How will summer holidays affect my measuring?

Off on your summer holidays and wondering how it might affect your measuring? Here’s a look at the top questions we get on measuring your temperature and using the Natural Cycles app from our Cyclers who are heading overseas.

Can I still measure my temperature if I’m traveling abroad to another time zone?

If you travel across several time zones and experience jet lag then we recommend skipping measuring (or tap Deviating temp.) for 1-2 days upon arrival and departure, until your body has adjusted and you have had a good nights rest. After you have adjusted to the new time schedule, you should measure as usual when you wake up in the morning, around the same time and in the new time zone.

Can warmer weather affect my basal body temperature?

 The answer is no, not significantly. Your body is very good at regulating its’ optimal temperature as humans are warm blooded animals. Also, we do recommend you to measure under your tongue, with your mouth closed. Measuring on your skin or in the ear, can be affected by the outside factors such as room temperature or your clothes etc. which is why you shouldn’t do so.



What about late nights? 

Remember to always skip measuring or tap ‘Deviating temp.’ if you feel hungover or if you have slept less than usual. We know those summer nights can sometimes be endless 🙂 

Can I use the app offline? 

Unfortunately, you can’t use Natural Cycles offline at the moment. We are however working on making these improvements in the future, it’s a little more complex as the algorithm runs on our servers and you require an internet connection to get a result. More on that here.  You can take note of your temperature and add it later on when you have a connection again, just remember to check your status for the day every morning.


It’s also good to know that traveling can be stressful on the body, which means that it can sometimes affect your cycle causing, for instance, a delayed ovulation, shorter or longer cycles or in some cases anovulatory cycles.

Read more about how traveling can affect your cycle


Hope you can make great use of this info,

Your Natural Cycles team

Birth Control is About Life Control

Natural Cycles found that birth control choices are based on a poor understanding of how the body and contraception works. The campaign #LifeChangingOptions hopes to improve awareness around contraception so that couples find a method that suits both of their needs entirely and bolsters their ability to prevent pregnancies.

As part of the campaign, Natural Cycles asked 3000 men and women across the UK, US and Sweden, basic knowledge questions about reproduction and contraception that the company considers necessary to prevent pregnancies effectively. Study participants were asked about their contraception use, their feelings towards them as well as the science behind pregnancy. 

The survey results show the general public’s understanding is lacking, with only half of all questions answered correctly. The UK’s awareness was lowest, at 45 percent, followed by the United States, 50 percent, and finally Sweden, the home country of Natural Cycles came out top with 54 percent.

When asked, nearly 30 percent of women on the pill do not know how the method works and 52 percent failed to answer pregnancy-risk related questions correctly. Furthermore, almost 80 percent of these women say they would prefer to use a natural method of contraception but results suggest that they are held back by their general lack of awareness.

It is part of women and men’s reproductive rights to understand the options that are available to them to prevent unwanted pregnancies. A privilege that we take for granted, which is upsetting if you consider that millions of girls in the developing world have no access to contraception whatsoever.

For every use of the hashtag #LifeChangingOptions, Natural Cycles will donate a condom to developing countries to try and institutionalise the concept of “choice” by expanding options so that underprivileged girls can take control of their own future.

And of course, if you would like to become one of our Cyclers, sign up here!


Test your knowledge by watching this video:

How did you do?

1. How does a women get pregnant?

A: To put it simply, an egg is released from the ovaries and a sperm fertilises an egg


2.  How long can sperm survive in the female body?

A: Up to 5 days 


3. Can a woman get pregnant any time in her cycle?

A: No, a woman can only get pregnant during ~6 days of her cycle.

Here’s the equation: 5 day sperm survival + 1 day egg survival = 6 day fertile window


4.  So when do you think are you most fertile?

A: For an optimal chance of conception, sperm should already be present in the fallopian tube before the egg is released, which means the most fertile day of the woman’s cycle is rather the day prior to ovulation than the day of ovulation itself.


5. How does the pill work?

A: The pill has a few of lines of attack: a) Stops ovulation so there is no egg to fertilise, b) changes the lining of the uterus  so an embryo cannot implant in the womb c) thickens the cervical mucus so it is harder for sperm to penetrate the womb and reach the egg.


6. Do you know how your temperature changes during your cycle and how this information can be used to track your fertility?

A: Women’s resting body temperatures rises once they have ovulated (0.2-0.45 C).  Ovulation marks the end of fertile window, which indicates a woman has entered her infertile phase. Temperature can therefore be used to find which phase a woman is in her cycle, informing her when she is fertile and is not fertile.

Screen Shot 2015-08-27 at 17.41.27

For more information about tracking your cycle please visit our support portal, Ask Tibi.

Yours naturally,

The Natural Cycles Team


Does travelling affect basal temperature accuracy?

Midsummers marks the beginning of the holiday season, which means lots of us will be travelling to our favourite holiday destinations to get some much needed Vitamin D – especially those of us living north of the equator where the summer still hasn’t arrived!

The thought of hotter climates has led many of our Cyclers to become a little hot-headed about their favourite travel essential, NaturalCycles, who have asked the question ” does travelling affect basal temperature accuracy? “. So we thought it would be helpful to answer a couple of your questions so you can relax wholeheartedly and enjoy the sun!

A common question is whether resting temperature is affected by a hotter climate?  The answer is, not significantly, as your body is very good at maintaining itself at it’s optimal and by measuring your temperature under your tongue – not on the skin or in the ear – it means that your reading is not greatly affected by the surrounding room temperature.

In fact, the main reason for temperature fluctuations when travelling abroad often comes down to quality of sleep. The warmer weather and different time zone can often mean a disturbed night. It’s either too humid or too cold – depending on whether you’ve opted for AirCon – and trying to become attuned to a new ‘bed time’ can take a couple of days. So as a guideline, we say that it’s always best to skip a measurement or two during this changeover period. Moreover, the suggested guideline for jet lag recovery rate is one day per time zone, so as a rule of thumb, you might want to try skipping one measure day per time zone to get optimal results. 

The next query that comes hand-in-hand with holidays is measuring the morning after drinking. We recommend Cyclers to skip measuring if you feel hungover or if you have slept less than usual but if you have had one cocktail whilst watching the sunset you will be OK to measure!

If you have any more questions please leave a comment or get in touch via

Your NaturalCycles Team

How can your doctor use NaturalCycles to help you?

Is your doctor or nurse unsure how to use NaturalCycles? Well, we’re here to help you, help them make the most out of our service. Why?  Because information about your unique cycles could help medical professionals answer important questions associated with your reproductive and sexual health.



Dr. Who

Accurately tracking menstruation and ovulation, provides powerful information. For instance:

– Period and ovulation tracking, could help diagnose and/or manage conditions like PCOS, a endocrine system disorder that can affect both of these cyclical events.

– Tracking menstrual cycle characteristics can help understand a woman’s fertile potential and odds of conceiving on a cycle-to-cycle basis.

– Specific information about a woman’s cycle, such as PMS symptoms that women can enter in ‘Notes’, can also help a physician make a diagnosis or evaluate treatment for endometriosis, a condition that affects the tissue lining the uterus.


Fertility tracking with NaturalCycles can also help determine:

– If a woman is pregnant,

– When exactly she got pregnant and therefore improve predictions for due dates

– Offer insights into the health of the fetus in the first trimester.

FACT:  Did you know that NaturalCycles notifies a user to seek medical advise if the algorithm captures low temperatures at the early stages of pregnancy? This is because low temperatures indicate insufficient progesterone levels to support the early development of a fetus.


The information medical professionals can obtain from a user’s calendar and statistics are as follows:

– Number of anovulatory cycles

– Average ovulation day and variation

– Cycle regularity

– Cycle length and variation

– Phase length (Follicular and Luteal)

– Temperature in each phase

– Cover line temperature

– Temperature fluctuations

– Time and length of menstruation



















If you have any further questions or want to share your experience we’d love to hear from you so please comment or get in touch via

Yours naturally,
The NaturalCycles Team



Switching from Hormonal Contraception to NaturalCycles

Many of our cyclers recently quit hormonal contraception and have many questions in regards to this. Here is a short summary that answers some of them.

How does hormonal contraception affect your body?

For a woman to become pregnant, she has to ovulate. Once the ovulation has taken place, the egg can be fertilized. Hormonal contraception, in general, prevents pregnancies by preventing ovulation.

Once you’ve quit hormonal contraception, it may take a while before your ovulation kicks back in, and your natural menstrual cycle. This is completely normal, especially after many years of hormones.

As a woman can only get pregnant during ovulation, NaturalCycles’ algorithm works by finding the woman’s ovulation day. Once the egg is released, it can survive up to 24 hours, and during this time it can get fertilized. As sperm can survive up to 5 days in the woman, NaturalCycles gives you red days at least 5 days before expected ovulation, during ovulation day, and 24 hours after the egg is released. If NaturalCycles’ algorithm does not know you well yet (i.e. you have not yet had a detected ovulation) – few green days will be given.

When do I start measuring?

Ideal is to start measuring with NaturalCycles a few days after stopping your hormonal contraception. That way we will not miss your first ovulation! Don’t measure while still on the hormones, as these hormones affect your temperature.

Have a little patience…

Once you start measuring, it can take up to 6 months for your cycle to get started again and this might lead to many red days. As your ovaries have rested for such a long time (especially after many years of hormonal contraceptives), it may take a while for ovulation to kick back in. This is very normal and nothing to worry about, but please do have patience with the enlarged amounts of red days if this happens to you. Your ovulation can happen at any time and safety is what comes first to us.

It is therefore important to have a little patience in the beginning. For each and every day you measure, NaturalCycles gets to know you better and better. Soon you will be able to enjoy having full control of your natural cycles and get a balance in your red and green days. As a Plan-user, you have full control of your fertile days, and as a Prevent user, you are protected naturally, without side effects!

The NaturalCycles team






Continue reading

To measure or not to measure, that is the question?

A question that often pops up from Cyclers relates to how they can optimise their morning temperature measuring routine. To help, we thought we would create a quick guide of all the the do’s and don’ts.


Always measure first thing in the morning, before you get out of bed in the morning.

Always measure underneath your tongue so that the metal point sits at the root of it.

For the first 3 cycles, try to measure as often as possible.

For the 5 days before and after expected ovulation, try to measure almost every day.

Disable temperatures if they seem abnormally high due to being sick or a change in routine: Long sleep-ins, drinking heavily, late night, slept badly.

Do not:

Do not measure on sick or hangover days as this will give you more red days than necessary.

Do not measure once you’re up and out of bed as this reading will not be your resting temperature (BBT).



Here are also some tips from some of the Natural Cycles team, that might help you make your own routine:


“If I slept really badly the night before and wake up feeling tired, my temperature is higher than usual so I usually give it a miss for the day.” Dani, Cycler for 4 months 


“I often don’t measure on weekends because I love my lie-ins.” Elina, Cycler for 3 years (TIP: don’t measure if you wake up >3 hours earlier/later than usual)


“I tend not to measure on days when I don’t follow my normal ‘weekday’ routine, which means late nights and drinking.’ 

Eliza, Cycler for 5 months (TIP: don’t measure if you get more than 2 hours more/less sleep than usual )


“Whenever I travel to a different time zone, I tend to skip the first morning as it means I slept more/less than usual.” Nicole, Cycler for 1 year


So ladies, I think that is about it. If you follow these guidelines then you should get a nice temperature curve, like the one below:

Our cycles should roughly take a sinne curve shape

Our cycles curve usually have a ‘Sine’ shape


Just remember that there will of course be some fluctuations that cannot be avoided, but this is normal so no need to worry!

One final thought, please try not to bias your graph by picking and choosing on a regular basis, if you do have data points that you are unsure about then just get in touch as we are here to help! Email


Happy measuring!

Key facts about Endometriosis

Next week is Endometriosis Awareness Week (2-9th March) so we thought it would be a useful exercise to educate the Cycler community about the condition so you all know what to look out and are able to can keep a check on your health.

First, let’s start with the basics. Your endometrium is the lining of blood that builds up on the uterine walls every cycle due to your bodies natural hormonal changes. If no egg implants into the endometrium, it will break down and become your period. However, if it is fertilised, the endometrium grows thicker and protects and nourishes the growing foetus.

Healthy reproductive anatomy

Healthy reproductive anatomy


What is Endometriosis?

Endometriosis is where the lining of blood is also found outside your uterus. Areas that are most commonly involved are your ovaries, bowel or the tissue lining your pelvis.




During the menstruation stage of your cycle, endometriosis cells react similarly to your healthy endometrial cells because hormones also stimulate them to grow, break down and bleed. This therefore causes internal bleeding that can lead to irritation, inflammation, pain, and the formation of scar tissue (adhesions).  Learn more here.


Key facts:

  • 10% of women worldwide have endometriosis – that’s 176 million worldwide (Ref. 1)
  • The prevalence of endometriosis in women with infertility be as high as to 30–50%.2 (Ref. 2)
  • On average it takes 7.5 years from onset of symptoms to get a diagnosis. (Ref. 3)
  • The cause of endometriosis is unknown.
  • Currently, there is no way of preventing endometriosis but there are ways of managing symptoms and the disease.



Symptoms of endometriosis vary during the menstrual cycle, where they are often worse on the days before and during your period.

Endometriosis symptoms include:

Screen Shot 2015-02-26 at 15.26.18

Figure sourced from Endometriosis UK


If you have a combination of these symptoms it is important that you book an appointment with your GP for a check-up right away.




  1. Rogers PA, D’Hooghe TM, Fazleabas A, et al. Priorities for endometriosis research: recommendations from an international consensus workshop. Reprod Sci 2009;16(4):335-46.
  1. Meuleman C, Vandenabeele B, Fieuws S, Spiessens C, Timmerman D, D’Hooghe T. High prevalence of endometriosis in infertile women with normal ovulation and normospermic partners. Fertil Steril 2009;92(1):68-74.
  2. Diagnosis Survey. Endometriosis UK. February 2011.



Test your knowledge: are you a NaturalCycles pro?

Today is an exciting day as we now have more than half a million days of data from all our Cyclers! This means we have been able to apply this knowledge to making the algorithm even better at adapting to your specific cycle and isolating the fertile window. Hurray!


We thought a great way to celebrate this time point would be to see how Natural Cycles has helped women understand their bodies better. Aside from improving women’s health, one of our main priorities is to better educate the public about fertility so that women are able to make more informed decisions about their choice of contraception.



So here are some questions with varying levels of difficulty to see where you stand on the fertility whizz chart.  Are you a Pro Cycler or Novice?


  1. For how many days in total are women fertile throughout their cycle?
  2. How long can sperm survive within a woman’s body?
  3. What causes your resting temperature to rise after ovulation?
  4. When is the best time to measure your resting temperature (BBT)?
  5. What name is given to the phase in your cycle when you are mostly fertile?
  6. Can you get pregnant if you have sex on your period?













  1. Up to 6 days when you take sperm survival into consideration.
  2. Up to 6 days too. Did we catch you out? 😉
  3. A surge in progesterone that is associated with the start of the luteal phase.
  4. First thing in the morning before getting out of bed.
  5. The follicular phase. This is when you have the fewest green days because it is before ovulation. The luteal phase is post-ovulation and before your period starts.
  6. It’s not likely, but it can happen, especially if a woman’s menstrual cycle is short. In a 20-day cycle, for example, ovulation could occur on day 8 of her cycle then her period would begin on Day 1 and last for about 5 days. However, as you know (or have just learnt) a man’s sperm can survive in a woman’s body for up to 6 days. This means that if a couple has unprotected sex during her period then the sperm still has a chance to fertilise the egg and cause pregnancy.


What does a positive LH test mean?

“I took an LH-test which showed positive, however, Natural Cycles indicated that my ovulation day was in fact later than this?”

We’ve got the answer to the question you’ve all been asking:

The hormone LH actually rises before ovulation and does not indicate the day of ovulation. So while you might have a positive LH test, it does not indicate that you have ovulated, nor that you are ovulating at this very moment.

A positive LH test is rather an indication that ovulation is about to occur.

That’s why an ovulation test can be positive a few days before ovulation up until the day of ovulation. The algorithm takes LH tests as indicators into account, yet the temperature shift indicates and verifies that ovulation has indeed occurred. Sometimes LH tests can give what is called a false-positive. This means that even if the test indicates that your body is experiencing a rise in LH, it doesn’t actually mean that ovulation is going to happen within the next day or so as you’d expect. And to note, this can be especially true and common if you have Polycystic Ovaries Syndrome (PCOS). In these cases, NaturalCycles will not agree with the ovulation test because a rise in LH before ovulation has to also accompany a rise in temperature after ovulation. This is why combining both ovulation tests and temperature is such a powerful combination because together they confirm that ovulation has definitely occurred.

Your Natural Cycles team.

Things you need to know about LH tests!

Do you have irregular cycles? Or have you just quit the pill? You might want to combine measuring your temperature with LH tests that are now from our webshop:


What is LH and why test for it?

LH stands for Luteinizing Hormone and appears for about 48 hours and is shortly followed by ovulation. You can read more here if you are interested in the science of fertility.

If you have irregular cycles then we highly recommend testing for LH. If you have recently been on hormonal contraception, it is likely that your cycle will be out of balance and irregular for up to a year. This is very individual and is taken into account by NaturalCycles’ clever algorithm, which will be even more cautious if this is the case.

It is not necessary to test LH if you do not want to, but it is a powerful supplement to the basal body temperature to indicate when ovulation has occurred. Temperature measurements have day-to-day fluctuations, which can make it challenging to identify the exact ovulation day quickly – the more data entered the easier it becomes! However, positive LH tests can help speed things up and give you more green days quicker.


2. How do I know when to test for LH?

As a woman’s LH surge happens just before ovulation, NaturalCycles will recommend that you to check LH levels a couple of days before the expected ovulation. How far in advance you need to start testing depends on how regular your cycles are.

Depending on whether you use the website or the app, the LH reminder looks a bit different. On the website, you can hover over the calendar with your mouse and you’ll see a reminder in red, for instance on the day before predicted ovulation. On both the website and the app, you’ll see “LH” with an arrow pointing at the day of the week that you should measure on, and you will also see that the the LH field will be pre-opened on the ‘add data’ window.  Additionally, on the app you will see a “Today!” notification next to the LH entry field for the day that you should test on.




Or in the app:




Please get in touch if you have questions about LH or anything else!
Have a nice thursday!

Lots of Love

NaturalCycles Team