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If you’ve been hanging around these parts for any length of time, you probably know that I am a bit of a women’s health tech junkie.

So much so, that my cohost on The Period Party podcast, Nat Kringoudis often teases me on air because I use not one, not two, but three devices to track my period and fertility signs. Yup, I’m a self-confessed hoarder of fertility and period tracking devices and apps.

What can I say? It’s a reallllly cool time to be a woman right now. The women’s health landscape is changing rapidly right before our eyes, and I want it ALL.

My love affair with all things period tracking

In case you’re curious, I started this whole period tracking adventure many years ago, long before iPhones and apps. Lordy, I’m dating myself. When the iPhone came on the scene, I started using iPeriod because it was literally the only app I could find at the time with a chart that would display my basal temperatures.

Then along came Kindara in 2011. I read about them in the NY Times and immediately downloaded their app. I’ve been a loyal user ever since. When they debuted their Wink thermometer I got me one of those too!

In 2016 I got my hands on a Daysy Fertility Monitor and immediately fell in love with the ease of use. I was especially excited for my post-hormonal birth control ladies who couldn’t totally wrap their heads around charting their cycles and the Fertility Awareness Methods. Many of them needed a segue to natural birth control, and the Daysy was it.

And now, my latest addition to the pack is the Ava Fertility Bracelet, which I have christened as the fitbit for your menstrual cycle and fertility. It measures parameters such as body temperature, breathing rate, and heart rate variability amongst others, which all change depending on which menstrual cycle phase you’re in (follicular or luteal).

Before I go any further, I want to preface this post by saying the Ava is not a device that should be used to prevent pregnancy. It’s not yet designed or approved for that purpose. More on that in a moment.

So, who is the Ava Fertility Bracelet for?

The Ava website states three ways in which the Ava bracelet can be used – to track your cycle, track your fertility and track your pregnancy. More specifically, it’s for…

Please note: The Ava is suitable for women with cycle lengths between 24-35 days. They say on their site future versions will support more irregular cycles.

This is what the Ava Fertility Bracelet does…

  • Ava is clinically proven to detect the very beginning of the fertile window in real time.
  • Ava was shown to detect an average of 5.3 fertile days per cycle at 89% accuracy in a scientific study.
  • For women who are trying to get pregnant, Ava doubles the chances of conceiving each month.
  • Ava gives you insight on your cycle phases, stress, sleep patterns and other aspects of your health.

How does the Ava Fertility Bracelet work?

The Ava bracelet is worn like a watch, at night while you are sleeping. So, you’ll want to get a wall plug that has a USB port on the other side, plug the Ava cable into the USB port and then charge your Ava.

Before bed, unplug the Ava put it on either wrist and then take it off when you wake up. Plug it into the wall charger, turn on the bluetooth on your phone and sync it so you can see the data from the night before on your app.  You’ll want to leave it to charge throughout the day because the battery dies after about 48 hours without charging it.

The Ava must be worn for 4 hours to work properly, and you need at least 3 hours of sleep for it to get an accurate reading to calculate your fertility.

While you’re wearing the Ava it measures specific physiological parameters when your body is completely at rest. These include:

  • Skin temperature
  • Resting pulse rate
  • Breathing rate
  • Heart rate variability ratio (HRV)
  • Sleep
  • Perfusion
  • Movement
  • Bioimpedance
  • Heat loss

Keep in mind you’ll only see the first FIVE parameters in the app. The remaining ones are used in combination to determine the results for the first five parameters with greater accuracy.

Measuring all of these physiological parameters (which are markers for your hormone levels) enables Ava to sense which phase of your menstrual cycle you’re in.

Further, Ava’s algorithm distinguishes between an actual signal and just random responses to external stimuli like stress or too many donuts. 😂 For instance, it helps to recognize whether an increase in pulse rate is due to impending ovulation or simply stress.

If you’re already excited about the Ava you can get your hands on one right here. I’ve got a $20 discount just for you with code: hcajardim at checkout. 

My experience with the Ava Fertility Bracelet

I’m feeling this device for a number of reasons…

#1 It tells me how much sleep I got, and how much of that sleep was light or REM sleep. I really like this because it’s pushing me to go to bed earlier and make sure my sleeping environment is on point! I’m also paying attention to how my sleep is impacted by the different phases of my cycle. I already suspected it was better in the first half of my cycle, but now I know for sure! 😬

#2 The fertility window is unquestionably accurate. Last month it readjusted my fertile window to a day later (May 8th instead of May 7th), based on the data it had been collecting since I began using it on April 15th (which was the middle of my previous cycle). Impressive!

This month I ovulated a few days earlier than normal, and on Day 9 when I synced my data I got another message in the app saying it was readjusting my fertile window starting that day. It was right on because I ended up ovulating on Day 12, 2-3 days earlier than normal for me!

To reiterate what I said earlier – this device is not to be used as a form of birth control. I practice the Fertility Awareness Method using Wink/Kindara and I use the Daysy, so I’m well covered! Your fertile window is longer when using a natural method for birth control.

#3 The HRV ratio definitely lets me know the days I am more stressed out, because it rises as stress rises. A very helpful tool for this business owner who has a hard time slowing her roll. I’m guessing you might be able to relate???

#4 The interface is nice and easy to read and understand. You’ll see resting pulse rate, skin temperature, breathing rate, sleep, HRV ratio and a Daily log (where any notes you’ve entered will show). You can enter notes by pressing the big pink plus sign in the middle of the bottom menu bar.

#5 Ava gives you a cycle report once you’ve completed a full cycle. This cycle report shows details such as cycle length, luteal and follicular phase length, period flow, period length, average day of ovulation and the longest and shortest cycles. You’ll find the Cycle Report option by clicking on the “three dots” on the menu bar. Click on it and have the PDF report emailed to you. Truly, this is the stuff of a period nerd’s dreams. Haha!

#6 I love the idea of using multiple parameters to measure whether ovulation is happening, and when it is happening. Even if you’re not trying to get pregnant, it can give you tons of insight into how your body is responding physiologically to external stressors, lack of sleep, and changing hormones. I have found it to be the perfect complementary tool to my Fertility Awareness Method practice.

If you’re digging the Ava, you can get your hands on one right here. I’ve got a $20 discount just for you with code hcajardim at checkout. 

What my first two months using Ava looked like

Below is my first full month using Ava. As you can see below, I didn’t have a noticeable jump in temperature after ovulation, but I know I ovulated based on my use of Wink/Kindara and Daysy – there was a biphasic temperature pattern on both those apps.

Isn’t it amazing to see the shift in pulse rate and breathing rate from the follicular phase to the luteal phase? The HRV ratio – well that’s based on what’s happening in my life. On the weekend of May 18th-20th, I did a workshop that was very physically and emotionally intense. I thought it was interesting that my HRV was significantly higher on those days.

FYI – I had to capture everything in two screen shots, but you’ll see all of this on one screen on the app.

Below is the second month using Ava. As you can see, there was a more clearly defined temperature shift. The resting pulse rate and breathing rate have a similar elevation. My HRV ratio was super low in the middle of my cycle likely because I was in the Connecticut countryside! Hmmm…maybe I shouldn’t be living in NYC?🤔

Also, my sleep in the first half of my cycle was much longer and better quality than it has been in my luteal phase.

You can purchase an Ava here. I’ve got a $20 discount just for you with code hcajardim at checkout.  

The Science Behind the Ava Bracelet

This convo would not be complete without a review of the science. I mean, who do you think you’re talking to? LOL

From the Ava website:

“Ava was tested in a year-long clinical study at the University Hospital of Zurich. Ava was found to detect an average of 5.3 fertile days per cycle, at 89 percent accuracy (algorithm performance may be improved with more regular cycles, and diminished with less regular cycles).

Results from the clinical study identified multiple physiological parameters that correlate with both the rise in estradiol that precedes ovulation as well as the rise in progesterone that follows ovulation. Ava has protected these methods with multiple patent applications. The first findings from the study were published in May 2017 in the peer-reviewed journal Scientific Reports. A significant increase in pulse rate was observed during the fertile window compared with the menstrual phase (2.1 beats per minute). Moreover, pulse rate during the mid-luteal phase was also significantly elevated compared with the fertile window (1.8 beats per minute).”

Does Ava protect your personal data?

Similar to Daysy, you will find that your data is protected when using the Ava as well. There are some scary stories out there of period tracking apps profiting off of our most intimate details. Helpful reminder – please always read the privacy policy for apps with which you are sharing private data.

Final thoughts

So my goddaughter got her period last weekend for the first time (Goddess help me if she happens to read this!), but I was telling her mom HOW COOL it is that her daughter is going to be able to track her menstrual cycle from her very FIRST period, for the rest of her life! I mean, I know a few women who’d give their right arm for this kind of data on their bodies, me included.

I have yet to meet a woman who isn’t curious about her cycle and what it can tell her about her body. So, how amazing is it that my goddaughter will have that info from the beginning!? I’d totally buy her an Ava, but I think she’s a little young haha.

My point is when you track your cycle and your fertility you become truly “period literate.” If you use the Ava, it’s going to provide a wealth of insight into the goings-on with your cycle. This knowledge will undoubtedly serve you very well in every facet of your life. Ultimately that’s my hope for all women I encounter! ❤

Remember you can get an Ava right here with a $20 discount. Just use code hcajardim at checkout. 

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I want to hear from you!

  1. Was this post helpful for you? Do you use the Ava Fertility Bracelet? If not, do you want to after reading my post? Or, do you have any additional questions about it? Comment below and let me know!
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Medical Disclaimer

Information in this post and on this web site is provided for informational purposes only. The information is a result of practice experience and research by the author. This information is not intended as a substitute for the advice provided by your physician or other healthcare professional or any information contained on or in any product label or packaging. Do not use the information on this web site for diagnosing or treating a health problem or disease, or prescribing medication or other treatment. Information and statements regarding dietary supplements have not been evaluated by the Food and Drug Administration and are not intended to diagnose, treat, cure, or prevent any disease. Always speak with your physician or other healthcare professional before taking any medication or nutritional, herbal or homeopathic supplement, or using any treatment for a health problem.

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