Update: iOS 9 introduced menstruation tracking to the Health app.

Apple has released iOS 8, which includes the Health app. Health is meant to be a central place where you can get an overview of your health and fitness, with data provided either by third-party apps, the Health app itself, or manually by the user.

The release of HealthKit (the developer framework for integrating other apps with Health) is delayed due to bugs, but the Health app is already available.

Before the new operating system was released, I was really interested in the Health app already, but something was missing from the promotional materials: tracking menstrual cycles. Maybe “John Appleseed” doesn’t menstruate.

When I checked the documentation for HealthKit to see how cycle tracking data can be integrated into the Health app from third-party sources, I was disappointed to find out that Apple did not include anything related to menstruation and the reproductive health of roughly half of the world’s population.

In case you’re wondering whether Health is only concerned with a few basics: Apple has predicted the need to input data about blood oxygen saturation, your daily molybdenum or pathogenic acid intake, cycling distance, number of times fallen and your electrodermal activity, but nothing to do with recording information about your menstrual cycle.

So why is tracking cycles important to health management?

I wanted to know more about whether people keep track of their cycles in any way, and why they do it, so I made a short survey about it. Eighty four people responded, of whom 89% have experienced menstruation, so the sample is small. The answers were interesting nonetheless.

Of my small sample 43% currently track their cycles, but two in three responded that they have done so in the past.

Of those who do not track, some respondents can predict when their next menstruation is likely to begin, either due to their contraception method dictating when it will occur (34%), or one in five through other means (potentially being able to read changes in the body signifying cycle stages, but I didn’t ask for details). Multiple answers were allowed, so there may be overlap between those groups.

Menstruation, changes in menstruation, or lack of menstruation can be signs of other health problems. One of the respondents to my survey only menstruates when they are ill due to treatment they had in the past, for example.

Things that could be signs of abnormalities:

Menstruation that’s too frequent

Menstruation that’s not frequent enough

Length of menstruation

Length of cycle

Blood loss level

Bleeding between periods

Bleeding after menopause

Post-coital bleeding

However, those characteristics can be perfectly normal for some individuals, and this knowledge sometimes comes by tracking past data and seeing patterns on a larger scale. Especially in cases where one’s individual cycle characteristics are uncommon it can be harder to detect changes without tracking different aspects.

Migraines, for example, can be triggered by periods (or more accurately, falling oestrogen levels just before menstruation), so it’s useful to be able to predict when it’s likely that your ability to work will be affected.

For the majority of those who answered my survey, the reasons for tracking were mainly detecting irregularities (68% of people picked this answer), knowing when to purchase sanitary items (81%), and learning about one’s cycle (52%).

Many respondents mentioned the effects of their cycle on other areas of life.

I can predict my cycle in my head, but I want info relevant to the momentary state of my health, like a body-weather report, e.g. “likely to be achey today; try for extra water and sleep”

Commonly mentioned is the ability to plan work and leisure activities away from days which are likely to be very painful.

ALL the period tracking apps are trying to get me pregnant. I just want to know if I need to pack my cup on a weekend trip and when the first day of my last period was so I can book paps

Checking that contraceptive methods work was also mentioned as one of the reasons for recording cycles, whether the respondent used barrier protection, UID or hormonal methods.

In many cases, health professionals will ask you about the date of your last period. There are many reasons for this. One is to detect variations from the norm as previously mentioned. Knowing the cycle pattern might be useful to detect various health problems and any unwanted effects of medication. It’s common to arrange or adapt body examinations depending on the stage of the menstrual cycle (e.g. colposcopy, cervical smear, breast and pelvic examinations, urine tests).

Emergency health workers will ask about your last period so they know whether they should act as if there’s a possibility of pregnancy, in which case some treatments can be withheld or substituted. This is the kind of information that should have found its way onto Apple’s Medical ID so it could be made available to emergency services.

‘“How are you?” now has a really accurate answer.’ — unless you menstruate

The average age of the first period is thirteen years, and last one on average happens when the person is fifty-one years old.

I wanted to know how many people are of menstruating age at any given time. Worldwide data from the US government census for 2013 is banded by age groups, so to be err on the side of caution I’ve selected ranges between 15 and 49 as the menstruating ages. Of course not all of those people will actually menstruate, but I hope that the difference is insignificant.

By this estimate, over 1.8 billion people are currently of menstruating age. That’s just over a quarter of the population. If you also include people who have menstruated or are yet to menstruate then of course that number is approaching half the world’s population. That’s a huge potential audience, of whom a large proportion might be interested in recording their cycles at some point in their lives.

Tracking cycles isn’t anything new, it has been done since the dawn of time, in many different forms. I am pretty sure it was the first ever occurrence of Quantified Self movement, although for reasons I cannot understand cycle tracking doesn’t feature very prominently in it.

So why hasn’t Apple included it in Health?

Apple did take the lead on something they thought was important even though it didn’t affect a high percentage of the user base: accessibility. It was so important that making apps made with built-in components are accessible by default, without the developer needing to know anything about accessibility. Apple took care of it, because it was the right thing to do, not because it was the killer feature that everyone demanded.

In the same way, the iPhone includes the Stocks app by default, because Apple clearly decided that checking stocks is a very important thing to do. I couldn’t find any data on the total percentage of the population that owns stocks, but I can’t imagine it’s bigger than the percentage of people with disabilities or a menstrual cycle.

Perhaps it’s because Health is intended to collect data from sensors rather than manually input information? Apple explicitly states that manually entered data is to be collected too:

HealthKit makes it easy for apps to share health-related information, whether that information comes from devices connected to an iOS device or is entered manually by the user. (source)

In addition, there are already many apps designed for tracking periods, although many of my survey respondents mentioned that they’re too gendered (there were many complaints about colour schemes, needless ornamentation and twee language), difficult to use, too focused on conceiving, or not taking into account things that the respondents wanted to track.

So why isn’t cycle tracking present in the Health app? Maybe there is a good reason, or maybe it didn’t occur to anyone to include it.