Welcome to the latest installment of “Over 90 Percent of What Planned Parenthood Does,” a series on Planned Parenthood Advocates of Arizona’s blog that highlights Planned Parenthood’s diverse array of services — the ones Jon Kyl never knew about.

Fertility awareness is not the same as the rhythm method.

Let’s start there.

It’s a common misconception that is, at best, a massive oversimplification that misconstrues the concept and may lead people to dismiss or deride fertility awareness out of hand. In reality, a lot of people could benefit from a more thorough understanding of fertility, as many sexually active couples spend a lot of their lives trying to control it — whether to avoid or achieve pregnancy. Planned Parenthood health centers provide education in fertility awareness-based methods (FAMs) for a variety of purposes.

If fertility awareness is not just the rhythm method, what is fertility awareness?

For someone having menstrual cycles, fertility awareness involves monitoring cycle signs and symptoms — predominantly cervical fluid and basal body temperature, though these are often supported or “cross referenced” by tracking other signs as well — in order to determine when a person is approaching ovulation and/or to confirm when ovulation has already taken place.

How does that even work?

Fertility awareness-based methods rely on a few underlying assumptions about fertility and the likelihood of conception:

For pregnancy to happen, there must be both sperm and an ovum (egg) present. Ovulation — the release of an egg from the ovary into the fallopian tube — occurs once per menstrual cycle. Sperm can survive inside someone with a uterus for approximately five to six days. (Note: The actual number a given person or couple will want to use for this assumption can vary a bit depending on whether their main goal is to achieve or avoid pregnancy.) The ovum itself is viable in the fallopian tube for approximately one to two days. After that, it begins to disintegrate, and fertilization is not possible during that cycle. (Again, different couples may use different assumptions depending on their goals.)

FAM uses different signs and signals from the body to determine what is called the “fertile window” — the five or so days before ovulation, the day of ovulation, and the one to two days after ovulation. Generally, FAM users track cervical fluid changes to determine when the fertile window begins and monitor waking temperature (basal body temperature) to confirm when the fertile window has passed. The “fertile window” is the time period during which having otherwise unprotected intercourse would be the most likely to result in pregnancy. Penis-in-vagina intercourse outside the fertile window is unlikely to lead to pregnancy, and intercourse on days quite far from the fertile window are very unlikely to end in fertilization.

Of course, what any given person or couple chooses to do with this information once they’ve identified their fertile window is fairly individual. For example, couples trying to avoid pregnancy may choose to abstain from intercourse or use a barrier method, such as condoms, during their fertile window, while couples trying to conceive will likely try to have intercourse during this time.

What are some reasons people might use fertility awareness education?

This list isn’t exhaustive, but people may choose to use fertility awareness as:

general cycle monitoring in order to predict their periods. (Because FAM includes using signs from the current cycle, it is often more accurate than simply estimating based on the length of past cycles.)

background information to understand the mechanism of action of another form of contraception. (For example, because contraceptives that contain both estrogen and progestin generally work by suppressing ovulation, they eliminate the ovum from the sperm-plus-ovum equation. Thus, taken correctly, there is no “fertile window” while taking a combined hormonal contraceptive.)**

a secondary form of contraception to back up a compatible method (for example, condoms).

a primary form of contraception, generally accompanied by a secondary method (barrier or behavioral).

a tool to aid in conception.

a tool for someone experiencing cycle-related concerns — for example, irregular menstrual cycles or difficulty conceiving — to bring more specific, detailed information to health care providers.

And, of course, it’s also possible for folks to have multiple reasons for learning fertility awareness, whether they’re concurrent or applicable at different points in their lives.

As a method of contraception, just how effective is fertility awareness?

Because it requires a lot of participation from the people using the method, there’s a substantial difference between FAM’s effectiveness for perfect versus typical use. According to Contraceptive Technology, perfect use of fertility awareness is from 95 to 99.6 percent effective, depending on the specific method used. Typical use, however, is only about 76 percent effective.

If fertility awareness has such a low typical use rate, why would people choose it as a method of contraception? Does it have any advantages?

As a matter of fact, it does. Some of those advantages include:

There are no medication side effects or adverse reactions to materials (such as latex or spermicide) to worry about.

It’s relatively inexpensive — an initial investment for learning the method, a one-time cost for a basal thermometer, and the cost of record-keeping materials (online or with pencil and paper).

It is compatible with religious beliefs that may not permit other forms of contraception.

It is also compatible with many other behavioral and barrier methods of contraception. Combining methods can help reduce overall risk of pregnancy.

It can be easily and immediately discontinued — or continued with a change in focus — for couples who would like to become pregnant.

And disadvantages, right? Every method has disadvantages.

Yes, every method has disadvantages, and fertility awareness is no exception. In addition to the lower typical use effectiveness rate, some disadvantages of fertility awareness as contraception include:

It does not protect against sexually transmitted infections.

It requires specific and somewhat detailed education before use. Additionally, some “trial cycles” — monitoring fertility signs while consistently and correctly using a secondary, compatible method of contraception — are ideally recommended before relying on FAM as a primary means of contraception. Depending on location and other resources, this education may be difficult to obtain — though you can inquire at your local Planned Parenthood health center.

It requires more or less daily intervention on the part of users, regardless of how often the couple has sex. Moreover, it requires a certain amount of record keeping in order to observe changes over the course of multiple cycles. This may make consistent and correct use of the method more involved or difficult.

It requires the incorporation of an additional compatible behavioral or barrier method — for example, outercourse or condoms — during the fertile window. If the couple chooses a less effective method to use during this window, it may increase their overall risk of pregnancy.

The method works best when everyone involved is on the same page about the restrictions of the method (i.e., when the chosen secondary method is needed) and the reasoning behind it.

This may well mean that fertility awareness is not the best choice for every sexually active person. However, for many people, fertility awareness is useful knowledge to possess, whether it’s used as part of a contraception plan or not.

You have just written an awful lot about fertility awareness, and I’m not even sure how it all works yet. When are you going to get to that?

It’s true. In upcoming posts, I’ll be detailing different aspects of fertility awareness. These include:

an overview of the menstrual cycle

the role of cervical fluid in fertility awareness

the role of basal body temperature in fertility awareness

the role of cycle charting in fertility awareness

the role of other secondary cycle signs in fertility awareness

If you’re interested in learning more about fertility awareness as soon as possible, contact your local Planned Parenthood health center. If you’re just a body geek like me — because, hey! they are neat! — stay tuned until next time.

**Note: Because most hormonal contraceptives can interfere with the menstrual cycle and alter cervical fluid, it’s not possible to actually monitor cycle signs for FAM while using such a method. However, receiving fertility awareness education in advance can help create a better understanding of how the hormonal method works, which can help increase compliance and/or speed correction (for example, obtaining emergency contraception) in the case of errors.