Many people follow their body’s menstrual cycle to know when they have the highest chance for pregnancy. They might do this to avoid pregnancy, or to get pregnant! Following a person’s menstrual cycle is sometimes called the Fertility Awareness Based-Method ( or FAB method). FAB methods are types of family planning or birth control.
What are Fertility Awareness-Based (or FAB) Methods? How do they work?
There are several different types of Fertility Awareness-Based Methods. Some of the most common include:
- The rhythm method, also known as the calendar rhythm method or the calendar method
- The cervical mucous method
- The basal body temperature method
- The symptothermal method
These methods use different signals in different parts of the body to help someone know when they have a higher or lower chance of pregnancy.
A person has the highest chance of becoming pregnant on the days that they ovulate. Ovulation is when the body makes an egg that can be fertilized by sperm when it makes its way to the uterus. On average, a person ovulates between 12-16 days after their period starts. But this can vary a lot, and may change between periods! Everybody is different.
If a person doesn’t want to get pregnant, they can use a Fertility-Awareness Based Method to know when their risk of pregnancy is the highest. That way, they can avoid sex or use condoms or other birth control when they’re ovulating! Or, if they’re trying to get pregnant, they can have sex without birth control when they are ovulating.
FAB, FAM, rhythm method: Are they all the same? What are the differences?
There can be a lot of confusion around the different Fertility Awareness-Based methods. Some people use “Fertility Awareness Methods” (or FAM) as an umbrella term for all FAB methods. That’s because FAB methods have a few important things in common. They’re all based around using signs in the body to try to predict when someone has a higher or lower chance of getting pregnant!
But different Fertility Awareness-based methods also work differently, and can have different rates of effectiveness when it comes to preventing or increasing the chances of pregnancy.
For example, the most basic FAB method is sometimes called the rhythm method. The rhythm method involves using someone’s past menstrual periods to try to predict what their future periods might be like. This method works best if someone has regular periods. But not everyone does!
Other types of Fertility Awareness-Based methods do not rely on past information. These methods include:
- The cervical mucous method, where someone keeps track of the texture, colour, and other qualities of the mucous produced by their cervix. Changes in the cervical mucous can be a sign that someone is ovulating.
- The basal body temperature method, where someone keeps track of their resting body temperature. Ovulation can raise someone’s resting body temperature slightly.
- The symptothermal method, which involves combining the basal body temperature method with other FAB methods, like the cervical mucous method or the rhythm method.
Instead of using past information, these methods rely on tracking signals from the body on an ongoing basis. This means a person would keep track of what’s happening to their body every day, like by taking their temperature or looking at their vaginal discharge.
How effective are Fertility Awareness Methods at preventing pregnancy?
Unfortunately, while there’s a lot of research on Fertility Awareness Methods, the overall effectiveness isn’t super clear. So it can be hard to know for sure the chance of pregnancy for each type of method!
In general, researchers and health professionals acknowledge that each FAB method has a different chance of pregnancy. What we do know is that as many as 24% of people get pregnant using FAB methods with average use. “Average use” accounts for common mistakes that people might make when using birth control, instead of assuming that everyone will always use birth control perfectly. This means that an average of 24 out of 100 people get pregnant if they use FAB methods to prevent pregnancy.
How can I know if an FAB Method is right for me?
Because of these rates, most experts don’t recommend using FAB methods alone to prevent pregnancy. But, combining them with another type of birth control, like condoms, can help make that birth control even more effectively! And FAB methods can be very useful for someone who is trying to get pregnant. How someone uses a FAB method is up to them!
The important thing is finding a method of birth control or family planning that works for you. You can talk to a doctor or your sexual partner(s) about what kinds of birth control you are and aren’t comfortable with! For more on other types of birth control, check out our FAQs on hormonal and non-hormonal birth control methods.