An Honest Review of Fitbit for Menstrual Cycle Tracking

You may know that the Fitbit app has some built in menstrual cycle tracking features, but many people do not know that it has other features that may be useful for menstrual cycle tracking. In this article, I will review the pros and cons of the Fitbit app as it relates to cycle tracking for people who ovulate. For context, I use a Fitbit Charge III.

The most basic feature that Fitbit offers for cycle tracking is recording bleeding dates of menstruation and then displaying a predicted fertile window based on average cycle length.

The pink bar represents the length of menstruation. The blue bar represents a predicted fertile window. The flower symbol represents predicted ovulation.

The user needs to remember to input menstuation each cycle. Once it is inputted, Fitbit will generate the blue fertile window. This fertile window should NOT be used for avoiding pregnancy, as it is only based on cycle length and not real-time fertility signs like cervical mucus or basal body temperature.

Once menstruation is entered, it will also begin a countdown until your next predicted menstrual cycle.

Countdown until menstruation in the app.

Unfortunately, I do not find this basic feature very useful for anyone who has any cycle variation. Even though my cycle length has increased over the last year, Fitbit has not automatically updated my cycle lengths. The app does not appear to be very adaptive without user input.

In addition to tracking bleeding the app offers options for:

  • Mood
  • Plan B (morning after)
  • Ovulation tests (better called luteinizing hormone tests)
  • Cervical mucus (Taking Charge of Your Fertility categories)
  • Cyclical symptoms like acne

It is rather disappointing that the app does not include options to mark pregnancy when it occurs, especially since we know that this changes daily calories burned and heart rate, to name just two effected areas of the app.

A really cool feature that I do like is the ability to show cycle trends like flow intensity and cramps. The same screen that displays this will also let you scroll through all past cycle lengths.

In the settings of this screen, you can also decide to toggle off predictions. For people avoiding pregnancy, I do recommend either ignoring or toggling off predictions in the Fitbit app. The app allows you to choose your current birth control method as well.

Outside of the designed menstrual cycle tracking features, I want to highlight resting heart rate as a potential exciting thing to track for those who are not taking hormonal contraception. Why do you need to not be taking hormonal contraception to utilize the heart rate feature for menstrual cycle tracking? Hormonal contraception suppresses ovulation, and ovulation changes our heart rate charts!

To learn more about resting heart rate and the menstrual cycle, read my previous post here.

You can see my heart rate falling during menstruation around April 10th, and then rise during my fertile window and luteal phase.
Menstruation began when my heart rate dipped below 70 on this chart. Ovulation likely occured around the third raised heart rate in this close-up.

Heart rate in people who are ovulating is at its lowest point during menstruation, rises during the fertile window, and continues to be elevated in the luteal phase.

When heart rate begins to drop again, this is an excellent way to predict menstruation will soon occur. For example, I have been tracking my heart rate in Fitbit for 2 years, and I always bleed when my heart rate dips back down to 70 beats per minute after my luteal phase!

I do think this feature is worth tracking for anyone interested in a more precise period prediction than cycle length. If you have Fitbit premium, you can also find a setting for sleeping heart rate under restoration. This may be more steady than resting heart rate for some individuals.

Lastly, I want to address Fitbit temperature for menstrual cycle tracking. Unfortunately, wrist temperatures are not a compatible parameter for fertility awareness when it comes to avoiding or achieving pregnancy. It can be incredibly erratic. When we track temperature, we want the temperature as closest to the core as possible.

Fitbit does not give precise temperatures, instead it gives deviations from a range. I likely ovulated near 18, 19, or 20 on the photo above. While Fitbit did detect a slight shift, it is not particularly clear, and it dropped back down.

As depicted above, my luteal phase the previous month was extremely undefined, and I could not determine a confirmed temperature shift with it.

For now, I do not recommend Fitbit for precise temperature tracking. Instead, I recommend a basal body thermometer.

Conclusion

Fitbit offers some really unique options for cycle tracking, but it should not replace your birth control or fertility awareness method. The heart rate feature may be useful for identifying cycle phases, but the temperature readings are not suitable for tracking cycle phases.

An Honest Review of Kegg

For the last 5 cycles, I have been using the Kegg device that reads the electrolyte levels present in the cervical mucus in the vagina. To use this device, someone would insert Kegg in the same two hour period of time during the day. Kegg takes approximately two minutes to give the user a reading on the graph. Click here to read an article on the science behind Kegg.

This product is an exciting development in the femtech field because it actually does read a real-time fertility sign. Cervical mucus is completely necessary for natural conception to occur. Without the presence of cervical mucus in the cervical crypts, sperm cannot to get to their destination to reach the egg. For this reason, anyone trying to conceive needs to track cervical mucus or use an alternative device such as Kegg (or a device that reads estrogen levels) in order to time intercourse for when they are most likely to conceive.

Here is what a Kegg chart looks like while lined up with my real-time Billings Ovulation Method cervical mucus observations.

In this image, the three most fertile days with Kegg are represented by the three green bars. This lines up very well with my Billings Method observations. When reading a Kegg chart, you are looking for a set of high values – followed by a dip in the chart – followed by a rise.

Who is Kegg right for?

I know that the question on everyone’s mind is whether Kegg can be used to re-place cervical mucus observations for avoiding pregnancy. Unfortunately, the answer is that Kegg is not suitable for avoiding pregnancy. It is designed to find the most suitable days for conception. For those avoiding pregnancy, the fertile window has to be much longer than the window that Kegg gives. Until Kegg has been studied for pregnancy avoidance, I cannot recommend it as an alternative to cervical mucus checks which must be made multiple times of day until the evening when someone is strictly avoiding pregnancy.

Kegg may be right for someone who wants to conceive without needing to take a class or read a book on cervical mucus. In my experience, for the most part, it detected my most fertile days in a way that would likely lead to conception if used.

Kegg may not be right for you if you have a very erratic schedule. Since it has to be used in the same two hours and cannot be used up to 8 hours after sex, this may make Kegg harder to use. I personally experienced some issues timing Kegg correctly because of the nature of practicing a fertility awareness method meaning that I have sex at different times of the day based on what part of the cycle I am in.

Click here to purchase your Kegg!

My 5 Cycles with Kegg

The following images are my five cycles with the Kegg device compared to urinary hormones and cervical mucus observations. The three chicks in the egg represent the three most fertile days with Kegg. All of the charts are from Read Your Body by the Body Literacy Collective.

My Overall Impression of Kegg

I am often very critical of femtech that gives predictions, and Kegg does give calendar predictions at the beginning of the cycle. However, overall, I believe that the readings I got with Kegg did line up with my real-time signs for the most part. Since this device is for conception purposes, it does seem to highlight the most fertile days. I did have to switch from mornings to evenings on my Kegg readings to get clearer charts. I also find Kegg extremely hard to use in my luteal phase when sex may occur at any time of day, but this isn’t a huge problem since you can stop using Kegg once it has detected your rise. For those who want to add an extra layer to your chart or chart to conceive only, I can recommend the Kegg device.

Customer service with Kegg has been excellent. The team is very reachable. If you would like to see more Kegg charts and learn from fellow Keggsters, you may join the Kegg facebook group for conception or for those using it along with signs to avoid.

One Cycle Seven Ways: Experimenting with Marquette (Clearblue Monitor), Billings Method, Sympto-Thermal, Daysy, Kegg, DOT, and more!

Over the last several months, I have been testing multiple femtech products (such as Daysy Fertility Tracker, Kegg, DOT) and comparing them to charting methods like Marquette, Billings Ovulation Method, and Sympto-Thermal (NFPTA). These products and methods rely on different fertility signs such as basal body temperature, cervical mucus, urinary hormones, electrolyte levels, and calendar dates.

Disclaimer: Do not attempt to learn to chart using this post. My own experience may not reflect your unique cycles. My fertility intentions may not be your intentions.

Keep in mind that different methods may change safe days over time. The following data is only a snap shot of what fertility windows for avoiding pregnancy could look like. In particular, the Daysy thermometer only has 4 cycles of data on me.

Expected Consecutive Abstinence Over 3 Cycles

Cycle 52

  • Billings Ovulation Method: 15 (9 consecutive)
  • Marquette: 13
  • Sympto-thermal: 16
  • DOT: 12
  • Daysy: 15

Cycle 53

  • Billings Ovulation Method: 14 (8 consecutive)
  • Marquette: 13
  • Sympto-thermal: 13
  • DOT: 12
  • Daysy: 14

Cycle 54

  • Billings Ovulation Method: 16 (9 consecutive)
  • Marquette: 15
  • Sympto-thermal: 19
  • DOT: 12 (EXTREMELY RISKY)
  • Daysy: 15

From this data, you can see that sometimes the amount of expected abstinence does not differ from method to method, and sometimes it differs a whole lot! On my last cycle with DOT, it ended my avoidance window on the day after peak fertility occured. Fertility is still potentially high on the 3 days following this date.

Billings method almost always had the least consecutive abstinence because it relies on real-time fertility signs to open the window. However, because it rejects calculation rules and relies on one primary sign, only alternative evenings are ever allowed for pre-ovulatory sex. In addition, heavy days of menstruation are not allowed due to the possibility of early ovulation, and the bleeding obscuring the opening of the fertile window.

Other methods like Daysy, Sympto-thermal, DOT, and Marquette do allow pre-ovulatory consecutive sex, but most of that falls during menstruation for my cycle ranges (25 to 30 days).

Whatever method works best for someone is very dependent on their lifestyle and what someone is willing to diligently track.

The Same Chart Seven Ways

The highlighted days represent days to not use in order to avoid pregnancy with these methods.

My hearts are left on to show the fertile window and for authenticity. Do not use these charts to try to learn the rules of any method or to determine when sex is safe. You will see some broken rules based on my own personal intention level and on the fact that not all fertility signs will show the same window.

The Billings Ovulation Method draws the fertile window based on vulva sensation and cervical mucus. Any heavy bleeding is considered potentially fertile because it obscures readings and ovulation can always happen early. It requires alternating evenings for sex during the established basic infertile pattern.
This is the Marquette Method while using only urinary hormones and calculation rules. Fertile window opening determined by calculation rule based on last 6 cycles or first “H” reading on the Clearblue monitor. Clearblue measures estrogen and luteinizing hormone. My first window is also closed by a progesterone test in addition to meeting PPHLL rules.
This is the double-check sympto-thermal method per Natural Family Planning Teachers Association (NFPTA) rules. It opens the fertile window based on the shortest cycle in the last year minus 20. It closes the fertile window based on cervical mucus and basal body temperature.
This is a chart with the Daysy Fertility Tracker. This basal body thermometer learns your patterns over time and opens the fertile window based on past cycle data. The fertile window changes with time, and this is technically my 3rd Daysy cycle. Caution days and Red X days are for avoiding intercourse. Daysy does not allow the user to mark temperatures questionable, but I have marked two days questionable because I drank alcohol or had the heater on.
This example chart includes my cervical mucus notes for more context. DOT is a calendar based method that looks at the last 12 cycles of data. Only people in regular cycles can use DOT. Black moons are days available for intercourse based on the calendar method. In the next line, I also have included Kegg. Kegg predicts ovulation for trying to conceive purposes only, so I am including it as a bonus comparison. By reading the electrolyte levels in my cervical mucus, it determined that these 3 days were the most fertile days of the cycle. A full Kegg review is forthcoming in December 2020.
This is a resting heart rate chart. Resting heart rate has been shown to correlate with the menstrual cycle. I convert my heart rate like this: 69 = 96.9, 70 =97.0, 71 = 97.1, etc to be able to fit it onto the graph. You can see that it very closely followed my ovulatory pattern.
Here is my chart with all the data in one. It is so cool how different fertility signs draw the fertile window!

Unfortunately, my Mira Fertility sticks were flawed, so I had to remove that data from this experiment. In the future, I will do a comparison post also using this device. I am currently still testing the Kegg device, and a review with full Kegg charts is forthcoming in December. Kegg cannot be converted to display on the Read Your Body app, so I could only include the fertile days in this post.

Do you have any questions about all of these methods?

Consider coming to my free Instagram Live on femtech on November 28th. You can find me @chartyourfertility.

On December 12th, I’m offering a “pay what you can” introduction session that is minimum $5 to $30 USD on regular FABM methods and what the main differences are. Reach out to me if you would like to come.

Finally, a special shout to the Body Literacy Collective and the Read Your Body app for making this post possible by creating the most versatile charting app on the market!

Why You Should Be Cautious About Calendar-Based Methods (Daysy, Natural Cycles, DOT)

Calendar methods get a really bad rap in the fertility awareness communities. A lot of this is for a very good reason. When the calendar rhythm method was discovered in the 1930s, it was revolutionary. However, since then, we have discovered real-time fertility signs such as cervical mucus, basal body temperature, and urinary testing.

To illustrate why calendar-based rules can be both risky and occasionally line up with real-time signs, I charted with three calendar-based methods for opening the fertile window versus a method with real-time fertility signs only (specifically I used the Billings Ovulation method for my real-time method).

In the first line, you will see the Natural Cycles method. This method relies on basal body temperature as its only required real-time sign. Unfortunately, basal body temperature can only tell you when your fertile window closes, not when it opens. Temperature has no predictive qualities for letting you know if you are going to ovulate at a different time than normal.**

With only 3 cycles of my previous data, Natural Cycles gave me until day 8 as safe for this cycle. What Natural Cycles doesn’t know is that my cycles range from 24 to 30 days long over a calendar year. For this reason, it can be quite risky some cycles for me to be allowed safe sex until day 8. The fact that this cycle happened to line up is merely a coincidence! This coincidence can cause a confirmation bias when people use this app and do not get pregnant. If you are seriously avoiding, be wary of any method that doesn’t allow you to crosscheck the opening of your fertile window.

Natural Cycle also closed my fertile window in an incredibly risky manner. It told me I was safe on the morning after my real-time sign of “peak” day. In fertility awareness based methods, “peak” is the highest level of fertility you can get in a cycle. The two days following Peak day also have a significant chance of ovulation occurring. Every time I have used Natural Cycles (here is my previous try with it last year), it gives me a very risky closing to the fertile window.

Here is my full chart from Natural Cycles this time:

Natural Cycles app

Next up on the chart above illustrating my safe days is the Daysy thermometer. Daysy is a thermometer that relies on calendar based rules and potentially earliest temperature shift based rules to open the fertile window. In my two experiences with Daysy, it has been much more conservative than Natural Cycles. Daysy does learn over time, so it is possible I could have a risky day with it in the future, but so far I have not had any risky days with Daysy.

You can see in the image above that Daysy confirmed ovulation last out of all of the methods. I believe this is because my temperature shift was a bit erratic and because the device does not allow the user to mark temperatures questionable (I had two that were marked questionable for my own manual interpretation).

Daysy does not rely on anything except cycle length and temperature shift timing to open the fertile window. For this reason, Daysy can be risky if you ever have a very early ovulation. It can also be risky if the user is not careful about only taking their temperature when it is not disturbed, or if the device misreads a temperature shift. In my experience, Daysy tends to be much more cautious than Natural Cycles.

Daysy Chart

My third line is a true calendar only method. DOT has over a year of my data; however, the prediction has only given me one extra safe day during my whole use of the app. DOT is entirely based on the calendar method. However, interestingly DOT got higher efficacy than Natural Cycles in their study. Here is my DOT chart below

While I do not recommend the calendar method to most charters, this app can be useful for period prediction or for birth control if you are okay with an unintended pregnancy if you were to suddenly have a longer or shorter cycle. Users for DOT must have no more than 8 days variation in their cycle per calendar year.

In the example above, DOT actually gave me no risky days whatsoever. Again, this is a coincidence that it seemingly lined up with other signs. At any time, cycles can always change.

DOT the app

Finally, my main method is the Billings Ovulation Method. Billings relies only on real-time fertility signs. This means that they reject any calendar-based thinking, including the idea that menstruation is automatically safe. My Billings chart was based on when cervical mucus opened the fertile window (cervical mucus is what helps sperm survive) and when cervical mucus peak rules closed the window (when sperm can no longer access the cervix because ovulation is over and the cervical mucus plug has closed).

I always recommend real-time fertility signs to anyone who wants very high efficacy, the least amount of consecutive abstinence, who may be in regular or irregular cycles, and who want to understand their body and their health on a more deeper level. Here is an example of a Billings method chart. The babies represent possibly fertile days.

Conclusion:

I hope this post helps you think critically about whether calendar-based methods for opening the fertile window are right for you!

Here is a breakdown of efficacy for these methods:

Daysy: Claims 99.4% perfect use, but their study was retracted.

Natural Cycles: 98% perfect use, 93% typical use.

DOT app: 99% perfect use, 95% typical use.

Billings Method: 97.8 to 100% perfect use, typical use varies depending on country.

**Some modern fertility awareness methods use the Doering Rule to set the opening of the fertile window. This can be very safe and yield high efficacy. Doering is based on the earliest temperature shift of all time (not just the last year).

An Honest Review of Proov PdG Tests

Are you interested in testing your PdG at home with Proov?

Proov tests check levels of the hormone metabolite PdG in the urine. Proov tests are an FDA approved product. People who are ovulating produce the hormone progesterone after ovulation. If you are a fertility awareness charter, you can use these tests to double check that ovulation has occurred along with your other fertility signs. If you are seeking to become pregnant, you can use these tests to help see if your luteal phase is sufficient to support a pregnancy.

Here are a few links on recent studies so that you can be more informed about using this product:

Proov is Clinically Validated

Study on Urinary Hormones and Progesterone

Study on Proov Combined with Fertility Awareness Methods

Study on Combining Proov with Clearblue

I have personally been using Proov for over a year and a half now. It is a regular part of my fertility awareness routine that I use to avoid pregnancy.

This is my Read Your Body chart. The yellow plus signs are for LH (luteinizing hormone) positives. The blue plus sign is for Proov test positives. On this chart, I got a positive LH (luteinizing hormone test) on Day 18 and a positive Proov test on Day 21.

My most common day to get my first positive Proov is approximately 3 to 5 days after a positive LH test. I love having Proov as a crosscheck so that I can have an extra way to confirm ovulation. I like having a ton of data in my fertility awareness routine. While there is currently no official protocol for confirming with Proov tests (outside of Marquette method tentative guidelines), you can use them as a part of your fertility awareness routine regardless of your intentions. You should still rely on the fertility signs in your method rules while using Proov.

For those trying to conceive, the tests can be used around 7 to 10 days post ovulation (counting from peak day, temperature shift, or positive LH depending on what you are charting). If the tests are positive, this is a good sign that your progesterone is high enough when implantation is most likely.

I used it 7 to 10 days past my first positive ovulation test to see if my progesterone levels were high enough in the last part of my cycle. Ideally, for conception purposes, you want to see positive Proov tests on days 7 through 10.

These tests are also useful for people with irregular cycles or tough cervical mucus patterns because they can help you know if you have indeed ovulated.

Proov also has an app that can help you read your tests, including LH tests. It recently updated to include numeric values. This makes the data even more meaningful! Some people struggle reading Proov, and the app is definitely useful for those people.

I highly recommend trying Proov if you are curious about your progesterone! For now, I have decided to make Proov a permanent part of my avoiding pregnancy fertility awareness routine.

Want to try Proov after reading my review? Please use the promo code chartyourfertility for 30% off!

Thank you!

Cool Femtech that You Can Use (With FAM) to Avoid or Achieve Pregnancy

As you probably know if you have read any of my previous critiques of femtech, I am often wary of it. However, there are some devices and tools that I can 100% get behind because they allow user interpretation or are a part of a fertility awareness based method. The following list is of devices that can be used with a fertility awareness based method to avoid or achieve pregnancy.

The Mira Fertility Monitor is a new device that measures your hormonal levels to help you get pregnant. As far as I know, the Marquette method is working on including the monitor as an option to avoid pregnancy in the near future.

Order Mira now through this link to receive $20 off your order!

The Tempdrop Thermometer is a wearable BBT that you can use to get accurate temperatures no matter your amount of wake times during the night. This is super useful for postpartum women or those who have irregular sleep times!

Click here to read my Tempdrop Review and use my referral link to get $15 the two top tier options.

Proov Test Strips are used to determine if your progesterone levels are high enough to sustain pregnancy and as an extra way to confirm ovulation for those avoiding pregnancy. I have personally used these as an extra layer of ovulation confirmation.

Order them at this website: Proov Test. You should see an option to get 10% off your first order.

An Honest Review of Pearl Fertility Kit

I tried the Pearl Fertility Kit. During my first kit, I got a little confused when the kit did not seem to line up with my fertility signs. However, I contacted Pearl Fertility and they were super helpful. They sent me another kit for free, and it worked perfectly when I tried it this last cycle.

Pearl is a product marketing to women who are trying to conceive (TTC). The product explicitly states that it should not be used to avoid pregnancy. The kit contained 15 follicle stimulating hormone (FSH) strips, 15 luteinizing hormone (LH) strips, and 4 progesterone (PdG) strips. It also included a few pink dye pregnancy tests. As I am not currently trying to conceive, I did not use these.

The app claims to open a woman’s fertile window by scanning the FSH and LH strips and giving you a fertility window from these results.

If anyone wants to try this product, I highly suggest tracking your cervical mucus, as good quality cervical mucus (eggwhite, clear, stretchy, wet) is what allows sperm to survive to meet an egg. Progesterone tests need not be used until at least 4 days past your peak day (the last day of good quality cervical mucus). Even then, some women do not see positive progesterone tests until as late as 7-10 days past ovulation. For more information, visit Proov’s website linked at the end of this article. By charting your real fertility signs, you could use these tests more wisely.

Overall, I thought the Pearl Fertility Kit was super cool. FSH strips are a brand new thing, and I have high hopes for them being integrated into a real fertility awareness based method in the future. If you have the money to invest in Pearl, this can be a fun kit to experiment with. Basically you get to see three main hormones of the menstrual cycle play out. Pearl graphs them for you.

If you cannot afford Pearl, do remember that it is free to chart cervical mucus and that this is always the best indicator for when to have sex when trying to achieve pregnancy. Without cervical mucus, sperm will never make it to the egg on its own.

Here is what my Pearl chart for this month looks like:

The highest pink dot is my positive LH strip.

Here is my Pearl information compared to my symptothermal method chart. In this chart, FSH equals Ferning since Kindara does not have an FSH category.

The Pearl fertile window is indicated by the green lights. It did start my fertile window on a day pregnancy was unlikely since there was no mucus. The blue hearts represent the fertile mucus where sperm can survive. These two fertile windows lined up pretty well.

Overall, I would rate myself satisfied with this kit.

One tip:

From the calendar screen, you can override what tests Pearl is asking for. I only suggest doing this if you are charting your other fertility signs (cervical mucus and basal body temperature) and know that something is not lining up right.

In addition to the strips, Pearl has spaces to track intercourse, your period, and pregnancy status.

Curious to know more about the fertility signs?

If you want to learn how to chart your real fertility signs to achieve or avoid pregnancy, read my guide to getting started.

Look for my next blog on using Proov progesterone tests.

An Honest Review of Tempdrop

Are you looking to simplify your basal body temperature charting routine? Is getting up in the morning just too hard to remember to take your temperature? Read on!

There are currently a few wearable basal body thermometers on the market such as iFertracker, Ava, and Tempdrop. In this blog, I will review the Tempdrop device. If you decide to purchase, use this link and get $10 USD off the device.

Tempdrop is a wearable basal body temperature thermometer that came onto the market in 2017. Rather than setting an alarm, you can simply put this thermometer on before bed. You wear it around your upper arm (and it may be worn in a bra as well). It needs 3 hours of sleep to determine your basal body temperature. The device uses an algorithm to find your true temperature, regardless of how many times you have gotten up or whether you had restless sleep this night.

This device is very popular with shift workers, breastfeeding folks, and other people who don’t get a regular amount of sleep and wake up at different times, or just to those who don’t want to set an alarm!

Tempdrop holds 24 hours of data, and it must be synced at least every 24 hours or you will lose previous data. After wearing it for 15 days (as of March 2020), the algorithm will kick in. (If possible you should back up temp with oral basal body temperature for the first 60 days if you are avoiding pregnancy. If not, use a different method of protection). By day 60, the device will only change and make improvements to the last 2 temperatures taken.

Once you wear it, you will need to sync it to an app to see your temperature. Tempdrop has its own app, but I highly recommend using Read Your Body (pictured below) instead! This app is customizable for every method and can be synced to Tempdrop.

My Experience with Tempdrop

Tempdrop is red and oral temperatures are blue! One perk of oral temperatures is that sometimes I can skip taking my temperature, while with Tempdrop you do wear it daily for best results.

I used the Tempdrop device for almost 12 months. I found my oral temps to be more predictable and more steady when observing my own trends over time. I get very steady or repeating temperatures with oral charts most of the time.

However, I am not a shift worker, so I will admit that I do not need Tempdrop like some people may do. I already have to wake up at the same time 5 days a week, and I don’t find it inconvenient to take my temperature on the weekend. My oral temperatures caught my shift earlier than Tempdrop did on two separate occasions. I have seen other people say that Tempdrop catches their shift sooner than oral temperatures, so this is really an individual thing.

For full disclosure, I ultimately stopped using my Tempdrop in favor of using a sympto-hormonal form of charting that doesn’t require temperatures.

I discovered that there were multiple other effective ways of charting without taking my temperature. If you really want to chart in shift work, irregular cycles, postpartum and you do not want to purchase the Tempdrop, I highly recommend considering learning a new method of fertility awareness like the Billings Ovulation Method (click here to learn about working with me) and Marquette method (click here to learn what charting with Marquette is like).

If you are dedicated to using a sympto-thermal method and can’t get accurate temperatures otherwise, and you have tried trouble shooting your routine (vaginal temperatures, pre-warming the thermometer before taking it, using longest stretch of sleep), then Tempdrop may be your best option. You can use my code for $10 USD off, and I will get a small kickback. Thank you for using my code!

Here is what the device looks like!

 

Why I Do Not Suggest Using Natural Cycles

Natural Cycles costs around $10 a month, or $80 a year. The app claims to be able to tell you when you are and when you aren’t fertile by using basal body temperature (ovulation strips are optional).

This claim is not true. Natural Cycles only has a 93% typical use efficacy rating. After my experience, it seems even lower than that. I used Natural Cycles for 3 cycles and compared it with the sympto-thermal (STM) method that I use. The method I use is 98.2% effective with typical use.

As a long term charter, I use a doering rule (a rule to limit dry days). My last safe day for unprotected sex is day 5 of my cycle (usually the last day of my period) because of this rule. This rule is included in the high efficacy rates of the sympto-thermal method.

The charts that follow show when my method said I was safe versus when Natural cycles told me I was.

I have compiled 3 of my charts for comparison. During more than one cycle, Natural Cycles told me I could have unprotected sex on the day near my PEAK fertility. Peak day is the most likely day of ovulation, while not always the exact day of ovulation. Suffice it to say, the app told me that I could have unprotected sex on a day when pregnancy was still possible.

September Cycle (First with Natural Cycles)

On my very first cycle, without any knowledge of whether I had ovulated the cycle before, Natural Cycles gave me clearance to have unprotected sex during my period.

This is totally wrong. Without having confirmed ovulation the previous cycle, there is no way to know if this bleeding is safe or not.

The next BIG issue is that it told me I could have unprotected sex on the second day of my temperature shift (CD17). There is a huge chance that my egg could have still been viable and hanging at this point.

With the symptothermal method, you CANNOT confirm ovulation before 3 high temperatures.

The chart below has my actual safe days as calculated by doering. (Keeping in mind that I did confirm ovulation the cycle before so my period is safe. However, there is no way that Natural Cycles could have known that).

september 1

October Cycle (Second with Natural Cycles)

late september nc cycle

For the second time, Natural Cycles gives me a green light on the second day of a temperature shift in the morning. My egg could still be around! In fact, this green light was less than 24 hours after my peak day!

october 1 cycle

November Cycle (Third with Natural Cycles)

late october nc cycle

During this cycle, Natural Cycles decides that I’m not safe on CD 5 (I am).

It also gives me a green light on CD20. However, I would not be safe to have unprotected sex until the evening of CD21 due to peak day occurring on the first day of my shift.

oct 27 cycle

Conclusion

Natural Cycles does not follow the rules for STM charting.

When charting with STM, one must always wait until the evening of P + 3 and T +3 (three high temperatures and three days after peak). Both rules have to be met before you can have any unprotected sex. With weaker shifts, this wait can be a day longer.

Natural Cycles does not include cervical mucus. Since cervical mucus is what opens the fertile window (and not temperatures), this causes the method to lose efficacy. Cervical mucus is what allows sperm to survive and fertilize an egg. When cervical mucus dries up for 3 days and 3 high temperatures above the coverline occur, ovulation is confirmed for the cycle. Any app that leaves out cervical mucus, but still lets women have green days pre-ovulation, is misleading women and putting them at extra risk of pregnancy.

Another worrisome aspect of the app is that it frequently gave me a green light on the morning of the second high temperature. Temperatures can easily be disrupted, and new charters may not know their normal temperature ranges. Women need to be certain that ovulation is over before having unprotected sex. The third high temp (along with the third day after peak day) lets you know that ovulation is confirmed. Green lights after only one or two temps can put women at a risk of pregnancy, especially when cervical mucus isn’t taken into consideration. In fact, most STM methods require 4 high temps for women who don’t use cervical mucus (or cervical position). The reason that Natural Cycles may interpret shifts wrong is because of its static coverline. Some women may not see much of a change in coverlines from cycle to cycle. However, others may see a change. Having a static coverline can give users green days before they actually have a temperature shift.

Lastly, the app is misleading because it marks the day of ovulation. The only way to truly determine the exact day of ovulation is with a well-timed ultrasound. In fact, ovulation is most likely to occur over a period of about 4 days. Here is the link to the study that discusses which 4 days are the most likely. Since ovulation is likely up to day 2 of a temperature shift, this proves even further why it is so risky for Natural Cycles to give green lights on day 2 of a shift. In the other 9% of cases not hightlighted in the green box below, ovulation happened up to 3 or 4 days before a shift. This is why mucus is so important to record pre-confirmed ovulation. If there is mucus present, the sperm may live. Natural Cycles does not take enough factors into account when drawing its fertile window.

ovulation


If you are coming off of hormonal birth control or postpartum, this app may be an even worse choice for you. Those coming off hormonal birth control and postpartum may experience cycles changing in length and unexpected early ovulation even more so than people with regular cycles.

Anecdotally, I have seen many risky charts from Natural Cycles in the group I help moderate. You can find a link to this group here.

I highly recommend learning a real sympto-thermal method from an instructor and not wasting your money on the Natural Cycles app. I found it quite shocking that is was not very conservative when first learning about my cycles.

Check out my last post to learn how to start charting on a budget. Click here to sign up to learn to chart with me when my course opens in September 2019.

Here are some other articles on Natural Cycles that I recommend reading:

Natural Cycles’ FDA Approval: What’s The Big Deal?

5 Reasons I Don’t Use Daysy Or Natural Cycles

‘I felt colossally naive’: The Backlash Against the Birth Control App