I was wearing Oura, WHOOP & Apple Watch when I got pregnant.
That was how Dr Sian Allen started this fascinating thread on Twitter, further below. No doubt as she continues her 9-month journey more HRV insights will follow.
Background: Dr Allen is a regular and informed HRV tweeter and one of the ones to follow if you are interested in sports/HRV and already know what rMSSD means.
CONCLUSION Body temperature from Oura was the best leading indicator of early pregnancy detection.
Technical Background
Many health and wellness technologies for consumers provide insights and analyses around fertility cycles. To varying degrees the key players, Apple, Oura, Fitbit, WHOOP and Garmin use body temperature, resting heart rate and resting HRV in their algorithms. Other data points are also used. For example, I always thought that (optionally!) logging my sexual activity in WHOOP was a little intrusive, I’m not sure why because no one else could see it apart from me. But that’s how it felt. Dr Allen seems to have taken this to a whole new level and uses some of our favourite tech to record the moment of conception.
More: Very Detailed Ultrahuman Ring Air Review
This post could now go down numerous avenues but let’s just end it and say congratulations to Dr Allen and her partner!
PS I’m not entirely sure if that picture, above, is appropriate or not. It’s from FitGear Hunter’s YouTube channel and he did some work with me on the WHOOP Review, but Hunter looks excited enough about the news too 😉
Must Read: WHOOP Review
Must Read: Apple Watch 7 Review
Here is the Twitter thread with data, it should also show up below!
https://twitter.com/DrSianAllen/status/1488961012464173057
Last Updated on 28 January 2026 by the5krunner
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tfk is the founder and author of the5krunner, an independent endurance sports technology publication. With 20 years of hands-on testing of GPS watches and wearables, and competing in triathlons at an international age-group level, tfk provides in-depth expert analysis of fitness technology for serious athletes and endurance sport competitors.
