Mis-conceived: Is Fertility Awareness Risky Birth Control?

What FABM user hasn’t heard the “oh, you use Fertility Awareness? Hope you’re ok with getting pregnant!”

Or perhaps you said something like this to a friend, and they sent you to this article.

The discussion of unplanned pregnancies when using Fertility Awareness Based Methods (FABMs) can be filled with myth and misunderstanding. It seems everyone has a friend whose family member used fertility awareness and got pregnant! Let’s take a closer look to remove the mystery of unintended pregnancies and fertility awareness.

Most birth control methods have a mechanism that restricts the ability of the body to conceive when it otherwise might: a condom or diaphragm provides a barrier for the sperm, hormonal birth control pills inhibit ovulation, and the copper IUD prevents the fertilization of an egg. These methods’ efficacy rates reflect the odds of that mechanism having some mechanical failure, which the user may or may not notice in time and which results in an unintended pregnancy.

There is a great misconception believed by many that women are equally fertile every day of their cycle. However, we know that there are actually an average of only 6-10 fertile days in a cycle when we consider the lifespan of sperm and egg combined (check out the 2015 edition of Taking Charge of Your Fertility (Toni Weschler), p.164 for more information on this).

Let's say you're going for a walk in the park. To make sure you never get rained on, you always carry an umbrella. If you know when it's going to rain, you don't need to bring an umbrella everyday. Why carry an umbrella if there’s no chance of getting rained on?

Fertility Awareness works differently from other methods. Fertility Awareness accounts for the fact that women aren’t fertile every day, and educates them on reliable and evidence-based ways to identify those days. FABMs themselves don’t provide any umbrella -- that is, no mechanism to stop conception on fertile days. But Fertility Awareness does do something other birth control doesn’t: it can identify if rain is possible, which informs the user to take appropriate action. By helping a user identify their fertile window, FABMs allow each user to paint an individual picture of when they should or should not have unprotected sex to achieve her fertility goals.And this isn’t some shot-in-the-dark weather channel forecast: FABMs are really, really, good at identifying those risky fertile days - because nobody knows your body, like your body.

FABMs leave it up to the user to decide if they want to go out on their walk in the park during the risk of rain, and if they do, it lets them pick if they want an umbrella... or a raincoat, or rain boots, or whatever meets their needs and preferences.

To summarize:
  • Fertility awareness based methods’ purpose is to enable the user to identify their fertile days and infertile days: the days conception is possible, and the days it’s impossible.
  • Fertility awareness based methods do nothing to prevent pregnancy during the fertile days.

This awareness isn’t automatic. Users can’t just “put it on” like you might put on a rain jacket. Each FABM has different “rules” that the user must follow to identify a day as non-fertile and each has a different efficacy rate, with more effective methods being generally correlated with how detailed their rules are.

Despite the differences, there is one common thread: FABMs require research and commitment, but the payoff in flexible choices, body literacy, and lack of side effects is uncomparable.

With all this in mind, understanding the distinct categories of unintended pregnancies that occur in users of FABMs is important for understanding the reality of the risks involved in using the methods.  

1. User Failure

The biggest mistake someone can make with FABMs is not doing the appropriate research and disregarding the tools and commitment that are required to properly use FABMs. FABMs don’t do the work for you, they simply better help you understand how your body works. It is the user’s job to interpret and record their data correctly from the start, and without proper education and understanding, FABMs can easily be misused.

The Symptothermal Method has 4 rules that must be followed to ensure proper identification of infertile days.

When user failure occurs, a pregnancy happens because the user didn’t follow the rules: something important goes unnoticed or a rule is misunderstood or forgotten, and the user misidentifies the fertile window. For the Symptothermal Method, this might be mis-marking a peak day (rule #3), not taking basal temperatures accurately (rule #4), misidentifying cervical fluid (rule #2-3), or having sex during their period after a cycle where they didn’t confirm ovulation (rule #1)… to name a few.

Sometimes a user knowingly takes a known risk and hopes for the best. This might be a choice, not an accident, but it is still a user failure. The FABM didn’t fail, it wasn’t used correctly.

User failures define the “imperfect use” distinction and are included in typical use rates. These failures are avoidable by having reliable and thorough support from a FABM instructor who can check charts and help a user achieve perfect use of your chosen method.

2. Fertile Window Method-of-Choice Failure

Let’s recall:

  • Fertility awareness based methods’ purpose is to enable the user to identify their fertile days and infertile days: the days conception is possible, and the days it’s impossible.
  • Fertility awareness based methods do nothing to prevent pregnancy during the fertile days.

Sometimes FABM users get pregnant due to the failure of the protection method they used during the fertile window, when their FABM indicated it wasn’t safe to have unprotected sex.

Once the fertile window opens, it’s up to the user to decide what to do instead of having unprotected sex on those days: abstinence, sexual activity other than intercourse, or using withdrawal or a barrier method are popular choices. For many users, FABMs offer an helpful alternative to having to use those methods every time they have sex.

When FABM users select another method during the fertile window, their chances of getting pregnant become based on the efficacy rates of that method, not the FABM. If the condom breaks, or withdrawal doesn’t happen in time, it’s not the “FABM’s fault.”

These failures are often excluded from research on FABMs, because a FABM’s true efficacy rate is based on how effectively the method identifies the fertile days, not how effectively it prevents pregnancy in the fertile window (remember, it doesn’t!). Many studies on FABMs mandate participants observe abstinence in the fertile window in order to ensure the FABM’s true efficacy rate is calculated.

3. Method Failure

This is the type of failure that FABM has in common with every other method of birth control -- the failure where sometimes things just don’t work the way we have designed or understood them to. No birth control method is 100% effective. Method failures are the failures that aren’t necessarily preventable, and the failures included with perfect use rates.

Some FABMs are more prone to method failure than others, as different methods have different “perfect use” efficacy rates.

For the standard days method -- a method whose identification of the fertile window relies on averages and assumes that ovulation will occur in the same average-based window each cycle -- a method failure might be caused by fertile cervical fluid showing up and helping keep sperm alive from before the averages account for, or ovulation that occurs earlier or later than average.

The Symptothermal Method’s perfect use rate is 99.4%. These failures could be attributed to rare circumstances around sperm life and rare ovulation timing. 99.4% means that out of every 200 people using the method perfectly, about one will get pregnant within a year. This number, while unfortunate, is comparable with birth control pills, showing that even our most elaborate contraceptive technologies are still subject to marginal, inevitable failures that we can’t quite prevent.

In the end, it is important for everyone to be able and empowered to choose a method of birth control that works with their lifestyle and that they feel good about. Like any choice about birth control, the decision to use a FABM is a matter of weighing the pros and cons. Whether you choose to use a Fertility Awareness Based Method or not, it is important to understand the true nature and causes of accidental pregnancies that occur while using FABMs in order to discuss the topic accurately.

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