A chart and digital thermometer

Fertility awareness (natural family planning) is a way of predicting which times of the month a woman is more likely to get pregnant if she has unprotected sex. 

Women learn how to monitor signs of fertility, such as body temperature, cervical fluid, and calculating the length of the menstrual cycle. 



  • It helps women understand their own bodies better
  • It’s hormone free
  • It’s acceptable in most religions and cultures
  • There are no side effects
  • Can be useful when trying to become pregnant
  • There’s no need for medical checks, although to work best it should be taught by a specialist


  • It can be tricky to learn
  • It takes a few months to monitor the patterns
  • Quite a high risk of pregnancy
  • Daily monitoring is needed (temperature, vaginal fluid)
  • Illness, stress or travel might make it hard to interpret records
  • Unprotected sex should be avoided on the most fertile days
  • Both partners need to be committed to using this method

There are apps available

Some apps to tell you when it's safe to have sex - most commerically available have never been properly tested and so should be used with caution. Fertility awareness is most reliable if you monitor several different things - basal temperature, cervical fluid, and cycle pattern. 

If you're keen to avoid hormones, contraception methods like the copper coil or diaphgram might suit you. You can still have skin to skin contact with a partner with these methods.

What's right for you?

Good to know

It requires quite a lot of dedication and attention to detail to be able to rely on fertility awareness for contraception. 

How much effort is Fertility Awareness?

Women need to pay close attention to their bodies and its patterns. They record body temperature first thing in the morning, cervical fluids, and work out when they are likely to have released and egg (ovulated) based on the length of their cycle. Body temperature and fluid at the cervix changes depending on where a woman is in her cycle, and therefore whether she can get pregnant if she has sex at that time.  Fertility awareness is more effective when all of these methods are used together.

A woman needs to take these measurements over a period of time before she can start to predict her more or less fertile days.  If a women’s periods are irregular, or if she has recently stopped using a hormonal method of contraception, it takes longer for her to be able to predict her fertile times accurately. 

There are apps and fertility charts that can help track the changes and help to chart the more fertile and less fertile days. 

Male partners are also involved, since they will probably need to use condoms or avoid penetrative sex at some times of the month . 

How effective is Fertility Awareness?

Generally, it is not as effective as hormonal or long-acting methods of contraception. 

When used perfectly, feertility awareness is between 99 and 91% effective, meaning that if 100 women 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 average user can expect it to be around 85% effective, meaning that if 100 women used natural family planning for a year, around 15 of them would become pregnant. 

How does it work?

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

What's right for you?