Natural family planning – how does it work and is it right for me?

22nd September, 2022 • 11 min read

Want to find out more about natural family planning? This type of natural contraception, also called the fertility awareness method, may suit you if you’re looking for alternatives to the contraceptive pill because of side effects or to condoms if you’re allergic to them – or you just want to feel closer to your partner.

Read on to find out how natural birth control works, the pros and cons and how effective it is at preventing pregnancy.

What is natural family planning?

Natural family planning or (the fertility awareness method) is a

natural form of birth control
that’s all about getting in touch with your body and keeping track of your unique fertility signals.

Natural contraception is a method couples often use if they’re comfortable with the risk of pregnancy, despite not actively trying to have a baby.

The idea is to work out when your fertile window is – a period of about 7 to 9 days – when your chances of conceiving are higher than at any other time in your cycle. It means the method can be used as birth control (although it’s not as reliable as other methods), but also as a way to increase your chances of getting pregnant, if that’s what you want.

Find useful information on other areas of getting pregnant with our

complete Guide

How does it work?

Get in touch with a qualified fertility awareness teacher if you live in the

, or a fertility awareness instructor if you’re in the
to make sure you’re following the method properly. They’ll be able to guide you through the 3 key steps of the natural birth control method, answer any questions you might have and help you make a note of any changes you see.

There are plenty of apps you can use to track your fertility signs, but if you’re someone that prefers to write things down manually, try downloading a

free fertility wall chart

Should you use the 3 fertility steps together?

Yes! There are things that can affect each of these checks individually, so the ideal is to learn about all 3 and use them together.

Following all 3 steps accurately every month acts as a triple check that your fertile time is when you think it is, which will increase the effectiveness of natural family planning.

1. Calculate how long your menstrual cycle is

Working out how long your period lasts for, when you’re coming up to ovulation and when you ovulate is really helpful for understanding when your fertile window is and how long it lasts for. It’s also a great way to learn more about your body in general.

So, how exactly do you count the days of your menstrual cycle? Keep these points in mind:

  • day 1 is the first day of your period
  • ovulation
    (when an egg is released from your ovaries) happens somewhere in the middle of your cycle, 10 to 16 days before your period starts. This is your fertile time – you can get pregnant up to 5 days before ovulation and for around 2 days after you ovulate, if you have sex. This is because sperm can live inside a woman's body for up to 5 days and fertilize the egg when it's released
  • the last day of your cycle is the day before your next period begins
  • the average cycle length is around 28 days, but anything between 21 and 40 days is healthy and very normal

Once you know how long your cycle is you can work out when you tend to ovulate and when your fertile window might be. Avoiding unprotected sex during this period can reduce the chances of getting pregnant.

Bear in mind that your ovulation time can change, especially if your periods aren’t regular or you bleed between periods, and it can also be affected by lifestyle factors like stress or illness, so this method isn’t always reliable in stopping you from getting pregnant.

Remember to keep track of how long your cycles are – recording your last 12 cycles will give you a much more reliable picture. If they vary in length, this method can help you work out your fertile days:

  • subtract 20 days from your shortest cycle to estimate the first fertile day
  • subtract 10 days from your longest cycle length to estimate when your last fertile day

So for example, if your shortest cycle is 26 days and your longest is 32 days, your fertile window would be from days 6 and 22 so you’d need to avoid sex or use another method of birth control to prevent a pregnancy.

2. Monitor your cervical mucus (vaginal discharge)

You might notice changes in how your cervical mucus (or vaginal discharge) looks and feels at different times of the month – this is different for everyone and it can change from cycle to cycle.

Monitoring this every day can be a great way to understand where you are in your menstrual cycle, and you can do it by checking your panties when you go to the toilet, or by gently placing your middle finger into your vagina and pushing it up to around your middle knuckle.

Below are the little signs you should look out for:

  • after your period finishes your vagina will feel a bit dry for a few days and there won’t be much, if any, discharge
  • in the lead up to ovulation your cervical mucus will become moist, sticky, white and creamy. This is the start of your fertile window. You’ll want to avoid having unprotected sex from the time you first notice this sticky cervical mucus until your period
  • just before ovulation your cervical mucus will get heavier, wetter, clearer and more slippery (a bit like raw egg white), which means you're at your most fertile time
  • after ovulation the mucus will get thicker and stickier again, which often signals that you’re coming out of your fertile window

Be aware that certain lifestyle factors can affect the amount and texture of your cervical mucus, including the use of medication, feminine hygiene products, douching, sex, breastfeeding, or having a pelvic exam where lubrication is used. This is why it’s a good idea to use more than one birth control method at the same time and not rely on just your cervical mucus to predict your fertile window.

3. Take daily temperature readings

Just after ovulation your body rises in temperature slightly (around 0.2C or 0.4F), so checking your basal body temperature (BBT) every day can be another way to check your fertile time.

How to get it right:

  • you’ll need to use a digital thermometer to take your BBT
  • this needs to be done at the same time each day, before you get out of bed in the morning, or after at least 3 hours of rest, and before you eat or drink anything
  • once you notice 3 days in a row of higher temperatures than the previous 6 days in your cycle, you can be pretty sure you’ve ovulated and are no longer fertile
  • remember that the difference in these temperatures will be very small – only about 0.2C (0.4F)

Things you need to know

Your BBT can also be affected by things which might make the readings less reliable. These include:

  • illness
  • stress
  • taking painkillers
  • drinking alcohol
  • oversleeping.

This is why using the temperature method on its own is not enough to predict your fertile window.

What other natural signs of fertility should I look for?

Are you someone that notices mild pain 2 weeks before your period (

ovulation pain
) and changes to your boobs, skin, mood or sex drive (libido) at certain times in your cycle?

Most women notice an increase in their sex drive in the days before ovulation, when there is a higher chance of getting pregnant, because of a spike in the hormone oestrogen. This can make you more interested in sex than at other times in your cycle.

These signs and symptoms can be another helpful way of confirming when you’re in your fertile window, alongside monitoring your BBT, cervical mucus and your cycle length, but they shouldn’t be used as a form of contraception on their own.

How effective is natural family planning?

Natural family planning is around 76% effective with typical use – 24 in 100 women using it will get pregnant in a year. But if all instructions are followed exactly, with the help of a fertility awareness specialist, the natural family planning method can be up to 99% effective. This means 1 to 9 women in 100 who use it will get pregnant in 1 year.

To make it 99% effective you have to carry out all the steps properly, as well as avoid unprotected sex during a time when your sex drive (libido) is likely to be at its highest.

What are the advantages of the fertility awareness method?

Some advantages of using this natural method as a form of contraception are that you:

  • can also use it to understand your body better and be more aware of your fertility cues
  • can use it to reduce the risk of pregnancy but also to increase the chances of having a baby
  • don’t have to take any chemicals such as hormones, or use physical devices such as
  • won’t get any physical side effects
  • can get to know what’s normal and what’s not normal for you when it comes to
    vaginal discharge
  • it can be used by most faiths and cultures
  • can use it for free or for very little cost, compared to other birth control methods
  • can involve your partner in the process, which can help increase feelings of closeness and trust

What are the disadvantages of the fertility awareness method?

It’s important to be aware of the downsides of the method and understand that it isn’t as reliable as other forms of contraception. These disadvantages incvlude:

  • you’re not protected against
    sexually transmitted infections (STIs)
    , such as
  • you'll need to avoid sex, or use contraception such as
    , during your fertile time, which you might find difficult. If you choose to avoid sex completely during this period, your fertile window might be up to 16 days, depending on your cycle
  • it’s much less effective than other methods of contraception, if the steps are not followed accurately
  • it can take 3-6 menstrual cycles for you to learn all the steps, and before you become confident in working out when you think your fertile time is. So for 6 months it’s recommended that you use barrier methods like condoms when having sex
  • you need to keep a daily record of your fertility signs, which can be time consuming
  • stress, illness, travel, lifestyle and hormonal treatments can disrupt your fertility signs, which can make it harder to know exactly when you ovulate
  • if you’ve recently stopped using hormonal contraception like the
    birth control pill
    , or you’ve needed to use the
    emergency contraceptive pill
    , you should wait until 2 complete menstrual cycles have passed before using the method reliably again

Who shouldn’t use natural birth control?

Natural contraception is not right for every woman and should be used with caution if you have any of the following:

  • irregular periods
  • you don’t get periods (complete amenorrhea)
  • you’ve just started your period
  • you have bleeding between periods that’s difficult to distinguish from your normal menstrual period or makes assessing your cervical mucus difficult
  • you are not able to avoid sex or use a barrier method during your fertile days
  • becoming pregnant would be a health risk to you
  • you’re approaching

When to see a doctor about natural family planning

You should always speak to a doctor before starting any new form of contraception. They can help you work out if natural birth control methods, like the natural family planning method, are right for you and your partner.

They might refer you to a fertility awareness instructor to help you with this, or encourage you to get checked for STIs at a sexual health clinic, before having unprotected sex.

And if you decide natural family planning isn’t for you, a doctor can help you find other

contraception options
that might suit you better. If you decide to use this method and notice you miss your period, it’s important to do a pregnancy test to check for pregnancy.

Important: Our website provides useful information but is not a substitute for medical advice. You should always seek the advice of your doctor when making decisions about your health.