I like to consider myself a tech-savvy millennial. I’ve got all the apps, I doom-scroll with the best of them, and I was an early adopter of that weird phase when everyone was making their photos look like they were taken in 1977. But there’s something particularly strange about opening my phone each morning and having an algorithm tell me whether or not I’m fertile today.
It started innocently enough. After going off hormonal birth control—a whole saga involving migraines, mood swings, and one particularly memorable crying jag over a pet food commercial—I decided I wanted to “get in touch with my natural cycle.” God, even typing that makes me cringe a bit. But there I was, 32 years old and realizing I had absolutely no idea what my body was up to without pharmaceutical intervention.
So I did what any modern woman would do: I downloaded an app. Not just any app, mind you. I researched. I read reviews. I compared features. I ended up choosing one with a soft pink interface and cute little icons that promised to help me “understand my unique cycle” through the “power of data.” It had a 4.8-star rating and over 30,000 reviews. Surely 30,000 menstruating people couldn’t be wrong?
The first few days were a bit like getting a new fitness tracker—oddly exciting. I diligently logged everything the app asked for: period start date, flow heaviness (the icon for “heavy” was hilariously dramatic, like a crime scene), mood, sleep quality, cervical mucus consistency (yep, we’re going there), basal body temperature, and about fifteen other symptoms I’d never paid attention to before.
“Do your breasts feel tender?” the app would ask, and I’d think, “I dunno, do they?” before poking myself experimentally in the chest while waiting for the kettle to boil.
“Rate your energy level from 1-5,” it would prompt, and I’d stare blankly at my screen trying to remember what normal energy even feels like. Is being able to both work AND make dinner a 3 or a 4? Is wanting to nap under my desk at 2 PM standard operating procedure or a sign of fatigue?
By the end of the first month, I had essentially created a comprehensive dossier on myself that even my gynecologist doesn’t have. The app knew when I’d had headaches, when I’d felt bloated, when I’d been constipated, when I’d been in the mood for sex, and when I’d wanted to murder strangers for walking too slowly in front of me at Tesco.
And then came the predictions.
“Your fertile window will begin in 3 days,” the app announced one morning, with the confidence of someone who had actually examined my ovaries rather than just processed the data points I’d fed it.
“How do you know that?” I whispered to my phone, both impressed and slightly unnerved. I hadn’t even gotten out of bed yet, and already an algorithm was making pronouncements about my reproductive system.
The next day, the app sent me a notification: “Remember to log your cervical mucus today!”
I was in a meeting when this popped up on my screen. Thankfully my phone was face-down, but still, it felt like a bizarrely intimate interruption. Here’s Kate from accounting talking about quarterly projections, and meanwhile, my phone is nudging me about bodily fluids.
By month three, I had developed a strange relationship with the app. I was checking it first thing every morning, sometimes before I’d even properly woken up. It would tell me what day of my cycle I was on, predict my mood, and inform me whether today was a day to “avoid intercourse” or “ideal for conception” (neither of which applied to my perpetually single status, but thanks for the reminder, app).
The weird thing is how quickly I began to trust it. When the app told me I would start feeling pre-menstrual symptoms on a particular Wednesday, I found myself thinking, “Oh, so THAT’S why I feel off today.” Even though I’d felt perfectly fine until I read the notification.
One evening, I was out with my friend Mia, who’d recently started using the same app.
“It’s uncanny,” she said, sipping her wine. “Yesterday the app told me I’d be especially creative during my follicular phase, and then I had this amazing brainstorming session at work.”
“Do you think you had a good brainstorm because your hormones were actually optimal for creativity, or because the app suggested you would?” I asked.
She paused, glass halfway to her mouth. “Huh. I don’t know.”
That’s when I started noticing the placebo effect in my own interactions with the app. If it told me I was likely to have low energy on a particular day, I’d feel tired. If it predicted increased libido, I’d suddenly notice attractive people on my commute. The app was creating a feedback loop—telling me how I should feel, which influenced how I actually felt, which I then dutifully logged, further training the algorithm to predict that same pattern.
Around month five of this experiment in digital body literacy, things got even weirder. The app started serving me targeted ads. Suddenly my feed was full of supplements “specifically formulated for your luteal phase,” fertility-friendly lubricants (again, single), organic cotton tampons, cycle-syncing meal plans, and something called “womb healing meditation downloads.”
I’d essentially handed over the most intimate details of my biology to a for-profit company that was now trying to sell me things based on that information. And I’d done it voluntarily. Eagerly, even.
The breaking point came on a Tuesday in August. I’d been feeling a bit off all day—crampy, irritable, bloated. Classic PMS symptoms. But according to my app, I wasn’t due to start my period for another week. For the first time, I found myself doubting my own bodily sensations because they didn’t align with what the algorithm predicted.
“Maybe I’m just stressed,” I thought. “The app knows my cycle better than I do at this point.”
Two hours later, I got my period. A full week “early” according to the technology that was supposedly tracking my unique patterns.
I stared at the app in betrayal. After months of meticulous data entry, after sharing literally every twinge and mood swing and night of poor sleep, the algorithm had gotten it completely wrong. And worse—I had trusted it over the actual physical symptoms I was experiencing.
That night, I found myself going down an internet rabbit hole about fertility apps. What I discovered wasn’t exactly comforting. A 2018 study had evaluated 73 fertility apps and found that most of them had either no scientific evidence backing their methods or were based on outdated research. Another study showed that even the most accurate apps only correctly identified the fertile window about 21% of the time.
Twenty-one percent. You’d literally have better odds flipping a coin.
And yet millions of people use these apps for everything from avoiding pregnancy to trying to conceive. We’re making major life decisions based on technology that, statistically speaking, is wrong more often than it’s right.
The real kicker? I started looking into what happens to all that intimate data we’re feeding these apps. Most of them have privacy policies that would make your hair curl. Several popular fertility apps have been caught sharing user data with third parties including Facebook, Google, and various marketing companies—often without clear consent from users.
One app was even sharing information with the user’s employer about their fertility intentions. Imagine your boss knowing you’re trying to get pregnant before you’re ready to disclose that information.
I thought about all the things my app knew about me. Not just when I menstruated, but when I had sex, when I was stressed, when I didn’t sleep well, when I had digestive issues or headaches or mood swings. I had essentially created a comprehensive health profile of myself and handed it over to a commercial entity with virtually no regulation or oversight.
The next morning, I deleted the app.
It felt oddly liberating, like cutting off a clingy friend who texts too much. But I also felt a bit lost. I’d outsourced awareness of my own body to an algorithm for so long that I wasn’t sure I remembered how to pay attention to it myself.
So I bought an actual paper calendar and started keeping track the old-fashioned way. Just basic information—period start and end dates, and any particularly notable symptoms. No more obsessive logging of every twinge and mood fluctuation.
It’s been four months now, and something interesting has happened. Without the app telling me what to expect or how to feel on any given day, I’ve actually gotten better at noticing patterns myself. I can tell when I’m approaching my period because my body gives me clear signals—if I pay attention to them.
I’ve also realized how much anxiety the app was causing me. The constant notifications, the pressure to log every symptom, the feeling that I was somehow “doing it wrong” if my experience didn’t match the predictions—it was exhausting. Not to mention the weird burden of knowing that incredibly private information about me was floating around in a database somewhere, possibly being shared with God knows who.
Don’t get me wrong—I still use plenty of health tech. My fitness tracker counts my steps, my meditation app guides my breathing, and I’ve got at least three different applications to remind me to drink water throughout the day. But there’s something different about outsourcing awareness of your reproductive cycle—something more fundamental and personal.
Maybe some people find these apps genuinely helpful, and I’m not here to judge that. But for me, the experiment in algorithmic body awareness taught me something important: no app knows my body better than I do. It just took deleting one to remember that.
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