Does NFP work?
Yes, and it’s 99% effective. (That’s better than many other methods of hormonal birth control!)
How do we know?
Studies. With real women. And decades of data. (Four decades, to be exact.)
The science has already been figured out for you. The data has been analyzed, the method has been refined over years of research.
For some readers that is enough on this subject. But if you’re like me and need more info to be convinced or just want to understand how method effectiveness is calculated, read on.
To really answer the question “does NFP work” we first have to get on the same page about a few terms.
When we talk about a method being some percent “effective” what we really mean is how likely are we to become pregnant?
There are two categories to consider when rating a method: perfect use and typical use. The biggest difference between the two ultimately comes down to personal motivation and discipline.
[Note to the reader: For purposes of this website I am discussing data for the sympto-thermal method of NFP because I believe it is the most reliable. The sympto-thermal method is so named because it combines the use of all available signs of fertility rather than relying on one alone. Since it provides a more complete picture of what’s going on with your body I recommend it, and it is the method I practice myself. But just know that there are other methods of NFP that do exist, each with their own associated method effectiveness data.]
With perfect use, NFP is upwards of 99% effective. Perfect use of NFP for avoiding pregnancy requires daily temperature tracking plus abstaining during your fertile time, which typically lasts 8-10 days during the cycle. And for that to work you have to accurately identify the fertile time of your cycle, which in turn requires being properly educated on how to recognize your own individual signs of fertility each cycle.
Typical use effectiveness is more difficult to measure since there are many variables involved. For example, a couple might decide one month that, although they’re not actively trying to conceive, if it did happen a pregnancy would be ok for them and then choose to abstain fewer days than they otherwise would. Studies of couples strictly seeking to avoid pregnancy with typical use of NFP state 1% chance of pregnancy, while couples less concerned with avoiding pregnancy had typical use pregnancy rates of 16%.
The point is, if you really want to avoid getting pregnant, NFP will absolutely work provided you properly educate yourself to practice the method and maintain the necessary discipline. Arguably this aspect of NFP is no different than the same discipline required to take a pill every day. But the result is a LOT different for the overall health of your body!
My husband and I successfully avoided pregnancy for 5 years using NFP. We chose to be conservative and strictly followed the recommended guidelines because we were both highly motivated to postpone pregnancy at that point in our lives. Later, when we were ready for a baby, we used the same fertility awareness we had gained – with the added benefit of years of practice – to conceive (immediately). So yes, I can definitively say NFP works – both for avoiding and achieving pregnancy.
Ready to learn how NFP can work for you?
To learn more, check out the page that matches your current goals: avoiding pregnancy or achieving pregnancy.
To work with me, check out this page.