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There are a lot of ups and downs when you’re trying to conceive. If you get that positive on the pregnancy test right away — congratulations! However, many couples benefit from some added help in the baby-making department.

The Ava Fertility Tracker is a device that pinpoints the fertile days in your cycle, taking some of the guesswork out of the process. Here’s more about this tool, how it works, its effectiveness, and other things you may want to consider before trying it out yourself.

The Ava Fertility Tracker is a sensor device — a bracelet — that you wear during your sleep each night. It measures certain physiological features, including:

  • skin temperature
  • pulse rate
  • heart rate variability
  • breathing rate
  • perfusion, or the rate at which blood moves through tissues in the body

As these features change throughout the menstrual cycle, they help to indicate when ovulation has occurred. For example, body temperature tends to increase after ovulation.

As data is collected month after month, it is run through an app (available for Apple and Android). The idea is that, over time, the app’s algorithm may predict when ovulation might occur, giving you an accurate fertility window that is unique to your own menstrual cycle.


  • It provides an easy, convenient way of tracking fertility.
  • You can get personalized data based on your own physiological signs.
  • It does not require urine, blood, or other more invasive measures for tracking.
  • You do not need to wear it all day.
  • It does not require a doctor’s visit or prescription.
  • It may double chances of conception by aiding with proper timing of intercourse, according to the company.


  • It’s costly and likely not covered by insurance. Some employers may cover it, though.
  • It does not work for people with cycles longer than 35 days. Your cycle might be longer if you have conditions like polycystic ovary syndrome (PCOS).
  • It is not appropriate for people who have pacemakers.
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The tracker and its app are intended to help couples trying to conceive pinpoint their 5-day fertile window when sex may most likely lead to pregnancy. This tracker is intended only to help couples get pregnant. The company says it is not to be used as a contraceptive device, meaning it isn’t approved to prevent pregnancy.

The bracelet has been tested for cycles that range between 24 and 35 days in length. So, if your cycle is shorter or longer than that, it may not be the best choice for you.

It is also not appropriate for you if you wear a pacemaker, as the heart rate data may not be as accurate. Ava may also not be a good match for people who get hives or other allergic reactions with sweating, known as cholinergic urticaria.

Using Ava is relatively easy. You simply put the bracelet on before you plan to go to bed. You sleep with it on. Then you sync the bracelet with the Ava app in the morning when you wake. All the data is collected through the night and is then run through the algorithm to create your fertility analysis that is unique to you.

Step-by-step instructions:

  1. Once you have your bracelet, download the app and then pair the two so they’ll work together. The bracelet needs to be charged for at least 4 hours before the first time you use it.
  2. You’ll wear the bracelet on your nondominant hand and tighten it to the same notch (with one finger-width of space) each time you wear it for the most accuracy.
  3. You can start using the bracelet on any day of your cycle. Just make sure you wear it for at least 4 hours.
  4. When you wake up, you’ll sync with your app to view your data.
  5. As you continue to wear the device cycle after cycle, the data may hone in and best narrow your fertility window.

Ava also allows you to download and print off the last 12 months of data from the app. This can be helpful if you choose to get help from a fertility specialist along your journey.

And once you are pregnant, the app also includes key information to follow your baby’s development for the whole 9 months.

First, you’ll need to order your bracelet. You can do this directly on the Ava website.

The cost for the Basic package, which includes the tracking bracelet, the app, membership to the online Ava community, and free shipping, is $279. There are also Plus and Premium packages ($309, $359) that include an e-book and a full refund if you are not pregnant within 6 to 12 months.

The company does advertise Ava to employers as an alternative to more costly fertility treatments. So, you may want to check with your employer to see if they cover the bracelet either in part or in full.

The bracelet comes with a 1-year warranty. You must be the original purchaser of the device to have the warranty honored. It covers all hardware and accessories that carry the Ava trade name or logo. The company will either refund you for the device, send you a new device, or repair your device.

The Ava website cites some interesting statistics:

  • Upward of 75 percent of couples don’t know when to time sex to get pregnant.
  • Timing sex correctly, presumably using the bracelet, may double chances of pregnancy.
  • The tracker is more effective than strips that measure a surge in luteinizing hormone (LH), known as LH ovulation tests.
  • Some 30 percent of “sub-fertile” women who tried their tracker got pregnant with use within just 1 year.

Sounds too good to be true? A small 2021 study on Ava has shown that the device is indeed accurate when used to identify both fertile and infertile days in the menstrual cycle.

The researchers studied 205 ovulatory cycles from a sample of 61 eumenorrheic women over the course of 6 months and compared the data from Ava with results from LH strips. With regard to fertile days, the algorithms were correct 73.8 to 75.4 percent of the time. With regard to infertile days, the algorithms were correct 90.8 to 93.7 percent of the time.

Another small 2021 study points out that wrist temperature may be more effective than the standard basal body temperature (BBT) method of tracking temperature changes after ovulation. Why? The researchers explain that a single BBT reading cannot compare with the continuous temperature monitoring captured on the wrist overnight. As a result, this method of tracking may lead to better success with getting pregnant.

The Ava bracelet is just one part of a digital health company named Ava Science, Inc., which is based in San Francisco, California. The Ava Fertility Tracker launched in 2016. More recently, it has received clearance from the Food and Drug Administration (FDA).

The Better Business Bureau gives Ava Science a grade of A- while Trustpilot gives the company a score of 4.0 out of 5. What do people think? Well, the reviews are mixed. The app has several thousand reviews in all. It gets a 4.3 out of 5 stars in the Apple Store and a 3.7 out of 5 stars on Google Play.

Reviewers share that the device is easier to use than messy ovulation predictor kits and more convenient than remembering to take BBT at the same time each day. Some others say it may have saved them thousands of dollars on fertility treatments. With regard to customer service, positive reviews point out that the company responds quickly to issues and will replace the band of the bracelet if it breaks, no questions asked.

However, several people feel those more old-school methods may be more accurate in their experiences. Some reviewers chose to do both ovulation predictor kits and the bracelet to compare, and found that their ovulation predictions were off on the app. One woman even had her ovulation predicted for a certain day in the app, but a fertility appointment ultrasound showed she wouldn’t ovulate for a couple more days.

In summary, Ava works very well for some people, but it may not be a solution that works for everyone.

There are a number of other fertility tracking apps, birth control apps, and fertility awareness methods you may encounter in your searches.

Flo, for example, is a fertility tracking app that lets users input information about their cycles. It can track days of spotting, bleeding, cervical mucus, temperatures, and other data. But it does not have a medical device that records any real-time data.

OvuSense is a fertility tracker that records only temperature to use for charting. If you have typical cycles, you can wear the sensor either under the arm or wrist during sleep. If you have PCOS, you can wear it inside the vagina.

Ava braceletFlo appOvuSenseLH testsBBT temperature
Type of devicewearable wrist device plus phone appphone appwearable device, either on the arm or wrist or inside vagina, plus appstrips or tests that require urinea digital thermometer, which can be used on the forehead, ear, or orally
Cost$279$7.99–$9.99 monthly, $39.99–$49.99 yearly$79–$99 ($229–$279 with 12-month subscription to app)variety of options, but ongoing each monthapproximately $7–$40
Results collectorCollects data each night, runs through algorithm to predict 5-day fertile window.Collects data through user input in the app (fertile signs, period days, etc.) and runs through algorithm to predict fertile window.Collects temperature every 5 minutes throughout the night to detect 8-day fertile window.Tests urine for the presence of luteinizing hormone that surges in the days before ovulation.Temperature is taken at the same time each day to look for small variations. A 0.5–1.0 degree rise in BBT is associated with ovulation.
How does it work?Able to gather data continuously over long periods of time to cater information to each individual.Information can be used to either achieve or prevent pregnancy.Vaginal temp option for people with irregular cycles or PCOS.Identifying the actual hormone associated with ovulation is useful for people with irregular cycles.Inexpensive and simple way to track ovulation that is accessible to most people.
DownsidesDoesn’t work for people with PCOS or long cycles.Relies on self-reporting of fertile signs vs. physiological markers, like temperature or LH (though, those items can be added).Sensor is tucked into arm or wrist, not attached, so it may fall out during sleep. Vaginal sensor may be uncomfortable.Must be taken multiple times throughout the month.
Some people, like those with PCOS, may have multiple surges, though.
Temperature may be affected by drinking alcohol, being sick, or other outside factors.
Extra supportAccess to additional resources, like an e-book and community of members.Access to social community of members, expert advice via blog.Access to community support and blog.No outside support.No outside support.

How accurate is the Ava Fertility Tracker?

A small 2021 study showed that Ava may be over 75 percent accurate at determining the most fertile days in the cycle. It may be over 93 percent accurate at determining the days in your cycle when you are not fertile. A press release from the company suggests Ava may be up to 89 percent effective at honing in on the 5-day fertile window each month.

How much does the bracelet cost?

The Basic package of the Ava bracelet costs $279 and includes free shipping. Your employer may or may not cover or reimburse this cost through fertility coverage, but it’s worth asking. Your health savings account (HSA) or flexible spending account (FSA) may be another option to explore.

Which is better, Flo or Ava?

Both Flo and Ava aim to give users a more specific window in which to have intercourse to get pregnant. Flo relies on self-reported information to predict ovulation. Ava relies on physiological markers from the bracelet. Which one is better really comes down to your budget, your cycles (and whether Ava would work for an irregular cycle), and which one you can be consistent with using day after day.

How quickly might I get pregnant using Ava?

The National Health Service says that with having sex every 2 to 3 days throughout the month, around 84 in 100 couples will get pregnant within 1 year without the use of any devices. Ava may help pinpoint the best days to have sex, making this process faster. Successful conception is more complicated than the sperm meeting the egg, however.

That said, when couples time intercourse precisely with their fertile window and ovulation, 38 percent may conceive in the first month, 68 percent in 3 months, 81 percent in 6 months, and 92 percent after 1 year, according to a 2003 study.

Will all couples find success using Ava?

It’s important to point out that Ava has some limitations. It is meant to help couples determine the best times in the cycle to have sex to conceive. If a couple has other fertility issues, including male fertility issues, the tracker may not be of much help.

Around 50,000 couples (and counting) have become pregnant while using the Ava bracelet. While there are many more factors involved than the bracelet itself, it may be worth trying if you are looking to discover when your most fertile days are.

If you have been trying to conceive for over 1 year and you’re under 35 years old, or if you’ve been trying for 6 months and you’re over 35 years old, the American College of Obstetricians and Gynecologists recommends making an appointment with your doctor to discuss other fertility issues that may be at play.