DIY guide to fertility awareness
This is my long Do It Yourself guide to using fertility awareness as contraception.
If you want something shorter, start here. If you want something longer, or different, skip straight to the resources and references at the end of this page.
Sexual health charities recommend you get support (from someone like me) before using fertility awareness to avoid pregnancy.
If you want something shorter, start here. If you want something longer, or different, skip straight to the resources and references at the end of this page.
Sexual health charities recommend you get support (from someone like me) before using fertility awareness to avoid pregnancy.
Is fertility awareness for you? It could be if...
- You are aged 18 to 44 years old. Your cycles are usually fairly settled at this time of your life - unless you are breastfeeding, or have an underlying health issue. You can use fertility awareness if you are older than 44 but it might be more difficult.
- You have periods (true periods not pill periods). They don't have to be every 28 days, you just need to get them - preferably every 21 to 35 days.
- You can handle your fertile days. That means using condoms or other precautions for about 10 days a month. It will be longer than this while you are learning, or if you have very irregular cycles. You should of course use condoms if there is any chance of getting a sexually transmitted infection.
- You can record a few things. Mainly day one of your period, your waking temperature and your maximum fluid days (usually two or three a month). There is a limit to how much information you need, but it is also important that...
- You notice things. This means illness, sudden stress (good or bad), or taking your temperature an hour or two earlier or later than usual. These can all have an impact on your cycle. If you notice them you can allow for them and make adjustments and allowances.
- You can learn a few things. Mainly how to spot a sustained rise in your waking temperature - and those maximum fluid days. There is a limit to how much you need to learn.
Cycle basics - amber days, red days, green days.
Your fertility cycle (or menstrual cycle) starts on day one of your period and ends the day before your next period begins.
An average cycle lasts 28 days but cycles vary from month to month and from woman to woman. We are not machines.
An average cycle lasts 28 days but cycles vary from month to month and from woman to woman. We are not machines.
Your fertility cycle has three parts - amber (relatively infertile), red (fertile), and green (infertile) days.
Amber days
Your amber days start on day one of your period.
To start with, assume you can get pregnant from sex on your amber days.
Pregnancy is less likely than on your red days but it is possible - especially if you have any cycles than last less than 26 days.
To start with, assume you can get pregnant from sex on your amber days.
Pregnancy is less likely than on your red days but it is possible - especially if you have any cycles than last less than 26 days.
Red days
After your amber days you get nine red (fertile) days - when sex could lead to pregnancy.
You are most likely to get pregnant on just two or three of your red days - the days before and during ovulation.
But you need to use precautions on all nine days if you want to avoid pregnancy.
You are most likely to get pregnant on just two or three of your red days - the days before and during ovulation.
But you need to use precautions on all nine days if you want to avoid pregnancy.
Green days
Finally, you should have a block of between six and twelve green (infertile) days.
Green days occur when you confirm that ovulation has been and gone.
You can't get pregnant if there isn't an egg about - or due to be released sometime soon.
Green days occur when you confirm that ovulation has been and gone.
You can't get pregnant if there isn't an egg about - or due to be released sometime soon.
Don't assume your green days have begun because your period is due, or your app says you're infertile.
Take your time.
Gather your fertility awareness kit, record your data, and know what to do with it.
Take your time.
Gather your fertility awareness kit, record your data, and know what to do with it.
Your fertility awareness kit
Paper charts
Yes, I know. What year is this?? What about apps?
Go with it, at least to start with. It's easier to use paper charts while you're learning.
You can shift to an app-only approach once you know what you're doing.
Here's one for you to download:
Yes, I know. What year is this?? What about apps?
Go with it, at least to start with. It's easier to use paper charts while you're learning.
You can shift to an app-only approach once you know what you're doing.
Here's one for you to download:
A thermometer
A basic fever thermometer is fine. You don't need two decimal points, they overcomplicate things.
Two decimal point thermometers - basal body temperature or BBT thermometers - are used because there is sometimes a dip in your temperature just before, or as, you ovulate, but this is not reliable and you can go cross-eyed looking for it.
As Jane Knight says, "look for the rise, not the dip".
Also this guide is about avoiding pregnancy, not getting pregnant. If you want to get pregnant, read this.
I recommend this iProven thermometer because it's fast and quiet.
Before you ask, you stick it in your mouth. Dig it in under your tongue, close your mouth and breathe through your nose.
If you don't sleep well, consider buying "TempDrop" - you strap this on your arm overnight and enter the data into an app.
An app (or two)
I suggest either Ovuview (Android only) or Kindara. For Ovuview, click on the top left menu, select methods, then deselect all of them except Rule R (Rotzer).
You can also use Clue - just because it is so lovely and clear to use.
Read more about apps and monitors here.
A basic fever thermometer is fine. You don't need two decimal points, they overcomplicate things.
Two decimal point thermometers - basal body temperature or BBT thermometers - are used because there is sometimes a dip in your temperature just before, or as, you ovulate, but this is not reliable and you can go cross-eyed looking for it.
As Jane Knight says, "look for the rise, not the dip".
Also this guide is about avoiding pregnancy, not getting pregnant. If you want to get pregnant, read this.
I recommend this iProven thermometer because it's fast and quiet.
Before you ask, you stick it in your mouth. Dig it in under your tongue, close your mouth and breathe through your nose.
If you don't sleep well, consider buying "TempDrop" - you strap this on your arm overnight and enter the data into an app.
An app (or two)
I suggest either Ovuview (Android only) or Kindara. For Ovuview, click on the top left menu, select methods, then deselect all of them except Rule R (Rotzer).
You can also use Clue - just because it is so lovely and clear to use.
Read more about apps and monitors here.
Recording your data - keep it simple
You can record more than this if you like, but the essentials are:
Day one of your period
That means the first day of fresh, red blood - enough to need a tampon, pad or menstrual cup.
Start a fresh chart every time your period starts.
Filling out the top of your chart is probably the most time-consuming thing you will do all month. It takes about two minutes.
Here's an example:
- Day one of your period
- At least ten waking temperatures (enough to confirm your temperature shift)
- The two or three days when you have lots (and I mean lots) of vaginal fluid
Day one of your period
That means the first day of fresh, red blood - enough to need a tampon, pad or menstrual cup.
Start a fresh chart every time your period starts.
Filling out the top of your chart is probably the most time-consuming thing you will do all month. It takes about two minutes.
Here's an example:
Record your period using the fluid boxes at the bottom of your chart. Day one is already filled out.
If you get spotting (tiny amounts of blood) before or after your period, use a star:
Record day one of your next period on the same chart (and on a fresh chart).
Doing this helps you work out your cycle length (this one was 29 days long).
Waking temperature (Basal body temperature)
This means your resting temperature. Not your "just used the bathroom" temperature, or your "just had a drink of water" temperature, or your "just had a quick chat" temperature.
Take your temperature after at least 3 hours of sleep, at roughly the same time each day (give or take 30 mins) and before you have a drink or get out of bed.
There's no need to wake up properly. Just turn on your thermometer, shove it in under your tongue, breathe through your nose, and turn it off when it beeps.
When you're ready, turn the thermometer back on to read the temperature - that's what the memory function is for.
Record it on your chart with a dot in the relevant box, and on your app, and join up the dots.
You should end up with a line on your chart that looks something like this:
Doing this helps you work out your cycle length (this one was 29 days long).
Waking temperature (Basal body temperature)
This means your resting temperature. Not your "just used the bathroom" temperature, or your "just had a drink of water" temperature, or your "just had a quick chat" temperature.
Take your temperature after at least 3 hours of sleep, at roughly the same time each day (give or take 30 mins) and before you have a drink or get out of bed.
There's no need to wake up properly. Just turn on your thermometer, shove it in under your tongue, breathe through your nose, and turn it off when it beeps.
When you're ready, turn the thermometer back on to read the temperature - that's what the memory function is for.
Record it on your chart with a dot in the relevant box, and on your app, and join up the dots.
You should end up with a line on your chart that looks something like this:
If you forget to take your temperature, don't join up the lines. It makes missed days easier to spot.
If your temperatures look very up and down check your technique is right - shove it in under your tongue and breathe through your nose.
If you breathe through your mouth at night, try closing your mouth for a minute before you take your temperature. This can help ensure a correct reading.
What if you wake up earlier or later than usual?
If you wake up more than 30 minutes earlier or later than usual, note what time you took your temperature so you can adjust it.
Your temperature is lowest at about 4am and goes up 0.1 degree celsius per hour after that. Move it up one box (0.1 degree) for each hour you earlier than usual, and down one box for each hour later than usual.
In other words, move it up if you got up earlier and move it down if you lay down for longer.
Fluid
Noticing your vaginal fluid when you use the bathroom helps you tell how fertiile you are.
It might seem alarming but it does not have to be a big deal. You don't need a speculum. You don't need to check every day of your cycle, and you don't need to stick your fingers inside your vagina.
All you need to do is notice whether there is any fluid when you wash yourself in the shower or when you wipe after using the toilet.
You're looking out for the days when you get lots (and I means lots) of clear(ish), thick and stretchy fluid that looks like raw egg white.
These are your maximum fluid days. You should get two or three of these days in a row each cycle.
Maximum fluid means maximum fertility so be extra careful with your precautions, or get busy if you want to get pregnant.
Don't assume you are infertile because you don't see any fluid.
It is still possible to get pregnant when you have very little fluid about. Some women don't have an obvious fluid pattern.
Use both fluid and temperature to check your fertility.
Record your fluid using the boxes at the bottom of your chart.
If your temperatures look very up and down check your technique is right - shove it in under your tongue and breathe through your nose.
If you breathe through your mouth at night, try closing your mouth for a minute before you take your temperature. This can help ensure a correct reading.
What if you wake up earlier or later than usual?
If you wake up more than 30 minutes earlier or later than usual, note what time you took your temperature so you can adjust it.
Your temperature is lowest at about 4am and goes up 0.1 degree celsius per hour after that. Move it up one box (0.1 degree) for each hour you earlier than usual, and down one box for each hour later than usual.
In other words, move it up if you got up earlier and move it down if you lay down for longer.
Fluid
Noticing your vaginal fluid when you use the bathroom helps you tell how fertiile you are.
It might seem alarming but it does not have to be a big deal. You don't need a speculum. You don't need to check every day of your cycle, and you don't need to stick your fingers inside your vagina.
All you need to do is notice whether there is any fluid when you wash yourself in the shower or when you wipe after using the toilet.
You're looking out for the days when you get lots (and I means lots) of clear(ish), thick and stretchy fluid that looks like raw egg white.
These are your maximum fluid days. You should get two or three of these days in a row each cycle.
Maximum fluid means maximum fertility so be extra careful with your precautions, or get busy if you want to get pregnant.
Don't assume you are infertile because you don't see any fluid.
It is still possible to get pregnant when you have very little fluid about. Some women don't have an obvious fluid pattern.
Use both fluid and temperature to check your fertility.
Record your fluid using the boxes at the bottom of your chart.
Make your final egg white day obvious by filling out all the boxes above the final egg white box to make a bar, like this:
Tip: You can stop recording fluid once you have had four days without egg white.
Comments
Record anything that might affect your temperature or your cycle length in the comments section under each cycle day, or in the space on the left of your waking temperature.
This includes taking your temperature earlier or later than usual, illness, medication, and any major events (good or bad) that might have caused unusual stress. This could be anything from running a marathon to grief over a lost friend or family member.
You can also record things that might be linked to your cycle, like period pain, breast pain, energy, mood or skin changes.
Tip: If you want to record more information, you could use the Fertility UK chart, which this chart is based on.
Comments
Record anything that might affect your temperature or your cycle length in the comments section under each cycle day, or in the space on the left of your waking temperature.
This includes taking your temperature earlier or later than usual, illness, medication, and any major events (good or bad) that might have caused unusual stress. This could be anything from running a marathon to grief over a lost friend or family member.
You can also record things that might be linked to your cycle, like period pain, breast pain, energy, mood or skin changes.
Tip: If you want to record more information, you could use the Fertility UK chart, which this chart is based on.
How to identify your green days
Your green days begin once your temperature goes up, and stays up, AND the amount of fluid you produce goes down, and stays down.
The day your green days begin will change from cycle to cycle. It doesn't matter if your cycles are irregular - you can still use fluid and temperature to confirm that your green days have begun.
Remember to use precautions on your amber and red days - and to be extra careful on your maximum fluid days.
The day your green days begin will change from cycle to cycle. It doesn't matter if your cycles are irregular - you can still use fluid and temperature to confirm that your green days have begun.
Remember to use precautions on your amber and red days - and to be extra careful on your maximum fluid days.
Your temperature goes up...
Sometime after cycle day eight, there should be a shift from lower to higher temperatures on your chart.
- Wait to see if you have three days in a row of higher waking temperatures.
- Check that these three days follow six lower temperatures - you only need six, ignore any high temperatures at the beginning of your cycle.
- Check that the third higher temperature day is at least 0.2 degrees celsius higher than the previous six days.
- Green for go! Your green days start on the evening of the third higher temperature day.
Your temperature will usually drop on the day that your next period starts, or the day after.
If you have eighteen or more higher temperatures you are probably pregnant and should take a test.
Tip: you could skip taking your temperature until day six of your cycle. This can can help you avoid confusing high temperatures at the beginning of your cycle.
If you have eighteen or more higher temperatures you are probably pregnant and should take a test.
Tip: you could skip taking your temperature until day six of your cycle. This can can help you avoid confusing high temperatures at the beginning of your cycle.
AND your fluid goes down...
The amount of fluid changes through your cycle.
This is the pattern to look out for. It's not always this simple but it can be:
This is the pattern to look out for. It's not always this simple but it can be:
Lots of fluid means you are very fertile so be careful with your precautions.
You are also fertile before your maximum fluid days because your body produces hang-around fluid which can keep sperm alive for up to seven days.
Your first higher temperature should always be before your final egg white (maximum fluid) day. If it isn't, wait another day.
You can assume you are infertile if your temperature stays high and you have had 3 days without egg white - and you're not sick.
You are also fertile before your maximum fluid days because your body produces hang-around fluid which can keep sperm alive for up to seven days.
Your first higher temperature should always be before your final egg white (maximum fluid) day. If it isn't, wait another day.
You can assume you are infertile if your temperature stays high and you have had 3 days without egg white - and you're not sick.
How does this look on your chart?
Don't force it!
Your temperatures and fluid might not follow the standard pattern. If that happens, assume you are fertile for the whole cycle.
This is why it is important to be comfortable with how you handle your fertile days.
This is why it is important to be comfortable with how you handle your fertile days.
When do your red days begin?
The early days of your cycle are only ever amber (relatively infertile) because it is difficult to predict when ovulation will occur and sperm can survive for as long as seven days.
But if you record your cycle length and temperature, you can use your data to work out when your red (fertile) days begin.
This is about combining your data with the evidence about sperm and egg life.
It about extremes not averages - your average cycle length doesn't matter, your shortest cycle does. Your average temperature shift day doesn't matter, your earliest temperature shift day does.
The same applies to sperm and eggs. Average sperm life doesn't matter - the super-strength sperm that lasts 7 days does. Average egg life doesn't matter - the two-egg ovulation that leads to 48 hours of egg life does.
You can back up this fluid checks - you assume that you are fertile as soon as any fluid appears.
But if you record your cycle length and temperature, you can use your data to work out when your red (fertile) days begin.
This is about combining your data with the evidence about sperm and egg life.
It about extremes not averages - your average cycle length doesn't matter, your shortest cycle does. Your average temperature shift day doesn't matter, your earliest temperature shift day does.
The same applies to sperm and eggs. Average sperm life doesn't matter - the super-strength sperm that lasts 7 days does. Average egg life doesn't matter - the two-egg ovulation that leads to 48 hours of egg life does.
You can back up this fluid checks - you assume that you are fertile as soon as any fluid appears.
How to use cycle length to work out your first fertile day
If you have any cycles less than 26 days long your fertile (red) days start on cycle day four.
If all your cycles are 26 days or longer your first fertile day is day six. You can also use these calculations:
If you have six months of data:
Shortest cycle in last six months minus 21 = first fertile day
e.g. 29 - 21 = day 8 is your first fertile day
If you have a year of data:
Shortest cycle in last year minus 20 = first fertile day
e.g. 29 - 20 = day 9 is your first fertile day.
If all your cycles are 26 days or longer your first fertile day is day six. You can also use these calculations:
If you have six months of data:
Shortest cycle in last six months minus 21 = first fertile day
e.g. 29 - 21 = day 8 is your first fertile day
If you have a year of data:
Shortest cycle in last year minus 20 = first fertile day
e.g. 29 - 20 = day 9 is your first fertile day.
How to use waking temperature to identify your first fertile day
Your earliest temperature rise day is a more precise way to work out your first red (fertile) day.
This means the cycle day on which your temperature shifted from lower to higher - the first of the three higher temperatures.
This is always sometime after cycle day 8. You need a year of data to do this.
Here's the calculation:
Earliest temp rise day in last year minus 7 = first fertile day
e.g. Cycle day 16 – 7 = day 9 is first fertile day
If you want to be extra cautious, you can add an extra day, so:
Earliest temp rise day in last year minus 8 = first fertile day
e.g. Cycle day 16 – 7 = day 8 is first fertile day
This means the cycle day on which your temperature shifted from lower to higher - the first of the three higher temperatures.
This is always sometime after cycle day 8. You need a year of data to do this.
Here's the calculation:
Earliest temp rise day in last year minus 7 = first fertile day
e.g. Cycle day 16 – 7 = day 9 is first fertile day
If you want to be extra cautious, you can add an extra day, so:
Earliest temp rise day in last year minus 8 = first fertile day
e.g. Cycle day 16 – 7 = day 8 is first fertile day
Want some help?
This guide is not intended to replace getting support. Talking things through is generally easier and more effective.
Check out my services page if you want support from me.
Check out my services page if you want support from me.
Resources and references
- The fpa's guide to natural family planning
- Fertility UK website, especially Getting Started
- The Complete Guide to Fertility Awareness. Jane Knight. Authoritative textbook for anyone interested in fertility awareness, especially researchers, academics and health professionals. Jane Knight runs Fertility UK.
- Taking Charge of Your Fertility. Toni Weschler. Bestselling US fertility awareness book. Massive, but very helpful and readable. Buy the print version so you can make the most of the illustrations.
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