Period Tracking Apps Are Helping Scientists Make Huge Breakthroughs In Understanding Women’s Health

Do you use a period-tracking app? You could be on to something — for your health and for the benefit of science at large. Apps like Clue, Life, and Period Tracker Lite are widely available across different mobile platforms, and their usage is skyrocketing; Clue alone surpassed 5 million users worldwide in 2016. And apart from their benefits for women who track their menstrual cycles and fertility, they're also creating a huge source of data for scientists, with users' consent. With millions of women recording the details of their menstruation in one place, it's a bonanza for researchers looking at the relationship between menstruation and female health, and according to one expert, it looks as if they're already producing breakthroughs.

Clue is particularly invested in collaborations with the scientific community. They have research partnerships with Stanford, Columbia, the University of Washington, and Oxford, all of which are looking at different aspects of the menstrual cycle and female health using Clue data. These partnerships have already led to a study on women's cycles syncing up, and whether it's a myth (their data suggests it is), and there may be new discoveries on the horizon about how menstrual cycles affect everything from STD symptoms to PMS. It's time for an in-depth look at period tracking apps, data, and why they might be the next big thing in understanding female health.

The New Science Uncovered By Period Apps

Clue's latest partnership, with Dr. Alexandra Alvergne of the University of Oxford, may produce some of the most intriguing menstruation science yet. Alvergne, a biological anthropologist, has been using Clue's data on menstruation and other elements of female health to perform two studies, and her preliminary findings, she tells Bustle, have been interesting in the extreme.

Alvergne has been looking at the link between menstruation, inflammation, and the immune system in women. Scientists have known for a while that there appears to be a relationship between immunity and menstruation; differing levels of estrogen and progesterone influence how well the body copes with infection, with the low-progesterone phase of the menstrual cycle, what's called the "luteal phase," being a particularly low point for immune response. So what happens to women's bodies over the course of a cycle when they have an infection?

One of Alvergne's studies aimed to answer whether infectious STD symptoms might be linked to pre-menstrual syndrome, or PMS. She examined a Clue survey of women with STDs to check how the women experienced periods, and if their experiences changed after diagnosis and treatment. The results aren't yet publicly available as they've been submitted for peer review, but she found that women who had STDs (who weren't using hormonal contraception, which can affect menstrual cycles) were much more likely than women without an STD to experience pre-menstrual cramps and headaches. The sample size was very small, at under 100 people, and only looked at two menstrual cycles, but it definitely presents some food for thought.

Her second study, though, is the one that might make waves when it's published. It's also still in peer review, but it's based around the theory that understanding menstruation is essential for understanding female health in general, because menstruating affects us in vitally important and unexplored ways. "Accumulating evidence suggests that in humans, the female immune response is modulated by the hormones governing the menstrual cycle in a way that enables the implantation of a healthy embryo," she explains. We already know that menstrual cycles affect a wide range of illnesses, as she tells Bustle; schizophrenia gets worse during periods, IBS is worse during ovulation, and asthma and diabetes worsen during the premenstrual phase, according to Alvergne. But there's a lot more work to do, and Alvergne proposes that apps like Clue have "unique potential" to help. "I need the research community to listen, now," Alvergne tells Bustle.

Asked to highlight the potential of this sort of cyclical focus on female health, Alvergne says chemotherapy might be one area of research. "Cancer studies never control for menstrual cycle phase," she says. It's completely unknown whether cancer treatments might be affected by what women are at in their cycle, and while the answer might be nothing, it could be a very big deal.

Why Apps Aren't The Answer To Everything

For all their use to scientists, period apps also provide significant limits. For one, they're mostly used by what researchers call WEIRD populations — Western, educated, industrialized, rich, and democratic societies. That doesn't give us much of an insight into the experiences of women outside those places. They're also constrained by the fact that they're self-reporting; women putting their data into Clue, Life or other apps are doing so without medical supervision, and that can make acquiring accurate data difficult. Also, frankly, periods are complicated. “Even to do the research is very complicated, to take into account the many different aspects of the cycles," Alvergne says.

The complicated nature of periods has also been one of the issues with period tracking apps as a whole. The more data we gather, the more it's becoming clear that there may not be such thing as a "normal" menstrual cycle like the one you learned about in health class. They seem to be hugely diverse and influenced by a huge range of factors, and according to a 2017 study out of the University of Washington, period tracking apps on the market seem to find it difficult to cope with cycles that are more "irregular." Study co-author Nikki Lee said in a press release that “The apps are most accurate if your cycles are really, really regular, but the people who most need an app are the people whose cycles aren’t regular." Even period apps' algorithms themselves, it seems, are being caught out by our still-evolving understanding of menstrual science.

So while menstrual cycle apps are definitely doing a lot of good by gathering data everywhere they can (with the users' consent, of course), it's perhaps premature to place the burden of medical discovery on them. For the moment, though, scientists like Alvergne and other partners are using your period to find out more about the peculiar influence of the female reproductive cycle — and that's definitely a reason for you to log all your cramps, bleeds, and sulky feelings as accurately as possible.