Many people follow their body’s menstrual cycle to know when they have the most chance for pregnancy. They might do this to avoid pregnancy or get pregnant. This is sometimes called using the rhythm method. You might also hear about the fertility awareness method (FAM), which uses more involved tracking. Both of them can be used as birth control and people also use them to get pregnant.
Both the rhythm method and FAM try to predict when someone will ovulate, or release an egg. When someone knows when they’ll ovulate, they can figure out which days they have the highest chance of pregnancy. Then they can avoid sex or use condoms or other birth control on these days. Or, if they’re trying to get pregnant, they can have sex without birth control on those days.
When is there the highest chance for pregnancy?
Everyone’s different and it takes at least a few months of tracking before someone can know when the chances are highest. On average, people have the most risk for pregnancy if they have sex 7 – 17 days after their period started. This is when sperm might live in someone’s body until they ovulate, or release an egg.
But, that’s just the average. Everyone’s cycle is different, and the days with the highest chance can change a lot. This is especially true the first few years after someone’s first period.
When it’s used for birth control, as many as 24% of people can get pregnant if they just use the rhythm method with common mistakes. This means that an average of 24 of 100 people get pregnant if they just use fertility awareness to prevent pregnancy. If it’s used perfectly by tracking things like vaginal temperature and discharge along with periods, this can go down to 2%.
How does the rhythm method work?
Pregnancy can happen when an egg from an ovary meets a sperm from a penis. Once the two meet, they join together. This is called fertilization. If a fertilized egg joins the wall of the uterus, someone is pregnant.
Someone also needs to ovulate for pregnancy to happen. This is when an egg has moved from an ovary into a Fallopian tube. On average, ovulation happens between 12-16 days after a period starts. But, this can vary a lot, and change between periods. Typically, an egg hangs around for 12-48 hours after ovulation.
For pregnancy to start, sperm needs to be in the Fallopian tubes. This usually happens after a penis has ejaculated semen (cum) inside the vagina. Sperm can live in the body for 3 -5 days. They can fertilize an egg any time in these days.
This means that someone can avoid pregnancy by making sure there is no living sperm in their body when they’re going to ovulate. So, if someone has a cycle that’s exactly the average, they might choose not to have sex for between the 7th and 17th days after their period started. But everyone’s body is different, and many people have cycles that aren’t the average. People’s cycles can also change because of diet, stress, exercise, or common changes during teenagehood.
How do I track my menstrual cycle?
The rhythm method just uses periods to track ovulation, but this isn’t very reliable. This is especially true for people with irregular cycles, like many teenagers.
The Fertility Awareness Method is a more accurate way to track ovulation. It uses a few more signs of ovulation:
- Basal body temperature (someone’s body temperature right after they wake up)
- Changes in the cervix (the opening to the uterus, at the top of the vaginal canal)
- Changes in cervical mucus (the sticky fluids that come out of your vagina)
It’s recommended that people gather as much information as they can for accurate tracking. This means looking at their vaginal fluid 3 times a day before peeing, taking their body temperature as soon as they wake up, and feeling their cervix once a day. By charting these for a few months, they can predict when they might ovulate. They can record these signs in a calendar or an app like Kindara or Eve.
What are the signs that someone is ovulating?
There are a few clear signs that can mean someone’s ovulating:
- Their cervix at the top of their vagina will be softer.
- Their cervical fluid, which comes out through the vagina, will be more stretchy, slippery, and sometimes clear or white. It might look and feel like the whites of a raw egg.
- Some people feel a bit of pain in their lower stomach when they ovulate. This is because the egg is coming out of the ovaries.
- The day after they ovulate, their basal body temperature (their temperature right after waking up) will usually be higher than the days before.
Does the rhythm method work?
Ovulation tracking can be effective birth control if someone does it right. But it’s very easy to make mistakes. Many people have irregular cycles or don’t measure their temperature the right way. Some don’t record their temperature, cervix hardness, or cervical mucous often enough. Some people also don’t track these signs for long enough before they try to predict when they’ll ovulate.
The fertility awareness method or the rhythm method can also not work as well for teens and younger adults. This is because their menstrual cycles can be unpredictable.
The rhythm method and FAM also don’t protect against STIs. But, you can use them with condoms to protect against STIs and lower the risk of pregnancy even more. Other kinds of birth control like the pill, IUDs, and condoms tend to be better at preventing pregnancy. They’re also better at preventing pregnancy when people make common mistakes. If you want to use the rhythm method, you can use it at the same time as you use other birth control methods. Because the rhythm method is all-natural, it doesn’t conflict with using condoms, birth control pills, or an IUD.