The Swedish physicist revolutionising fertility awareness

I have slightly altered the headline of the BBC news report. The story first came to my attention through the "Once a physicist" feature in July 2017's Physics World. That story was headed as follows:

Elina Berglund is the chief technology officer and co-founder of Natural Cycles - a fertility app that helps women to prevent, plan and monitor pregnancies. As a physicist, she was part of the team that discovered the Higgs boson at CERN in 2012.

The Physics World feature gives an indication of the particular contribution that Elina Berglund's background in physics has made to the development of her algorithm, and what may constitute a novelty in relation to other natural methods (corrections on this point via the comments box please if necessary). The use of temperature as an indicator of the fertile time in a woman's cycle is itself well known, but it is the improved analysis of the data that may make this app a genuine innovation.

I was in a stable relationship and I did not want to use hormonal contraception anymore. We looked into "natural family planning solutions", but there was nothing out there that was easy and reliable to use. Such a solution is prone to human errors if you analyse the data yourself; while the few devices that were available were outdated, expensive and, most of all, used simplistic algorithms. Using my statistical and programming skills from analysing data in particle physics, I developed an algorithm that analyses a woman's body temperature to detect ovulation and pinpoint fertile and non-fertile days. Although the algorithm was at first only for my own use, I quickly realised that this was something many women wanted and needed. Several of my physics colleagues started measuring their own temperatures as well and sending them to me to run my algorithm and give them a "green" or a "red" day. My husband, also a physicist, suggested we turn the algorithm into an app, so that all women and their partners could benefit from this innovation.

Physics World's feature also suggests that the reason for the temporary revoking of regulatory approval was essentially technical. It had to do with whether their app was classified as a fertility monitor, which required one regulatory classification, or as a contraceptive device, which required a different regulatory classification. It achieved this second regulatory classification in February 2017.

Elina Berglund's own experience of using the app is within her own marriage, something that clearly indicates a particular context in which it is going to be more effective. It is also a context that significantly reduces the criticism that using the app does not protect against sexually transmitted infections, as women with single sexual partners are much less exposed to such a risk.. The app is clearly going to be less helpful for a woman whose lifestyle involves multiple sexual partners, both from the point of view of STI protection and from the point of view of the willingness of partners to respect a "red" day.

An interesting aspect of the app is the way in which it responds to the data of an individual woman as more data is entered. It adapts to the individual's cycle, rather than imposing a single algorithm on to the data. The potential of the app to monitor a pregnancy, not fully described in the media coverage, might also have interesting application to the care of women in remote locations in less developed countries .... can a medical professional access the woman's data via the app from a different location?

Natural Cycles website is worth exploring, particularly the reviews from users which, leaving aside the question of whether the app is used primarily to achieve contraception, show an appreciation of a better understanding by women of their own bodies.