New Clinical Evidence Supports Tempdrop for Precise Ovulation Detection

Reading time: 3 minutes

By Gemma Rigby

Updated December 29, 2025

Did you know? Tempdrop received a big gold star from science!

We’re excited to share that we published a new peer-reviewed study, confirming what the Tempdrop community has known for years: Tempdrop outperforms other wearables for detecting ovulation and the fertile window.

What was the study about?

Researchers wanted to know:

Can a wearable underarm temperature sensor (Tempdrop) accurately detect ovulation and the fertile window?

To test this, 194 menstrual cycles were analyzed from 125 women who participated in the study using two forms of ovulation tracking:

Tempdrop sensor – a wearable fertility monitor measuring overnight axillary temperature using a proprietary algorithm to estimate the day of ovulation based on basal body temperature patterns.
Clearblue Connected Ovulation Test System – a urine LH ovulation test used as the reference method.

Tempdrop and the Fertility Awareness Method

Tempdrop supports the fertility awareness method by tracking basal body temperature (BBT) throughout the night. Instead of relying on a traditional oral thermometer and strict wake times, the Tempdrop fertility tracker records continuous temperature data while you sleep. This makes BBT measurement more reliable, especially for users with irregular schedules or long menstrual cycles.

What were the results?

The study’s performance numbers were impressively high:

Sensitivity ~97% – Tempdrop detected ovulation in nearly all cycles where ovulation occurred
Specificity ~99% – Tempdrop identified very few “false alarms” when ovulation didn’t occur
Overall accuracy ~99% – the Tempdrop-estimated ovulation day closely matched the LH test result

In simple terms: Tempdrop correctly identified ovulation in the vast majority of cycles, and rarely got it wrong.

Because Tempdrop tracks basal body temperature continuously, users can easily track accurate BBT results daily and identify the temperature rise that confirms ovulation.

On top of that, because it provides a full nightly temperature curve, it can also help evaluate luteal phase quality (the post-ovulation phase when progesterone rises and temperature stays higher). PubMed

Why does this matter in real life?

For anyone tracking fertility (to conceive or to understand their cycle), this study is a big deal because it shows that:

You can sleep through the data collection – say goodbye to those early-morning alarms and strict wake-up times for BBT tracking.
You still get an accurate ovulation estimate.
You also gain insight into your luteal phase, which standard ovulation tests don’t show you.
You can rely on accurate fertility tracking even with irregular cycles, disrupted sleep, or hormonal conditions like Polycystic Ovary Syndrome (PCOS).

Continuous temperature tracking is especially helpful for women with PCOS or long or irregular cycles, where ovulation can be difficult to interpret.

Tempdrop vs. Other Fertility Trackers: What the Evidence Shows

Urine-based LH ovulation tests are considered the gold standard for identifying ovulation timing. These urinary tests detect the luteinizing hormone (LH) surge, while Tempdrop uses basal body temperature tracking to confirm ovulation after it occurs.

However, recent research shows that wearable fertility trackers are becoming a reliable alternative for ovulation detection.

Previous studies have evaluated wrist and ring wearables like Ava and Oura as substitutes for urine ovulation tests. Using a comparable methodology, Niggli et al. reported an estimated accuracy of 93% for Ava's wrist-based fertility tracker. In contrast, Tempdrop demonstrated a higher accuracy of 98.6% for ovulation detection using continuous overnight axillary temperature data.

Similarly, Thigpen et al. examined the Oura ring-based wearable and found ovulation estimation accuracy of 96.4% when compared with calendar-based methods.

While these devices perform well, Tempdrop’s results exceeded both wrist and ring wearables, showing stronger agreement with LH-based ovulation detection.

These findings position Tempdrop as one of the most accurate wearable fertility trackers currently supported by clinical evidence.

The bottom line

Our new publication confirms that Tempdrop’s overnight underarm sensor is:

Highly accurate for detecting ovulation, outperforming leading wearables.
A practical alternative to urine ovulation tests.
A helpful tool for assessing luteal phase patterns.

If you are using Tempdrop as a tool to help you use a fertility awareness method or if you are tracking BBT to conceive naturally, this clinical evidence supports Tempdrop as an accurate, wearable fertility tracker.

For more information, read the full published study below: Shpaichler, Y., Thompson, A., Fromager, B., Vardi, M., & Ecochard, R. (2025). Accuracy of an Overnight Axillary-Temperature Sensor for Ovulation Detection: Validation in 194 Cycles. Sensors (Basel, Switzerland), 25(20), 6327. https://doi.org/10.3390/s25206327