The messy reality of tracking one’s menstrual cycles has evolved alongside the dawn of personalized technology. What was once only listed down has now been replaced by period-tracking applications, some of which have up to 77 million users monthly.
While these platforms reduce the need for manual, burdensome monitoring to just mobile phone notifications, entrusting them with personal data comes at a cost. When misleading privacy policies and inaccurate health standards seem prevalent among these applications, does this newfound overreliance only push women further from genuine clinical assurance?
The illusion of the 28-day default
For many women, the primary appeal of period-tracking apps is their predictive power. Yet, this power is often built on a shaky foundation of “regularity” that does not reflect biological reality for some. Amsterdam-based researcher Blaithin O’Brien notes that many of these tools assume that every user follows a standard 28-day menstrual cycle. In reality, menstrual cycles can naturally vary anywhere from 21 to 35 days.
The 28-day assumption frequently overlooks the wide spectrum of menstrual health. For women whose bodies do not conform to this rigid default, an app’s predictive power becomes less a health tool and more a digital calendar. O’Brien flags the repercussions of this fixed cycle, positing that “many apps don’t account for the fact that some users are infertile, or struggle with fertility.” She highlights that most mass-produced apps lack medical oversight during its development, failing to account for the complexities of infertility or the nuances of hormonal fluctuations, which causes predictions to be flawed.
Furthermore, these apps seem to lack any semblance of effectiveness for women with irregular menstrual cycles. Obstetrician-gynecologist Agnes Soriano-Estrella mentions that a period-tracking app may recognize the 40-day cycle and accurately predict when their menstruation will begin, which can lead to a misconception that this is normal, “without really knowing that 40 days is not normal,” she explains.
Wanted: Professional input
While she sees the utility of apps in providing patients with a menstrual record, Soriano-Estrella still raises red flags on the complacency users may develop from their perceived “accuracy” of the software program. She notes that while some apps attempt to learn from a user’s history, they lack the nuanced computation of a medical professional.
Doctors conduct individualized assessments to establish a patient’s “range of regularity” before determining fertile windows. Some information that may be needed are the start date of the last menstrual period, flow intensity, or duration of the cycle. However, Soriano-Estrella emphasizes that the importance of certain data varies, depending on the patient’s symptoms or medical concerns.
Hence, she underscores the continuing relevance of medical consultations to determine which symptoms to observe, rather than placing blind trust in an app’s unverified utility, as it often fails to distinguish between a “consistent” cycle and a “healthy” one. “We have to be sure that they are reliable. And we can only do that if we consult health professionals before putting our trust in them,” she asserts.
Accuracy is the standard period-tracking apps strive to meet, but often fall short of. For Leira Comia (I, AB-OSDM), who has used Flo since 2023, the app is helpful but not flawless. “I wouldn’t say it’s entirely accurate,” she admits, especially because her cycle can sometimes be irregular. Some months, the prediction is off by only a day or two; other times, it fails to match her cycle’s actual progression. Even with years of logged data, the app still does not fully adjust to her body’s irregularities.
Health professionals emphasize that these platforms still need improvement in accuracy, inclusivity, and data safety. Soriano-Estrella asserts that apps should go beyond predicting dates and flag patterns that may signal health concerns. “If they can put some measures to say that this is an alarming thing already and you have to consult [a doctor], then that would be most useful for the patient,” she explains.
Beneath the digital cycle
Privacy risks add another layer to the issue. Research shows numerous period-tracking apps collect and share user information, sometimes without clear consent and disclosure in their data policies. O’Brien notes that “many apps can operate freely while violating data privacy regulations,” leaving users vulnerable to exploitation of their personal health information.
Both O’Brien and Soriano-Estrella raised concerns about how these apps use personal data. In August last year, a California jury found Meta, the parent company of Facebook and Instagram, liable for collecting information stored by Flo users. O’Brien also cited a study which found that 30 period-tracking apps with a cumulative 200 million downloads sent data—including personal information—to Facebook. Of these apps, 66 percent reportedly failed to disclose data sales in their privacy policies.
Despite these controversies, users continue to rely on these apps because they often feel they have few reliable alternatives. Comia says she still uses Flo despite the issues. “I’m still using it to this day kasi I have no other application to migrate to,” she states.
The shortcomings of period-tracking apps often stem from their rigid design. O’Brien contends that these apps should not operate on a fixed cycle model, but instead allow users to adjust patterns to their own bodies. She also stresses that platforms should recognize that “not everyone is fertile or interested in childbearing” and allow users to opt out of pregnancy-related information.
Even with more inclusive design, these platforms cannot replace medical expertise. Algorithms may estimate patterns from logged data, but they cannot fully comprehend the biological realities behind menstrual health. Hormonal variation, underlying conditions, and individual physiology remain factors that technology alone cannot interpret. Ultimately, these apps’ insights remain mere estimates and not substitutes for professional care, as no software can fully account for the intricacies of the human body.
This article was published in The LaSallian’s March 2026 issue. To read more, visit bit.ly/TLSMar2026.
