Wearable thermometers for symptothermal method charting

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На сайте часть 1 of this 2-part series on temperature-taking tools for symptothermal method charting, we covered oral thermometers. Here in part 2, we cover wearable thermometer options. Keep in mind that, as we noted previously, all of the исследование done on the effectiveness of the symptothermal method used an oral (or vaginal) thermometer, with women taking their BBT immediately upon waking up [1]. Wearable BBT technology is still relatively new, so it hasn’t been directly studied in conjunction with a specific fertility awareness method yet. 

При этом, несколько исследования показать promising data on the effectiveness of using wearable technology to record BBT and accurately pinpoint ovulation [2][3][4]. If you’re considering buying a wearable device, make sure to consult the brand’s page on their effectiveness, as some devices have done their own unique studies.  

As in part 1, each wearable device listed will have a description of how it is used, its pros and cons, plus a price comparison to some of the other tools. The options are nearly endless when it comes to BBT-measuring devices, but here are some of the most common ones.

Tempdrop

Tempdrop is a wearable BBT thermometer that you wear while you sleep. It is a small teardrop-shaped monitor that sits inside an elastic armband, resting on the inside of your upper arm near your armpit. Tempdrop was one of the first BBT wearables on the market and recently celebrated its tenth anniversary. 

This device works by recording your temperature continuously throughout the night, determining what your true lowest body temp is. Even if you wake up during the night, Tempdrop will sense this and use its algorithm to still give you an accurate BBT reading. This feature makes it especially popular among women who are frequently waking with a baby in the middle of the night, or who experience uneven sleep.

Once you wake up, all you have to do is sync your device with the app and your BBT reading will appear. You can either use Tempdrop’s app to chart (which has both a free and premium version with extra features) or sync your data to another app.

Another popular feature of Tempdrop is that it uses its algorithm to slowly figure out your body and know whether or not a BBT reading is accurate or an outlier. This allows your charting to remain consistent and filter out disturbances, such as a mild sickness or having a drink before bed. Beyond this, the Tempdrop app only gives interpretations of fertility status if you’ve upgraded to the Premium version, which could be a drawback if you want a little more guidance. 

Стоимость

Tempdrop’s newest model is priced at $219 and includes a fabric armband. A yearly subscription to the Premium version of their app (which is not necessary to chart) is $36. 

Incora earring

Incora Earrings are a new, high-tech pair of earrings which measure BBT amongst a host of other biomarkers including sleep, heart rate variability, oxygen saturation, and more. Though as of this publishing they are not available for purchase yet, they are currently undergoing final testing and are set to be available sometime in 2025. 

Incora’s biggest advantage is that users won’t need to remember putting them on at a certain time, as they can be worn all day and night (they are expected to have a two week battery life). Their website boasts both detailed sleep tracking with BBT charting, plus fitness tracking that allows you to use синхронизация циклов to align workouts with your menstrual cycle. This could be a game-changer for women who are interested in both fitness and fertility awareness. 

The main drawback of Incora earrings is that they are not available for purchase yet, so we only have limited information about how they work and their effectiveness. In the meantime, you’re able to sign up to participate in their клиническое испытание or ask to be on the waitlist for release. 

Стоимость

According to third-party источники, Incora Earrings will cost $250 a pair once released.

Кольцо Oura

Another high-tech jewelry option is the Кольцо Оура, which is the only option on this list that can be used by both women и men. The Oura Ring is a wearable thermometer but it’s much more than that. It’s a smart ring that is worn at all times (not simply at night), and tracks a number of biomarkers—including BBT, sleep variability, heart rate, and stress. It integrates with other apps (like NaturalCycles, Flo, or Clue) for cycle tracking, and gives you insights on when your period should begin, but doesn’t predict ovulation for you. Another interesting feature in their women’s health section is that it will track your gestational age if you are currently pregnant, giving you health insights for your current week of pregnancy. 

Oura is wildly popular, largely because it gamifies health. Users receive sleep scores when they wake up, plus readiness and activity scores throughout the day. You’re able to use these scores to up your fitness (or sleep) game, or you can share them with an in-app social media feed. The Oura app will even remind you to stretch or meditate if it senses you are highly stressed. 

Depending on who you are, you might love or loathe all of this detailed health information constantly at your fingertips. As a BBT tracker, Oura works similarly to others like Tempdrop, but offers many more features and customization. 

Стоимость:

Oura rings start at $299 or $349, depending on the style you choose, and include one free month of their premium app membership, which unlocks the full range of Oura features. Premium membership costs $5.99/monthly after the trial period. 

Ava Bracelet 

Ava Bracelet is most similar to the Tempdrop in that it is only worn at night, but looks similar to a smart watch as it is worn on the wrist. It tracks BBT while sleeping, then uses a computer algorithm to determine a fertile window which it displays in an app, akin to NaturalCycles.

An important distinction between Ava and the other devices, however, is that Ava only markets itself as a way to получить pregnant, not as a device for charting to avoid pregnancy. On the product’s webpage, Ava говорит that their device is only right for you if you are “not intending to use Ava as a form of contraception.” Ava does not specify why this is, simply stating that their algorithm only identifies days that it is likely for a woman to get pregnant, rather than days that it is возможно. That being said, you май still be able to use the BBT data from Ava to chart using a separate method of FAM in order to avoid pregnancy (keeping in mind, again, that the effectiveness data for sympto-thermal methods utilizes oral temps, so proceed with caution). 

Women with uneven cycles might also not want to choose Ava, as their webpage штаты that it only works for users who “have a cycle length within a range of 24 to 35 days.”

Стоимость:

A unique выгода of Ava is that they have a program for employers to cover Ava Bracelets for employees, utilizing it as a fertility-supporting device rather than immediately jumping to covering assisted reproductive technologies like IVF via employer-sponsored health insurance. If you’re looking for a BBT tracker to try to conceive and have an employer that covers fertility devices—you may be able to get the Ava Bracelet for free! If not, Ava Bracelet costs $279 with no other fees associated. 

OvuSense

Finally, the OvuSense is the last wearable thermometer on our list and the most unique—it is not worn on your arm or finger, but instead inserted vaginally like a tampon while you sleep. The benefit behind this is that the temperature is very accurate, since vaginal temps are more similar to oral than a skin-measured reading. 

OvuSense also uses an app and an algorithm, with both ovulation prediction и confirmation, meaning that the app will show once it believes you are no longer fertile. It only requires 6 hours of continuous wear to be accurate, so it is also a good option for those with broken or shorter sleep. Another benefit of Ovusense is that it specifically purports to help those with PCOS with comprehensive PCOS symptom management tools and an algorithm which recognizes the longer and more irregular cycles common to PCOS. 

A potential drawback of Ovusense is that it might be harder to remember to use it, especially if you are traveling. It might also not be a preferable option for postpartum women who are still healing after birth, and might not want to insert a device vaginally. Other potential concerns include cleansing (tampons, which are also worn internally for hours on end, are thrown away after one use), infections (another risk of tampon use) and damage to the vaginal mucosa. The Ovusense сайт notes that “As with the use of tampons, there may be a small risk of toxic shock.  However, the risk of toxic shock is lowered by only using the sensor when you’re not bleeding. The sensor is also made of anti-bacterial medical grade silicone which you wash daily – that discourages the growth of bacteria which can lead to toxic shock.”

Стоимость:

Ovusense costs $99 for the sensor and one month of their app, or $279 for the sensor and one year of their app, plus three months where you can access a free fertility nurse consultation. 

What about the Apple Watch?

If you own any version of the Apple Watch Ultra или an Apple Watch Series 8 or later, you may be aware that it can estimate when ovulation happened based on wrist temperature data from while you were sleeping. You might wonder whether you can just use that data for your basal body temperature charting with the symptothermal method. To be clear, the Apple Watch is не considered a wearable thermometer. From Apple’s support page “The temperature sensing feature is not a thermometer and cannot provide wrist temperature measurements on-demand.”

A word on data privacy and wearable thermometers

Seamless transition of health data from thermometer to app is a major selling point for multiple oral and wearable options. The rapid evolution of femtech (consider that Tempdrop is a veteran brand on the market, at just 10 years old!) may have outpaced data privacy and security in some cases, and we would be remiss not to include a ‘buyer beware’ word of caution. For those interested, we’ve written more on this topic здесь. Though no one reads the fine print for fun, before you sign up for an app or purchase a smart temperature device, be sure you know what types of your health data will be used by the company–and how. 

Remember: you need to tell your app when you’re fertile, not the other way around

Lastly, while some of the oral and wearable thermometers we discussed in parts 1 and 2 of this roundup on smart temperature-taking devices for fertility awareness charting may make algorithm-driven predictions about when you will ovulate, hear this: Your phone (specifically, the apps on it) cannot tell you when you are or are not going to be fertile. Your real-life observations, including basal body temperature readings, are the most accurate way to identify when your fertile window is opening and closing. This is why it’s key—no matter what method you choose and how high- or low-tech your charting tools are—that you learn how your body works, plus how to use your chosen method from a подготовленный инструктор.

Ссылки:

[1] Frank-Herrmann P, Heil J, Gnoth C, Toledo E, Baur S, Pyper C, Jenetzky E, Strowitzki T, Freundl G. The effectiveness of a fertility awareness based method to avoid pregnancy in relation to a couple’s sexual behaviour during the fertile time: a prospective longitudinal study. Hum Reprod. 2007 May;22(5):1310-9. doi: 10.1093/humrep/dem003. Epub 2007 Feb 20. PMID: 17314078.

[2] Shilaih M, Goodale BM, Falco L, Kübler F, De Clerck V, Leeners B. Modern fertility awareness methods: wrist wearables capture the changes in temperature associated with the menstrual cycle. Biosci Rep. 2018 Nov 30;38(6):BSR20171279. doi: 10.1042/BSR20171279. PMID: 29175999; PMCID: PMC6265623.

[3] Zhu TY, Rothenbühler M, Hamvas G, Hofmann A, Welter J, Kahr M, Kimmich N, Shilaih M, Leeners B. The Accuracy of Wrist Skin Temperature in Detecting Ovulation Compared to Basal Body Temperature: Prospective Comparative Diagnostic Accuracy Study. J Med Internet Res. 2021 Jun 8;23(6):e20710. doi: 10.2196/20710. PMID: 34100763; PMCID: PMC8238491.

[4] Maijala A, Kinnunen H, Koskimäki H, Jämsä T, Kangas M. Nocturnal finger skin temperature in menstrual cycle tracking: ambulatory pilot study using a wearable Oura ring. BMC Womens Health. 2019 Nov 29;19(1):150. doi: 10.1186/s12905-019-0844-9. PMID: 31783840; PMCID: PMC6883568.