Fertility awareness (natural family planning)

Fertility awareness (also known as natural family planning) helps you to identify which days during your menstrual cycle you are fertile and can possibly get pregnant. It can be used as a form of contraception or to increase your chances of conception.

After ejaculation, sperm can live in the body for up to 5 days. After ovulation, the egg released survives for only 12 – 24 hours. Therefore, you are most likely to conceive on the 5 days preceding ovulation, and the day of ovulation itself.

Your body temperature and cervical mucus change throughout the menstrual cycle. Monitoring these changes can help you identify when you are nearing ovulation . Avoiding sex on the days that you are most fertile reduce your chance of becoming pregnant. Having sex on these days maximises your chance of conceiving.

There are a few methods you can use to practice fertility awareness:

• symptothermal method
• ovulation method
• periodic abstinence
• cervical mucus method or Billings method
• rhythm method

Fertility awareness only works as a method of contraception if you and your partner agree to follow the instructions very carefully. Since you can get pregnant for a few days before and after you ovulate, you need to be very careful not to have sex on these days.

Fertility awareness is not suitable if:

• you have just stopped using a hormonal method of contraception, such as the pill
• you have irregular periods
• you are approaching menopause
• your partner doesn't agree to use this method

The advantages of using fertility awareness as contraception include:

• It's natural with no known side effects.
• You may get to know your body and menstrual cycle better.
• It's free.
• It's reliable, if used correctly.
• It can be a good alternative if you cannot or do not want to use other methods of contraception for religious, cultural or health reasons.

Here are some disadvantages of using fertility awareness as contraception:

• Fertility awareness does not protect you from sexually transmitted infections (STIs). You will need to use other forms of contraception, such as condoms, to protect against STIs.
• Illness and vaginal infections can affect your mucus and body temperature, making it difficult to track your fertility.
• You are more likely to become pregnant using fertility awareness than other methods of contraception.
• It can take between 3 – 6 cycles to learn to correctly identify your fertile days in a menstrual cycle.
• You will need to pay attention to daily physical changes in your body throughout your cycle.
• Fertility awareness requires long periods of abstinence every month.

There are different ways to use fertility awareness to avoid pregnancy:

Cervical mucus method or Billings method

Your cervical mucus changes throughout your menstrual cycle. There are 3 distinct consistencies of mucus during your cycle:

1. Right after your period — your vaginal opening may feel dry, and the mucus may feel flaky and/or sticky.
2. Around the time of your ovulation — the mucus's texture is like raw egg whites and may become clear, more watery and elastic.
3. After you ovulate — the mucus becomes cloudy, thicker and sticky.

You can use the changes in your cervical mucus to identify when you are ovulating. You are recommended to avoid sexual intercourse until after you have had 3 consecutive 'dry' days.

Being sexually aroused or having semen in your vagina can make it hard to identify the consistency of your cervical mucus.

This method isn't suitable if you have abnormal bleeding from your vagina or inflammation in your cervix or vagina. It can also be affected by certain medicines which can change your cervical mucus.

Temperature method

Your resting body temperature rises slightly by 0.2 – 0.5°C after you ovulate, and remains elevated until your next period.

This method involves measuring your temperature with a thermometer at the same time every day, immediately after waking up and before you get out of bed. You must measure your temperature in the same location (vagina, rectum or mouth) each time.

Your fertile window ends when your temperature has risen for 3 days in a row.

This method isn't very accurate because many other factors can affect your body temperature including:

• illness
• sleeping more or less than usual
• alcohol
• stress

It also means you may need to abstain from sex for many days in the month.

Symptothermal method

This method combines 2 or more signs of fertility such as measuring your body temperature and keeping track of your mucus secretions to calculate your fertile days in your cycle.

Combining different methods of fertility awareness makes it more likely to be effective at preventing pregnancy.

Calendar or rhythm method

This method involves calculating your fertile days based on your fertile days in previous months. While this method can be easier to use than monitoring your body for signs of ovulation, it can be quite unreliable. It's also not suitable for people who have irregular periods.

You can find more information about how to use calendar-based methods at Family Planning NSW (Opens in new tab).

• You can read more about fertility awareness (Opens in new tab) at Family Planning Australia.
• Visit Sexual Health Victoria to learn more about different methods of contraception (Opens in new tab).
• Play Safe has information about having safe sex (Opens in new tab).