Fertility awareness (natural family planning) is a way of predicting ovulation, to work out when pregnancy is more likely

The method involves recording signs of fertility such as body temperature, thickness of fluid in the vagina, and calculating fertile times from menstrual cycle dates. 

Teaching from a qualified fertility awareness teacher is recommended.

Fertility awareness can be very effective (with daily monitoring)


  • Non-hormonal method
  • There are no side effects
  • The method involves learning how the body works
  • Skin to skin contact
  • Acceptable in most religions and cultures
  • Can be useful when trying to become pregnant


  • It can be tricky to learn, and takes a few months to monitor patterns
  • May have a higher risk of pregnancy
  • Daily monitoring is needed (temperature, thickness of fluid in the vagina)
  • Illness, stress or travel can make it hard to interpret records
  • More difficult to use if cycles become less predictable as you get older
  • Unprotected sex must be avoided on the most fertile days
  • No protection from Sexually Transmitted Infections
  • To work best it should be taught by a qualified fertility awareness teacher

Are mobile phone apps reliable?

Fertility awareness apps indicate likely fertile times. There are hundreds of apps for monitoring periods, but most apps are unregulated. 

To rely on fertility awareness, itis important to record two or more signs of fertility. For example, the Natural Cycles app records morning temperature as well as period dates. There has not yet been enough research to know how reliable this app is at preventing pregnancy.

Apps which only record period dates arte not reliable enough to be used for contraception (21% accuracy). This is because the time of ovulation can vary from month to month, and from person to person, depending on biological and lifestyle factors. To estimate the time of ovulation with accuracy, an app must have as much evidence as possible about the app user's period dates and other signs of fertility.

Apps are a really good way to learn more about your body and the menstrual cycle, but for pregnancy prevention, it is necessary to use one which records period dates and at least one more sign of fertility, such as temperature or vaginal fluid.

It is a good idea to discuss apps that you use for contraception with your doctor.

Which other methods are hormone-free?

If you're keen to avoid hormones, contraception methods like the copper coil or diaphgram might suit you.

What's right for you?

Good to know

Fertility awareness requires careful monitoring of the body's patterns. 

How much effort is Fertility Awareness?

Fertility awareness methods require close attention to patterns over time. 

Monitoring involves recording body temperature first thing in the morning, feeling the thickness of fluid in the vagina, and recording the pattern of periods, to work out when it is likely that an egg will be released (ovulation). Fertility awareness is more effective when two or more of these signs of fertility are monitored.

You need to record patterns for at least three months before starting to rely on predicting the fertile days. If periods are irregular, or if you have recently stopped using a hormonal method of contraception, it takes longer to be able to predict fertile times accurately. 

Fertility awareness does not work if hormones are taken at the same time, because the hormones will alter all of the signs of fertility.

There are fertility charts and mobile phone apps that can help track the changes and to predict fertile days.

To be effective, unprotected sex must be avoided around the most fertile days. This means typically avoiding unprotected sex for 8-9 days in a month, to allow for the time that sperm can survive, added to the time that an egg can survive.

How effective is Fertility Awareness?

Fertility awareness is generally not as effective as hormonal or long-acting methods of contraception. 

When used perfectly, fertility awareness is between 91% and 99% effective, meaning that if 100 people used fertility awareness for a year, between 1 and 9 of them would become pregnant. 

It takes commitment to use the method effectively, but it is a reliable method when used with attention to detail. However, allowing for the ups and downs of life, the method is around 76% effective, meaning that if 100 people used fertility awareness for a year, around 24 would become pregnant. 

How does it work?

Fertility awareness works by calculating when it's safer to have sex (when pregnancy is unlikely), and when to avoid penetrative sex or use another method (like condoms).

What's right for you?