Family planning without contraception? The stats on NFP


Is natural family planning reliable?

Is it safe?

The short answer to both questions is “Yes!”

But you don’t have to take our word for it. There are plenty of data to back up that claim.

Natural Family Planning, or NFP, has been thoroughly studied by researchers around the world, both in medical settings and in real life application.

There is overwhelming evidence that:

  • If a couple’s goal is to avoid pregnancy, NFP is as effective as any contraception in “typical use” scenarios
  • NFP can be used to help achieve pregnancy, even for many couples diagnosed as clinically subfertile
  • NFP has no “side effects” since it is not a medical treatment

We’ll review some of that evidence in a moment.

But, before we begin, here’s a very brief summary for those who may not be familiar with NFP.

What is Natural Family Planning?

Natural Family Planning isn’t complicated.

NFP makes use of the fact that conception is only possible during a specific portion of a woman’s monthly cycle, often referred to as her “fertile days.”

During a woman’s “fertile days,” there is some likelihood that intercourse will lead to conception and pregnancy. During a woman’s “infertile days,” there is essentially no chance of conception.

The key to Natural Family Planning is this: using simple, home based techniques, a woman can learn to tell the difference.

Most methods of Natural Family Planning depend on a woman’s observation her cervical fluid and basal body temperature over the course of her cycle; Ovulation is indicated by the blue line

With a few hours of training, and some simple, inexpensive tools, a woman can discern with great precision whether she may become pregnant as a result of intercourse on any given day.

How effective is natural family planning for avoiding pregnancy?

The largest peer-reviewed study of natural family planning was published by researchers at the University of Heidelberg, Germany, in 2007. This study looked at data from the German Natural Family Planning Study Centre from 1985-2005.

The researchers came to the following conclusions:

  • Overall, NFP was 98.2% effective at preventing pregnancy
  • In cases of “perfect use,” among couples who abstained from intercourse during the woman’s fertile phase, NFP was 99.6% effective at preventing pregnancy
  • In cases of “perfect use” in which the couple chose to use a barrier method of contraception during the woman’s fertile phase, NFP was 99.4% effective

The researchers found that even among couples who showed “imperfect use” of NFP methods, NFP was 92.5% effective at preventing pregnancy. They suggest that the majority of the “imperfect use” cases were actually instances where the couple chose to have intercourse when the woman was fertile, but not highly likely to become pregnant.

In other words, even couples who practiced NFP “imperfectly” were still keenly aware of their fertility potential each day.

Dr. Petra Frank-Hermann, the lead author of the study, asserts:

Therefore, we maintain that the effectiveness of [NFP] is comparable to the effectiveness of modern contraceptive methods such as oral contraceptives, and is an effective and acceptable method of family planning.

What if the couple is trying to conceive?

Often, discussions of family planning center around prevention of pregnancy.

In reality, that’s only part of the story.

And – when you get down to it – it’s probably the less important part!

Conception isn’t something that simply happens. It’s a product of active choices, an expression of a couple’s love for each other, and their desire to create new life together.

NFP is unique among family planning methods, in that the principles of Natural Family Planing can be used to actively increase the chances of conception, not simply to avoid it.

study of 346 German couples, published in Human Reproduction in September 2003, found that 81% of participating couples – all of whom who were trying to conceive using Natural Family Planning methods – became pregnant within 6 months, and 92% in 12 months.

Among “truly fertile” couples the overall rates of conception were even higher: 88% at 6 months, and 98% at 12 months.

The study results are summarized below:

Table I. - Time to pregnancy study
Percent of participating couples who achieved pregnancy in 1, 3, 6, and 12 months respectively; from C. Gnoth, D. Godehardt, E. Godehardt, P. Frank‐Herrmann, G. Freundl, Time to pregnancy: results of the German prospective study and impact on the management of infertility, Human Reproduction, Volume 18, Issue 9, September 2003, Pages 1959–1966,

Noting that approximately 40% of participants achieved pregnancy within 1 month, and 70% within 3 months, the authors write:

These findings highlight the existence of a huge group of highly fertile couples who conceive quite early within six cycles with timed intercourse.

These rates of conception are significantly higher than ordinary: current clinical opinion expects 60% of TTC couples will become pregnant within 6 months and 80% within 12 months.

Another study, published in Gynecologic Endocrinology and Reproductive Medicine in February 2017, indicates that the use of NFP methods can double the chances of conception in couples who are having difficulty conceiving.

This study followed a group of 187 women, aged 21-47, and diagnosed as clinically “subfertile,” for 8 months. All of the couples were actively trying to conceive, and had thus far been unsuccessful for 42 months on average.

At the beginning of the study, participating couples were given basic instruction in Natural Family Planning methods.

Here’s what happened:

  • After 8 months, 38.1% of these couples had conceived.
  • Among couples under 35 years old, who had been attempting to conceive for less than 2 years, 56% had conceived before the conclusion of the study.
  • Among women over 35 years of age, and couples who had been attempting to conceive for over 2 years, the rates of conception were 25% and 17% respectively (significantly higher than baseline expectations for each subgroup)

The baseline expectation overall – i.e. if these couples were not using NFP techniques – was that about 21.6% percent would conceive.

The researchers conclude:

Training women to identify their fertile window in the menstrual cycle seems to be a reasonable first-line therapy in the management of subfertility.

In other words, NFP can often help couples who are diagnosed as subfertile to conceive, without the use of clinical fertility treatments.

Is NFP difficult to practice?

NFP is often criticized as being too hard for most couples.

However, this is not always the case.

The University of Heidelberg study cited above showed an “attrition rate” of about 9.2 percent – that is, 9.2 percent of participating couples chose to cease using NFP methods before the conclusion of the study. The researchers state that, while direct comparisons are difficult to make, this 9.2% attrition compares favorably with the various methods of contraception, some of which have attrition rates as high 30 percent.

In our opinion, practicing NFP is about as easy as brushing your teeth regularly.

Of course, everyone’s experience is different.

For some, NFP might feel like a chore.

For some, it might be a breeze.

Why is NFP so little-known?

We remember when we first studied NFP, during our last year of college together.

We were shocked.

It was such basic knowledge.

How had we never learned it before?

Most of our friends, our family, and our students have had a similar experience.


Well, for one thing, most doctors are not trained in NFP.

A 2017 study titled “Medical Students’ Knowledge of Fertility Awareness-Based Methods of Family Planning” explored this issue. The authors begin by noting:

Traditional medical school curricula have not addressed fertility awareness-based methods (FABMs) of family planning.

Their research showed that doctors who don’t understand Natural Family Planning methods are unwilling to discuss these methods with patients. However, after receiving basic instruction and information about NFP/FABMs, the doctors who participated were much more willing to discuss these methods with their patients.

We have heard similar stories anecdotally.

A friend told us of his experience in medical school:

I don’t hear anyone speaking out against the method. It’s simply not mentioned.

Another friend (who is also ones of our students) told us:

In my training as a nurse, the ‘reproductive segment’ merely consisted of methods of chemical contraceptives and a vague reference to the ‘rhythm method.’ As a medical student, my husband had a similar experience.

At present, NFP is not part of the standard medical curriculum.


We don’t know.

Certainly not because it doesn’t work.

What does this mean for you?

We can’t answer that.

Family planning is a deeply personal process. We’re definitely not here to tell anyone what to do. If we were, we expect you would probably stop reading right about now! ????

Our goal is simply to convey knowledge – to make NFP available to you.

We believe that you, and every person of childbearing age, deserve the following:

  • To be aware of the scientific research which demonstrates that NFP is a reliable option for family planning
  • To have access to basic NFP instruction, so that you may understand what is required to apply NFP in a relationship

We know that NFP is not for everyone.

However, we do believe that everyone deserves to understand NFP.

NFP must be included in family planning education, as a valid, trustworthy, medically sound option.

Certainly, for some people, in some relationships, NFP will be difficult to practice, but in many relationships, NFP may be the best choice.

We have heard from our students, time and time again, that NFP has opened the door to profound benefits and growth for them as couple.

It certainly has done so for us.

Perhaps it will do the same for you.

We invite you to check out the first few lessons of our NFP course for free.

Click below to get started:


Free NFP Lessons

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