a good idea of what day in your cycle you usually ovulate.

Examine Your Cervical Mucus

  • Just after your period, you may not produce much mucus for several days. These are called a ‘dry days’. Just before ovulation, you will notice mucus that is clear, slippery and stretches between your fingers. This is a sign that you are in your fertile time.
  • This is followed by several days when the mucus is cloudy and sticky and is a sign that you are less fertile, and is followed by several more ‘dry’ days before your period starts.
  • It can be helpful to record on the calendar ‘dry’, ‘slippery/clear’, and sticky/cloudy’.

When all three techniques of fertility awareness are used together, it is possible to predict when you are most likely to ovulate, and when you are most fertile. Below is a link to a fertility calendar you can print out to use. In addition, there are NFP support groups, websites and iPhone apps which provide additional free resources.