How Effective is FAM for Contraception?
How Effective is FAM for Contraception
When you search 'fertility awareness method effectiveness' this is the first link, from Planned Parenthood.
76%-88% doesn't sound like a reliable method, and many people will see this and dismiss this as a reliable contraceptive. People simply use the '1/4 of couples will get pregnant in their first year using this' and that, reasonably, makes people skeptical.
So where did this statistic come from and why have I, a practicing user, been able to avoid pregnancy for the past 4 years?
The 24% failure number comes from this CDC table. FAM based methods, when used typically are listed with a 24% failure rate. Notice that there is complete data for all method types with the exception of the FAM section, in a few key areas.
First off - defining typical vs perfect use is important here.
Typical use: how well it works when real people in real life use it.
Perfect use: how well the method works when it’s used in a clinical trial. A properly informed user can greatly improve their rate of effectiveness in this method.
The typical use rates for individual FAMs are missing from this table. One reason for this could be because it is hard to measure typical use of these various methods which have a low # of users & are dependent on informed users.
However, a combined # of 24% is provided.
Also note that the CDC does provide a further breakdown of FAM methods, but only lists the perfect use rate of effectiveness. These statistics are provided from much smaller and less diverse population sizes.
I use the symptothermal method which is listed as having a perfect use rate of 99.6% in the table above.
All of the other contraceptive data in this table is provided from the National Survey of Family Growth. It is a larger analysis of population data across a wide spectrum of demographics. Clinical trials which are far smaller sized studies, give us different numbers, but this is intended to reflect self reported users.
Yet 86% of those who reported using 'fertility awareness based methods' in this typical use data actually report using the rhythm/calendar method specifically. [1]
As an informed user myself, it is obvious to me that this makes the 24% typical failure rate highly skewed.
The 24% number provided is more representative of people using the rhythm method than of users practicing reliable fertility awareness based methods. Unfortunately predictive methods, like the rhythm method, are calculated alongside the symptothermal method, which relies on diagnostic & retroactive fertility signs. It also admits that there has been serious lack of research in fertility awareness based methods.
Calendar & rhythm methods, in my opinion, should not be combined with fertility awareness based methods because these methods have clear dissimilarities which should be distinguished from one another. The former is not a reliable or accurate method. It's a system of prediction & counting. It is unreliable because it doesn't acknowledge the changes in an individual user & that ovulation can be delayed due to various circumstances & hormonal shifts. These variables are accounted for in fertility awareness based methods.
Another reason for the lumping of these methods is the low rate of FAM use (2-3% of contraceptive users) compared to the rest of the contraceptive options. This makes the data more unstable & so instead of eliminate it from the table, the CDC chose to combine to produce a typical use %. This choice has resulted in many people wrongly assuming that 1 in 4 couples will have an unintended pregnancy using fertility awareness without learning what the method is or how it works.
Although comprised of a smaller population, this is a peer reviewed journal from 2013 which does list typical use rates for a few different kinds of fertility awareness based methods. As you can see the symptothermal method (STM) ranked extremely well (0.4 - 0.6 perfect use failure) (1.6-2.2 typical use failure).
Although the CDC is presenting a broad range of data here meant to reflect scientific rigor, ultimately more education around FAM & more studies must be conducted as more users begin to learn about and utilize fertility charting.
Fertility Awareness Study Effectiveness Quality Review
In 2018 the first quality review was conducted on studies on fertility awareness based methods. [2]
"Our comprehensive systematic review of the effectiveness of fertility awareness–based methods for avoiding pregnancy reveals that the current evidence base for each method is small and of low to moderate quality."
"We identified several important limitations of the existing literature. No study achieved a high-quality rating across all 13 criteria (Table 2)."
"Many people believe they are using a fertility awareness–based method to avoid pregnancy when in fact the method they are using has not undergone a standard prospective effectiveness assessment. Several methods shown in italics in Table 1 (including many increasingly popular internet applications) have no prospective trial data available to support their effectiveness yet are nonetheless being marketed as effective ways to avoid pregnancy. We strongly encourage investigation of the effectiveness of any new adaptation of existing fertility awareness–based methods, including internet-based versions. Likewise, users who make their own modifications should be counseled that effectiveness estimates from a specific fertility awareness–based method may not apply to their use of the method."
This review should be considered when choosing which fertility awareness method works for you. The review concludes that we need much more study into fertility awareness based methods, and that none of the studies performed thus far are of high quality.
So we have very different statistics here. What does it all mean?
The above review ranked the symptothermal method study [Frank-Herrmann] of moderate quality. This is the study where we derive the 99.6% perfect use rate number from, and you may hear people refer to this effectiveness rate when talking about fertility awareness.
This 24% failure number is inaccurate to describe fertility awareness methods which rely on daily biomarkers such as the symptothermal method. It is just a part of the information we have to counteract to teach this method as a viable option for people to use effectively. The effectiveness of fertility awareness is a lot more complicated than it's presented to be.
The CDC has finally, in 2019, changed the range of typical use failure rates on their website. It is now listed as 2-23%, varying between methods, instead of the 24% statistic.
Still, this doesn't teach people about body literacy nor does it make any distinction between the vast differences between, say, the rhythm method & the symptothermal method. But it is an improvement to acknowledging that this method is a viable option for menstruating people.
Ultimately, what all of this tells us is that fertility awareness has been understudied & disregarded by the medical community. They have been resistant to learning about how charting can benefit them or their patients, and they have refused to present proper studies all the while disregarding it as unreliable. To date, there has never been a high quality fertility awareness method study globally, and the best information we have is from outside the USA. This method is relatively autonomous & does not make pharmaceutical companies a lot of money, so we can surmise this may have something to do with why there has been such resistance to getting accurate data surrounding FAM.
Every contraceptive method has a risk of failure. As a practicing user, I've learned that the risk of failure with the symptothermal fertility awareness method is extremely low when practiced correctly and in solidarity with your sexual partner[s].
In 47 cycles, I have had zero unintended pregnancies with 47 ovulations. This was not by accident but because I followed the rules strictly and completely for the past 4 years. I hope to be a part of the gathering of data and to eventually contribute the statistics that can prove fertility awareness is a viable, reliable method for menstruating people.
Citations
[1] Duane Marguerite, R. Motley and M. Manhart. “Letters to the Editor: Physicians Need More Education About Natural Family Planning.” American Family Physician 88, no. 3 (August 2013): 158-159. https://www.aafp.org/afp/2013/0801/p158.html.
[2] Rachel Peragallo Urrutia, MD, MS, Chelsea B. Polis, PhD, Elizabeth T. Jensen, PhD, Margaret E. Greene, PhD, Emily Kennedy, MA, and Joseph B. Stanford, MD, MSPH. "Contraception: Review Effectiveness of Fertility Awareness–Based Methods for Pregnancy Prevention A Systematic Review." 2018 by the American College of Obstetricians and Gynecologists. Published by Wolters Kluwer Health, Inc. https://www.replyobgyn.com/wp-content/uploads/2019/01/ACOG_Urrutia-Systematic-Review.pdf