What Is Natural Family Planning?

Natural family planning is a type of pregnancy prevention method that relies on recording the body’s fertility signs and abstaining from intercourse or using a barrier method during your potential fertile windows. Sometimes referred to as “fertility awareness,” natural family planning can also be used to achieve pregnancy, since it can help you understand which days of the month you are most fertile.

This method is often appealing to people who would rather go a more natural route when it comes to birth control, people whose religion prohibits other methods, or people who’ve had negative side effects from other forms of birth control.

About 1% of couples in the U.S. use this method. It’s important to understand that natural family planning is one of the least reliable forms of birth control: its real-life failure rate is about 24%.

Here's a closer look at natural family planning, including the different methods available, the risks involved with this method, and other available forms of birth control.

What Is Natural Family Planning?

Natural family planning is based on the idea that there are only certain days of your menstrual cycle where it’s possible for you to conceive. In an average menstrual cycle, an egg is released about midway through (usually about 14 days after your last period, on a 28-day cycle). That egg lives for about 12-48 hours. Additionally, sperm is able to survive in your reproductive tract for about 3-5 days.

The period of time when you are able to conceive is called your “fertile period” and experts agree that you are fertile for about five days before you ovulate and for about one day after. Natural family planning involves learning more about your cycle, tracking your fertility, and recording your fertility “signs” such as chances in your cervical fluid and body temperature.

There are four basic methods used to track fertility signs. These include the standard days method (or calendar method), the cervical mucus method, the basal body temperature method, and the symptothermal method.

Standard Days Method

Also known as the “calendar method,” the standard days method relies on period tracking to determine your fertile days, and requires you to avoid intercourse during those days. According to the American College of Obstetricians and Gynecologists (ACOG), if you have a cycle anywhere between 26 and 32 days long, your fertile days are days 8-19 of your cycle.

To avoid pregnancy, you’d need to abstain from intercourse during those days. The Standard Days Method is only meant for people who have regular and predictable menstrual cycles that average 26-32 days long.

Cervical Mucus Method

This method relies on changes in your cervical fluid or vaginal discharge to determine your fertile periods. If you track changes to your discharge, you may notice that in the middle of your cycle, right before ovulation, your discharge becomes more plentiful and its consistency becomes slippery, like egg whites. After you ovulate, the fluid becomes thicker and less abundant.

The cervical mucus method requires you to avoid intercourse during the days when your fertile mucus appears.

Basal Body Temperature (BBT) Method

There are slight fluctuations in your body’s temperature during your menstrual cycle. During and after ovulation, your body temperature rises a small amount, about half a degree to one degree Fahrenheit.

The basal body temperature method requires you to record your temperature each morning before you get out of bed, using a basal body thermometer. You will know you’ve ovulated when your temperature rises; this rise is usually sustained, up until a day or two before your next period arrives.

This method is best used to understand your cycle, not to prevent pregnancy, as it can only tell you after the fact that you’ve ovulated.

Symptothermal Method

The symptothermal method combines several of the above methods to create a more detailed picture of your fertility. Usually, people combine the cervical fluid method with the BBT method.

Sometimes the use of an electronic fertility monitor or at-home ovulation detector kit is also used to maximize the data available to you about your fertility.

Does Natural Family Planning Work?

In general, natural family planning is not considered a highly effective way to prevent pregnancy. There are two ways that the effectiveness of this method is measured: perfect use and typical use.

Perfect use is when you employ the method as accurately as possible and that you use it regularly throughout your cycle. When used this way, only 1-5 out of 100 people will fall pregnant during their first year of using natural family planning.

But the numbers look different when you look at typical use for this method—meaning how this method is usually employed, which includes errors and a lack of consistency. When used in a typical manner, between 12-24 out of 100 people will become pregnant over the course of a year of use.

How to Do Natural Family Planning

If you are interested in natural family planning, you will need to familiarize yourself with your fertility signs. Depending on which method you use, you’ll need to track your menstrual cycles; check and record changes to your cervical mucus; and get a BBT thermometer and take your temperature upon waking.

Many people who employ this method also use at-home ovulation detector kits, which involve testing a urine sample for hormonal changes that indicate that ovulation is about to occur. Depending on the kit, the process is similar to using a pregnancy test.

These days, many people rely on fertility apps to track fertility. According to a 2022 study, there are over 500 such apps available today. The problem is that research has found that many of these apps are not reliable and don’t employ evidence-based fertility awareness methods.

However, there are two apps that have FDA clearance as contraceptive devices: Natural Cycles and Clue. If you have further questions about using an app as a contraceptive method, consider connecting with a healthcare provider.

Again, it’s imperative to keep in mind that whatever method you use to do natural family planning, the method has a high typical use failure rate.

Risks

Natural family planning doesn’t involve devices or medication, and is typically either free or low cost. But it’s also one of the least effective forms of birth control out there, especially when you look at typical use for the method. Besides that, as ACOG points out, natural family planning doesn’t protect you against sexually transmitted diseases or infections such as HIV.

There are certain individuals who should not use natural family planning. This includes:

• People who are at high risk of contracting an STD
• People who strongly want to avoid pregnant
• People who would have medical complications if they become pregnant

Furthermore, there are people for whom this method will not work, or will work even less effectively, such as:

• People who are close to menopause
• People in perimenopause
• People who have recently started menstruating
• People with irregular periods or who experience bleeding between periods, making it difficult to measure cervical fluid changes
• People who’ve recently weaned off of hormonal birth control or are on other medications that impact fertility
  

Other Forms of Birth Control

Natural family planning is not for everyone, especially someone who has a strong desire or need to avoid pregnancy. There are other, more effective methods out there. Connect with your healthcare provider to discuss the best method for. you.

Some options involve taking synthetic hormones, but others do not. Birth control options include:

• IUDs (intrauterine devices): hormonal and non-hormonal version available
• Hormonal methods, such as birth control pills, injections, implants, hormonal patches, and vaginal contraception ring
• Barrier methods, such as condoms, diaphragms, and sponges
  

A Quick Review

Natural family planning is a method of birth control involving learning your fertility signs and avoiding intercourse (or using a barrier method) on the days you’re fertile. Though the method sounds appealing to many—because it is free, natural, and doesn’t involve medication—its failure rate is high. The method should only be used by people who are okay with the possibility of pregnancy and understand its risks.

If you have further questions about this method, or want to find a birth control method that works for you, please get in touch with a healthcare provider to discuss options.