How to calculate your ovulation?
When trying for a baby, you probably ask yourself every cycle ‘when will I ovulate’. You can use an online ovulation calculator or ovulation calendar to calculate your ovulation date, but these just ask you to input your average cycle length. They will probably place your ovulation date around 14 days before your next period is due or halfway through your cycle which may be fine for many women. It is not helpful however, for women with irregular cycles or for women with longer or shorter than average luteal phases. The only reliable way to calculate your ovulation date and to predict when you may next ovulate is to chart your cycles.
What do you need to chart your ovulation?
Firstly, you need to buy a digital thermometer. We sell ovulation thermometers here at My Fertility for just £3.49p . They measure to 2 decimal places which is highly desired when charting your ovulation. This is because we are trying to detect small changes in your body temperature throughout your cycle and a thermometer that only detects to 1 decimal place may cause you to miss this temperature rise. You can pay securely through Paypal.
Secondly, you need to download a fertility app on your phone which allows you to chart your temperatures. I tried quite a few apps but the one I use and prefer is called Fertility friend. You can download the app on your phone for free but you can also update and view your charts and ovulation calendar on their website from your computer. Their free version of the app is basic but is more than adequate.
How to chart your ovulation?
How to take your temperature.
Oral temperatures should be more than adequate when charting your ovulation. Oral temperatures however may be affected by environmental conditions such as a cold bedroom, or whether you have been breathing with your mouth open or closed when you were asleep. You can take a few steps to get the most accurate temperature. Ensure you do not drink any hot or cold drinks before inserting it into the mouth and you should keep your mouth closed for a few minutes before inserting the thermometer and measuring. Once you have inserted the thermometer, wait for a minute or so. The thermometers give a little beep once they have finished measuring your temperature.
Arm pit temperatures are quite unreliable so you should measure using oral temperatures from day one. You may also take your temperature anally or vaginally which give readings much closer to your core body temperature and a much smoother chart. There is however a risk of causing trauma and introducing infection into the vagina if the thermometer is not inserted very carefully or not cleaned thoroughly after use. I therefore suggest you take your temperatures orally.
When to take your body temperature?
To determine when to take your body temperature we need to discuss what happens to your temperature throughout the day and night.
When you wake up in the morning after at least 6 hours of sleep, your body temperature is close to its lowest point for that day. Your body has been resting and you have not been carrying out any physical activity. Once you get up and start to move around, have your breakfast and get ready for your day, your temperature will start to increase and it will be at its highest from late morning until the evening if you remain active. This is because when your body is active it produces heat.
In the late evening, your body starts to prepare you for sleep and as this happens your body temperature will start to slowly drop again. Once you are in bed and you start to feel relaxed and sleepy, your body temperature can be just as low or even lower than what it was first thing that morning. Your body temperature will remain low throughout the night.
So when should you take your temperature to chart ovulation?
You need to record the lowest body temperature for that day and it is advised to take your temperatures’ first thing in the morning, when you have just woke up. You should take your temperature as close to the same time as you can so if you wake for work at 6-7am, take it at 6-7am every morning before you get out of bed. If you take your temperature within half an hour or so of your chosen time then you should be fine. Taking it at 8am or 9am will make a difference however, even if you have just woken up. Your body temperature will naturally start increasing around this time. If you forget to take it one morning then don’t worry about it. The next few days of temperatures’ will fill in the blanks. There is a website that allows you to adjust your temperatures if you woke up later or had to get up earlier than your usual time, which I used sometimes but it isn’t really necessary.
When in your cycle to start charting your temperatures’?
I would advise to start to input your daily temperatures at the beginning of your cycle after your period has finished, which is normally around cycle day 5 or so. These temperatures’ before ovulation will be your pre-ovulation temperatures’ and your baseline. After a few cycles you will be able to see a clear range of temperatures’ that your pre-ovulation temperatures’ stay within e.g. my pre-ovulation temperatures’ range between 36.1 and 36.5 degrees Celsius. I find it useful to visually see the cover line that fertility friend draws on my charts. It allows me to see the limit that my pre-ovulation temperatures should stay under and what my post-ovulation temperatures should stay above.
How long after ovulation does your temp rise?
This depends on the individual but usually you will see your temperature rise a little the day after ovulation and more so from 2 days after ovulation has taken place.
What is a cover line?
When I talk about my cover line, this means the line drawn horizontally on my chart set at the highest pre-ovulation temperature that I get i.e. around 36.5 degrees Celsius. This can be adjusted if you think that fertility friend has made a mistake by going into the setting section on the phone app and into detector override. You can change the detector from ‘advanced’ to ‘manual’ and input a different temperature for your cover line. Now and again my pre ovulation temperatures’ rise above 36.5, but once I know I haven’t ovulated I discard them on the app in the ‘primary’ data section in the app.
What if you haven’t had a period since stopping the pill?
If you have come off the pill and haven’t had a period since (after your withdrawal bleed) then start charting your temperatures’ straight away. If you come on within a week or 2 after you start then it is likely that these initial temperatures’ will be your post ovulation temperatures’ and you can start again with the lower temperatures’ from cycle day 5 or so once your bleeding has stopped.
How to use Fertility Friend?
If you have joined fertility friend, then you can set up your account by inputting the date of your last period and your average cycle length. You can then start to input your daily fertile signs and morning temperatures’. When you click on a date it will go to the data entry section which allows you to input your ‘primary’ data which include your body temperature for that day and the time you took it, your cervical mucus (fluid) type, whether you have any bleeding and to what extent and whether you have had sex that day. If you are monitoring your cervix (opening size, feel and height) you can input this data in the ‘secondary’ signs section.
The ‘tests’ section allows you to input if you have got a positive/negative ovulation test and if you use a ferning microscope you can input whether you have seen full, partial or no ferning (see ovulation tests section for more information’. You can also input if you get a positive or negative pregnancy test.
The ‘specific’ section lets you record any other signs that you have such as ovulation pain, cramps, fatigue, bloating etc.
The ‘meds section lets you input any fertility medications or herbs you are taking.
This is all I use this app for but you can also upload photos and share them on the forums and ask for help from other ladies on there.
How to tell if you have ovulated?
A day or so before you ovulate, you will get an increase in luteinizing hormone which will give you a positive ovulation test if you use them. As luteinizing hormone levels increase it reaches its threshold level and an egg is released. Once the egg is released, your levels of progesterone will start to increase which warms the body. Once you have ovulated you should see a rise in your basal body temperature (BBT) on your chart. You need to see at least 3 high temperatures’ above your pre-ovulation range (or cover line) for 3 consecutive mornings to confirm ovulation. They should then stay high until your period arrives or until you give birth, if you are lucky enough to fall pregnant.
How does Fertility Friend confirm your ovulation?
The day that you ovulate will be the last day your temperatures’ will be below your cover-line. After 3 days of higher temperatures’, fertility friend will draw a red line vertically on your chart to signify this. The line may be dotted if the App is not 100% sure that you have ovulated on that day. If the line is solid, then it is pretty confident that is your ovulation date. The more signs you input e.g. your type of cervical mucus and your ovulation test results, the more certain you can be about your ovulation day. Your temperatures’ should slowly increase over the first 5-7 days as your progesterone levels reach a peak and then the curve should flatten out. Your temperature will remain high until your progesterone levels drop again the day you get your period. The number of days from ovulation to your period represents your luteal phase length and this should be between 12 and 16 days. If it is less than 12 days long and you have some spotting for several days before your period comes, then you may have a luteal phase defect. See the section on ‘luteal phase defect‘ for more information on this.
What can affect your body temperatures’ and mess with your chart?
There is a lot of information online about charting your ovulation using your temperatures’ and most of it states that you must take your temperature before you pee, move, stand up, brush your teeth etc as any movement will raise your temperature. I have done some experiments with this and it makes no difference really. If you take your temperature after you have been to the loo as you forgot to do it straight away then don’t worry. I have actually taken my temperature and then got up and gone downstairs to make a cuppa and then took it again and it was actually lower the second time. It is more important to take your temperature at the same time of day, every day. Once you get to know your cycles and your pre and post ovulation temperature ranges, you will know if you have done something wrong and whether to discard certain temperatures’.
Alcohol – Drinking alcohol the night before can raise your basal body temperature (BBT) and affect your charting. I don’t mean a glass of wine here, I mean getting drunk and being hungover in the morning. Any temperatures’ that are particularly high the morning after a heavy night drinking should probably be discarded.
Late night – Along with drinking alcohol, having a late night and less than 6 hours of sleep can affect your temperatures’. Once again, discard any temperatures’ that are particularly high and do not coincide with your fertile signs and ovulation tests if you are using them.
Disturbed sleep – If you have been tossing and turning all night then your temperature in the morning will probably be above your coverline making things a bit confusing. To get around this read the tips section below (Tips to confirm ovulation).
Illness – This is an obvious one. If you are poorly you will probably have a raised body temperatures’ or slight fever which can mess up your chart, especially if you ill for a few days. This is a difficult one if you are ill around the date you should ovulate. It is more reliable to check your other fertile signs such as cervical mucus or do an ovulation test.
What if you work night shifts?
This will be about trial and error for you as an individual. The annoying part is when you are flipping from working to not working. If you sleep from 8am to 3pm in the afternoon and take your temperature at 3pm after you have woken up, your temps may be low. On your days off you should take your temperature in the morning after you have woken up. This will at least mean you are taking your temperatures when they should be at their lowest in the day. I would experiment however and see what works for you.
Temperature drop before ovulation.
Some women see their basal body temperature (BBT) drop before ovulation and I get this on my charts often. The day before I ovulate my temperature is usually lower than it has been for a few days. This is due to the surge in the hormone estrogen before ovulation, which lowers your body temperature. In addition, your BBT during ovulation can be quite low too. This is really helpful when trying to analyse your charts as the increase in BBT after ovulation should be very clear.
Tips to confirm ovulation if your chart is confusing.
What taking your temperature at night can tell you?
Firstly does your temperature stay high at night. After you get into bed (after 10.30pm is best) and start to relax and feel sleepy take your temperature. If it is below your cover line on your chart then it is unlikely that you have ovulated yet or maybe you have but only a day or so ago. Any high temps on your BBT chart may be red herrings. If your temperature stays high above your cover line once you are relaxed and sleepy in bed then you have more than likely ovulated. You can double check this if you wake up in the middle of the night and take your temperature. Before you ovulate your temperatures’ overnight will be below your cover line but after you have ovulated they will stay above your coverline. From 2-3 days after ovulation, your BBT will stay high 24hrs a day until your period comes.
Combine all of your fertile signs with your chart data.
You need to combine all your fertile signs and ask yourself it they fit in with what your chart is telling you. If your temperature has risen for a few mornings above your cover line but you have not experienced any of your normal fertile signs (such as a change in your cervical mucus to the fertile type or your ovulation tests have been negative), then it is likely that you have not yet ovulated and your temperatures’ are higher for another reason e.g. you may be coming down with a cold.
Can you tell from your ovulation chart that you are pregnant?
Your temperatures’ stay high and your period doesn’t arrive.
If you know the length of your luteal phase then you can be pretty sure that you are pregnant if your temperatures’ stay high for a few days after your period is due e.g. If you know your luteal phase is the average 14 days long and you know which day you ovulated on from your chart, it is more than likely that you are pregnant if your temperatures’ have stayed high for 16 days or more and your period does not arrive. This is because your luteal phase length stays pretty consistent from cycle to cycle so you should come on your period a set number of days after you have ovulated.
N.B. Your luteal phase can change in length from one month to the next if e.g. you are stressed, you have lost weight or if you are taking Vitamin B6 or fertility herbs.
An implantation dip is when your body temperature drops or dips for one day during your luteal phase. If it is truly an implantation dip then it occurs around the time that implantation would occur i.e. 7-10 days or so after you have ovulated. If you are charting your temperatures’ and you see your temperature drop lower than your current post ovulation temperatures’ or even below your cover line it could be an implantation dip and a sign that you are possibly pregnant. It is caused by a surge in estrogen which briefly lowers your body temperature. On the Fertility Friend gallery, ovulation dips are seen on around 20% of charts that end in pregnancy compared to around 10% of charts that do not end in pregnancy. Although this can be a sign of pregnancy, do not think that because you have one on your chart that you are pregnant and vice versa. Do not assume that because you have not seen one that you are not pregnant. I have been pregnant 4 times and have never seen an implantation dip on my chart.
How many days after ovulation can you take a pregnancy test?
If you really want to take a pregnancy test before your period is due then I would wait until at least 12 days after ovulation. I have had a positive pregnancy test at 10, 11 and 12 days after ovulation but they were very faint. With my daughter I didn’t get a positive pregnancy test until 13 days after ovulation, so it does vary for the individual women and the individual pregnancy. To prevent disappointment and a wasted test, wait until at least 14 days after ovulation to test. The levels of the pregnancy hormone doubles each day so the difference a few days can make is huge.
My fertility friend ovulation charts.
Below are a dozen or so examples of my BBT charts with a short explanation below each one.
More charts to come.