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Natural Cycles vs Daysy vs Ava: Which Fertility Tracking App Is The Best?

For a long time, fertility has been an expensive, taboo topic to dive into. More recently though, women are opening up space to talk about their fertility journeys, especially in the wake of overturning Roe vs Wade. 


Companies like Ava, Daysy, and Natural Cycle are introducing new ways to track fertility. Moving away from birth control pills, these digital fertility trackers offer an all-natural hormone-free birth control by helping you to get clued in on your fertility window and ovulation days.


Not everyone is interested in fertility tracking for the same reason. 60% of women are looking to fertility tracking methods to prevent pregnancy, others are hoping to use these tracking methods to help them get pregnant, and some just simply want to understand their menstrual cycles on a deeper level. 


Instead of shelling out thousands of dollars and tons of time with doctors’ appointments, these women’s fertility tracking health startups have found ways to make fertility tracking something that can be done at a much lower cost, accurately, more naturally, and on your own time. Because let’s be honest, these days, we’re all about that instant gratification. 


Curious about fertility tracking accuracy or worried about your personal data being weaponized against you in the wake of overturning Roe v Wade? Let’s dig a bit deeper into these three fertility tracking apps – Natural Cycles vs Daysy vs Ava – to see which is the best fit for all of your fertility needs. 


TLDR: Which fertility tracking app do we recommend?


Short on time? Here are our top recommendations:


Choose Natural Cycles if you want a budget-friendly option with all the features of other competing apps. They are also one of the leading apps working on a “completely anonymous experience”.

One downside: you have to manually record your daily basal body temperature (BBT) into the app.
Choose Daysy if you want an almost entirely error-free app. Daysy determines your fertility with a remarkable 99.4% accuracy. And, it automatically syncs with your smartphone app to give fertility statistics and reports.Not thrilled by the idea of measuring your BBT right when you wake up before you can even go to the bathroom? We recommend Ava, a bracelet that you wear during your sleep, allowing it to collect data overnight.

Ava is only for those looking to get pregnant and track their pregnancy progress. Ava is not for someone looking for a contraceptive device.

But don’t just take our word for it! Read on to get into the nitty-gritty of Natural Cycles, Daysy, and Ava. 


How effective is fertility tracking?  


In the wave of saving money and rapid results, self-tracking fertility apps are on the rise. Maybe you’ve hit a roadblock in your pregnancy journey and are struggling to conceive, or maybe you know it’s just not yet your time to have a child, but don’t want to use hormonal birth control. Whatever your motives are, there is a fertility tracking option for you. 


So, what is fertility tracking? Simply put, it is knowing when your fertile window is, and even more specifically, when you’re ovulating and could get pregnant. Fertility tracking apps help women predict when that fertile window is, and a recent study found that “the efficacy of a contraceptive mobile application is higher than usually reported for traditional fertility awareness-based methods and suggested that the application may contribute to reducing the unmet contraceptive planning needs for women”.


Fertility tracking apps (FTA) utilize three different accurate methods


  1. Daily oral basal body temperature to identify ovulation
  2. Cervical fluid consistency
  3. Urinary LH levels

The science behind fertility tracking apps is evolving and is not meant to be in place of a regular doctor visit, but instead allow for at-home, enhanced knowledge of your cycle and fertility. 


It seems rather empowering as a female to know when you can and can’t get pregnant, doesn’t it? Whether that information is used to avoid contraception or to help a woman get pregnant after many attempts lacking fertility knowledge, simply knowing more about your own cycle and body is a great tool.


Other benefits of hormone-free fertility tracking include: 


  • Enhanced knowledge of your cycle
  • A natural way to track your cycle
  • Side-effect free
  • Low-cost
  • Real-time knowledge, at home


Which Fertility Tracking App is best: Natural Cycles, Daysy, or Ava? 


When you’re tracking your fertility, you want to make sure the app you’re using is giving you exactly what you and your partner want. The good news is that there are several different FTA options to choose from, including Natural Cycles, Daysy, and Ava. Beyond the cost and process, there are different features and utilities for each that offer women the ability to select options ranging from a bracelet to a thermometer to track fertility. Let’s dive in and compare the options to see which fertility tracking method is best for you! 


Best fertility tracking apps: Natural Cycles vs Daysy vs Ava

PriceAnnual: $89.99
Monthly: $9.99


$279 to $359
Device/HardwareThermometerThermometerFertility Bracelet
Efficacy98% with perfect use
93% with typical use
Cycle tracking and ability to identify fertile window
Tracking device stores your data
Tracking device automatically syncs to the app?
Fertility cycle report/statistics
PMS, pain and other menstrual cycle tracking
Effective for irregular cycles
IOS/ Android compatible app
FSA/HSA Eligible
Pregnancy tracking
FDA Cleared
Geographic AvailabilityShips to countries all around the world EXCEPT: Mexico, Argentina, Columbia, South Africa, Saudi Arabia, the United Arab Emirates, and ChileUS, Europe, and CanadaUS


Each fertility tracking method has an app that correlates with the procedure to store data and allows you to look back on your cycles, making all of your data extremely easily accessible, right at your fingertips. Now let’s explore each tracker in a bit more detail. 


Review of Natural Cycles hormone-free birth control 


Source: Natural Cycles


Natural Cycles was the first FDA-approved app for determining a woman’s fertility window to help in birth control and pregnancy planning and are one of the leading apps working on a “completely anonymous experience”. Natural Cycle’s co-founder and co-chief executive, Raoul Scherwitzl, told Wall Street Journal that “the goal is to make it so no one—not even us at Natural Cycles—can identify the user”.



The idea for Natural Cycles was conceived when founders Elina and Raoul decided they were in need of an effective method of natural birth control. The two set out on a journey of analyzing Elina’s own temperature and devising an intuitive algorithm for fertile days. 


The two founders used Natural Cycles, successfully, for its dual uses: both as a preventative and a planner. Ever since its inception, Natural Cycles has been carrying out its mission to pioneer women’s health and empower women with the knowledge of their own personal health. 


How does Natural Cycles work? 


Source: Natural Cycles


Natural Cycles can be purchased on either a monthly or annual subscription basis. A basal thermometer comes for free with the annual subscription, but must be purchased separately with the monthly subscription (available at most pharmacies). 


Natural Cycles uses an algorithm based on a woman’s basal body temperature to determine fertility status. It’s a rather simple process, really. All you have to do is measure your temperature, input in the app, and allow the algorithm to calculate your fertility, and voila: fertility and cycle knowledge in the palm of your hands. 


Measuring basal body temperature (BBT) is used to help detect ovulation. The algorithm created by the two founders is regulated, certified, and “learns the pattern of your unique cycle to work out daily fertility status”. You don’t have to measure BBT every day, but getting into a routine will help to allow the app and algorithm to understand your cycle better. 


Furthermore, information about your menstrual cycle length (taking fluctuations and irregularities into consideration) can help forecast your fertility. Finally, although not required, the results of your optional luteinizing hormone (LH) test (LH levels spike immediately before you ovulate) can also help determine your fertility. An LH test is performed using a urine test strip, which may be purchased at your local drugstore or through the Natural Cycles app


The Natural Cycles app gives you a clear daily status of green (not fertile) or red (use protection), so it’s crystal clear as to how you need to proceed during intercourse (depending on what you want, that is). 


This color scheme is clearly for those trying to prevent pregnancy. If you’re trying to conceive, the rules of the road are a bit backward – red means go, green means no (no conception, that is. Nothing to do with how you spend your time, though…). 


Source: Natural Cycles


Is Natural Cycles FDA approved?


Yes! Natural Cycles was approved by the FDA as the first app-based birth control in 2018.  


Is Natural Cycles covered by insurance?


Natural Cycles is not currently covered by insurance but can be purchased with FSA or HSA. 


Getting started with Natural Cycles


To get started, you must download (and purchase) the app. Natural Cycles offer various plans, making it truly a long-term fertility partner:


  • NC Birth Control (preventing pregnancy)
  • NC Plan Pregnancy (finding fertile days)
  • NC Follow Pregnancy (monitoring pregnancy)

Temperature readings must be taken first thing in the morning when you’re still in bed before you can even use the bathroom. To use the app, you’ll need a basal thermometer (which can be purchased separately or in combination). Basal thermometers are more sensitive than regular fever thermometers, as they show two decimals (which is significant, by the way!). It’s recommended to forgo taking your temperature on days when you are feeling sick and assume your temperature has risen due to illness.


You’ll enter your current temperature into the app, where you can also add data about your cycle to track symptoms and learn more about your unique menstrual cycle. There’s space for you to document any PMS, pain, sex drive, or mood changes. You can use those symptoms and a graph feature to see patterns. 


Source: Natural Cycles


How much does Natural Cycles cost?


There are two subscription plans available for Natural Cycles app:


  • Annual: $89.99 (includes the thermometer)
  • Monthly: $9.99 (thermometer at an additional cost)


If you want to test Natural Cycles before paying for the service, you may try it out in a free demo mode by installing the app.


How accurate is Natural Cycles?


Natural Cycles claims to be 98% effective with perfect use and 93% effective with normal use. What’s the difference between normal and perfect? Great question – perfect means not having unprotected sex on any of the red days, normal means maybe accidentally slipping up once or twice. Because Natural Cycles if FDA approved, they are required to monitor this effectiveness rate on a regular basis, so we know this is legit.


Compared to birth control methods like hormonal birth control pills or IUDs, it is less effective, but it’s more effective than methods such as condoms or withdrawal with no other form of contraception. The allure of Natural Cycles is the non-hormonal characteristics – if this is your goal, Natural Cycles is a great way to better know your body and help to prevent (or aid!) pregnancy.


Natural Cycles Reviews: What do customers think of Natural Cycles fertility tracking app?


Source: Trust pilot 


Source: Google Play 


Many of those coming to Natural Cycles have been referred by a doctor, are in the midst of their own search for hormone-free birth control and cycle tracking, or are tired of their current system of trying to track their fertility on their own. Those who’ve transitioned to Natural Cycles were happy with the results they’d received thus far and with how much they’d learned about their body!


Always keeping in mind that all of our bodies are different, Natural Cycles has positive reviews overall. We do want to note that it’s very important to read the fine print, especially for the app. There are reviews that discuss being charged for a renewal that they didn’t expect – so always be aware!


Daysy fertility tracker review


Source: Daysy 


Backed by Valley Electronics, an international research-based medical technology company, Daysy’s mission and vision is all about women connecting with their own “body intelligence” and striving for empowered living through fertility tracking. The Daysy team is passionate about supplying women with non-invasive fertility technology that enables women to translate “the body’s existing data, and makes fertility tracking the new, effortless normal”. 


Similar to Natural Cycles, Daysy uses BBT and menstruation data to help women understand their most fertile days. Daysy’s technology combines: 


  • A precise temperature sensor
  • A unique, intelligent algorithm based on a database of 5 million menstrual cycles
  • An intuitively designed tracker 


How to use Daysy


Daysy makes the process effortless, so all the user has to do is regularly take their BBT when they wake up and input their menstruation cycle days. Beyond that, the algorithm and app do the rest. Daysy’s unique, precise thermometer takes your temperature and stores your data immediately, and then calculates your fertility status. 


You don’t have to worry about forgetting what your BBT was before transferring your data, Daysy does it all for you. Easy, and quick. Daysy’s thermometer, unlike Natural Cycles, connects through Bluetooth to the app on your smartphone.


If you forget what it recorded one morning, you can always turn it on and it will remind you, or you can sync with the app to check later in the day.


After the learning phases in which Daysy gets to know your body, the algorithm begins to forecast your ovulation and begins your fertile window five days before your ovulation date. The fertility algorithm is based on 30 years of research and 5 million menstrual cycles, so you can rely on Daysy’s calculations. 


Source: Daysy


If you’re trying to get pregnant, pay attention to the road signs, because the color indications from Daysy are a bit backward (similar to Natural Cycles):


  • Red light – fertile or possibly fertile
  • Red flashing light – your predicted day of ovulation
  • Green light – not fertile
  • Yellow light – cycle fluctuations (Daysy is in its learning phase)
  • Red, green, yellow – possible pregnancy


Now, if you’re not intending on having a baby and you’re using Daysy for a contraceptive method, the lights are spot on. Green means go ahead, do your thing. Red means mmmm better not, and flashing red means absolutely not. 


Daysy understands that timing is crucial when planning to conceive. The window is small, but Daysy allows you to have a better understanding of your most fertile days, and even a predicted ovulation day, so you better plan your pregnancy with your partner


Source: Daisy 


How much does the Daysy fertility tracker cost?


Daysy fertility tracker costs $299, which includes the DaysyDay app. There are additional online educational courses and accessories available for purchase in combination, as well.


Is Daysy covered by insurance?


In addition to the ability to purchase Daysy with FSA or HSA, most insurance companies cover or reimburse up to 60% of Daysy. It’s a great idea to talk with your insurance company before making any purchases.


Is Daysy FDA approved?


Valley Electronics AG is registered with the FDA, confirming that Daysy is FDA approved. In addition, Daysy is audited yearly by an independent European Notified Body for quality management.


How reliable is Daysy?


Daysy is reported to have an overall accuracy of 99.4% in correctly identifying infertile days vs fertile days. According to Daysy, 81% of couples who are tracking their fertility and timing intercourse on their fertile days will conceive within 6 months, and 92% will conceive within 12! 


By using the Daysy thermometer alongside the DaysyDay app, you can have the knowledge to make your dreams of having a child come true. And, even better there are no doctor visits, pee strips, intricate algorithms, or guessing, so you can focus more on the baby-making, and less on the calculations.


Just like Natural Cycles, you should skip measurements when you are feeling ill or when you’re taking medication that could influence your cycle or body temperature


Daysy reviews: What do customers think of the fertility tracker?


Source: Trust pilot

Source: Google Play 


Overall, the results are positive towards Daysy’s ability to track fertility. Because, again, everybody’s bodies are different, Daysy’s accuracy relies heavily on your own ability to use the device correctly. The number one advantage to Daysy is fertility awareness and getting to know your body more, which most report only needing ~3 months to feel more knowledgable and in-tune.


Review of Ava fertility bracelet


Source: Ava


Since 2014, Ava has been striving to provide data-driven insights to help women with infertility. The company has published more than 30 peer-reviewed clinical papers, become the first wearable fertility tracker with FDA clearance, and in 2020 celebrated the 50,000 pregnancy mark from users. Ava has done research to compare the difference between the BBT method and wrist skin temperature and found that wrist skin temperature was more sensitive (you can check that article out here). 


If you would like to know more about Ava, we have covered it in-depth in our article best ovulation trackers and compared it to its most popular contenders that use similar technology. 


How does the Ava bracelet work?


Source: Ava


Ava is a wearable fertility tracker that overnight, collects continuous data while you sleep so you don’t have to lift a finger. The device tracks signs of  following hormonal changes:


  • Skin temperature
  • Resting pulse rate
  • Blood circulation through tissues/perfusion
  • Breathing rate
  • Heart rate variability


In the morning, all you have to do is sync up your bracelet to the app to see results. The tracker and its accompanying app are designed to assist couples attempting to conceive in determining their 5-day fertile window, during which sex is most likely to result in pregnancy. This tracker is exclusively intended to help couples to become pregnant. According to Ava, it is not to be used as a contraceptive device, which means it is not approved to prevent pregnancy.


The technology Ava uses gives real-time results, without having to worry about remembering to take your temperature every morning. According to Ava, by using physiological signals that act as markers for your fluctuating hormone levels, Ava can detect which phase of the menstrual cycle you’re in. It accomplishes this by analyzing the 3.5-million cycles of data acquired from its users over time and employing machine-learning algorithms to offer the most accurate findings for the widest range of women’s cycles.


Source: Ava


Ava app goes the extra mile and also displays sleep, physiological stress, resting pulse rate, and temperature, all so you can have the knowledge of when you’re in the best physical state for baby-making. They also provide cycle reports, with an overview of length, luteal and follicular phase length, ovulation, and menstrual flow so you can have the information yourself, or can access all of your prime information to share with a doctor. 


What Ava is really looking to do is aid women in their pregnancy journey. The app and bracelet allow you to track your pregnancy progress with analysis of trends and content throughout the entirety of your pregnancy. Ava also states that nearly 30% of sub-fertile women report pregnancy within one year of using Ava Fertility. 


Source: Ava


How to wear the Ava bracelet


  1. Charge bracelet for at least 4 hours before first use (until LED light is solid green)
  2. Download Ava Fertility app (App Store or Google Play)
  3. Create account
  4. Answer questions fully to optimize your experience and accuracy
  5. Follow tutorial upon downloading the app to pair bracelet
  6. Before bed, attach the Ava bracelet to your non-dominant wrist
    1. Avoid excessive lotion on wrist
    2. White sensor should sit behind wrist bone
    3. Ensure it’s flush to skin
    4. Tighten band enough that it doesn’t slide
    5. Be sure to attach to the same wrist every night for consistency!
  7. In the morning, tap “sync my data” button on the app’s home screen to confirm your fertility indication (low, high, or peak fertility)


How accurate is Ava Fertility tracking?


Ava Fertility conducted a year-long clinical study in which fertile days were correctly identified by the bracelet and app 89% of the time. Within your cycle, there are six days in which it’s possible to conceive. Ava Fertility detects five of them, so you’ll always know the best time to try to conceive. 


How much does the Ava fertility bracelet cost?


Ava offer three packages, all of which include access to both the app and the fertility bracelet:


PackageCostWhat’s included
Ava Fertility Basic$279Ava Fertility Bracelet

In-app cycle, fertility, and pregnancy tracking

Ava’s online community membership
Ava Fertility Plus$309Ava Fertility Bracelet

In-app cycle, fertility, and pregnancy tracking

Ava’s online community membership

A full refund (if not pregnant within 12 months)

E-book: Ultimate Guide to Getting Pregnant
Ava Fertility Premium$359Ava Fertility Bracelet

In-app cycle, fertility, and pregnancy tracking

Ava’s online community membership

A full refund (if not pregnant within 12 months)

E-book: Ultimate Guide to Getting Pregnant


Ava fertility bracelet reviews: What do customers think?


Source: Trust pilot 

Source: Google Play 


Many users of the Ava fertility bracelet rave about how easy the device is to use and how much more convenient it is compared to other fertility trackers. Rather than manually running “tests” every morning, the bracelet does all the work for you. There are some that have mentioned difficulty in syncing data, but troubleshooting can be made easy with their customer service department, which was also praised. 


The verdict: Which fertility tracking app is best for you– Ava vs Natural Cycles vs Daysy?


One of the biggest deciding factors for which fertility tracking method is best for you: do you want a baby, or are you trying to prevent one? 


Each brand has its own unique features to differentiate it, but really what you need to evaluate is where you’re at in your fertility journey. If you’ve had any struggles with fertility and conceiving, the Ava Bracelet might be for you, compared to Daysy and Natural Cycles. Ava is also the only wearable tracker, so if you prefer that to the daily BBT method and thermometer, it also might be for you. 


Daysy has the unique ability to automatically input your information from the thermometer to the DaysyDay app for a seamless transition to give insight into your fertility. Natural Cycles is in a similar boat, using the BBT method for fertility tracking, but it does not have the ability to automatically sync to the app. 


Each fertility tracking method comes with an app that allows for reports on previous menstrual cycles and fertility data, and each has a device to use alongside. The demographic of the Ava customers is solely those looking to get pregnant, whether they have had struggles conceiving prior, or not, while the demographic of the Natural Cycles customers skews more towards those looking for natural, non-hormonal birth control. 


Daysy has a more split demographic, with some utilizing the BBT readings to help with conception, and others using it as a form of birth control or deeper understanding into their personal fertility knowledge. 


FTAs can all empower their users in a different way and are non-hormonal options for fertility tracking. The question of which is best, Natural Cycles, Daysy or Ava, really can only be answered by you and the stage of life you’re in. Are you looking for contraception, or conception? The choice is yours! 


Additionally, if you are interested in finding more about this concentric area, we have reviewed  fertility kits for men, other birth control options, and prenatal vitamins, check out each link or head to our website, FinvsFin!  


Comment below if you’ve had any experience with any of these fertility tracking apps (or any others). We would love to hear about your experiences! 

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