In the wake of the leaked Supreme Court draft decision suggesting that Roe v. Wade is imperiled, many took to social media encouraging women to delete apps that help them track their menstrual cycles. Countless messages and memes circulated on social media telling women to “Delete your tracking apps NOW!”

The clear implication was that the apps could or would be used by law enforcement to identify and prosecute women who had undergone abortions, if indeed the landmark decision is overturned. The warnings didn’t—and didn’t need to—describe the mechanism by which this would be accomplished; it was concerning enough that a long-held protection might be stripped away.

But amid the fear, questions were raised about how dangerous the tracking apps were, what private information would or could be revealed should law enforcement get their overreaching hands on it. Data scientists began taking a closer look at the nature of what the digital trail would be.

There are many such apps, one of the best-known being the Flo Ovulation and Period Tracker. This program, with over 230 million users, helps women plan the beginning and end of their cycle and understand their bodies better, tracking various symptoms, mood swings, and energy levels at each stage. For those trying the get pregnant the app helps identify the days of greatest fertility, and for those who become pregnant offers easy tracking of the due date, benchmarks for healthy babies, information about newborn care, and so on.

However the tracked data can’t reveal which pregnancies were ended without a live birth—by abortion or for any other reason. At most it might tell someone if a woman was pregnant at one point, but most pregnancies end in miscarriage. In fact, according to a 2018 study by William Rice, an evolutionary biologist at the University of California, Santa Barbara, for women in their twenties conception is as likely to end in miscarriage as it is in a live birth. An article in ScienceAlert added, “Many women don’t even know they’re pregnant initially; and, since most miscarriages happen in the first 12 weeks of pregnancy, many miscarry without even knowing it’s happening…. And, because the miscarriage rate only rises with age, the number of miscarriages far outnumber live births, his analysis asserts: ‘It is not an abnormality. It’s the norm.’” The person digging into the tracking app data would have to do individual-level follow-ups to see whether a given pregnancy resulted in a live birth.

In sum, it seems that the apps could be a threat if someone accessed the data, looked through the hundreds of millions of users, compared them to live births for those same people, and then (somehow) investigated to see why the pregnancies that didn’t end in live births happened. Even in the cases where an abortion is suspected, you’d have to show that the woman didn’t get it legally via mail or in another state.

How Big Is the Threat?

Government surveillance and privacy threats are real, and while it’s certainly possible that period tracking apps could at some point be used to prosecute women seeking abortions, experts don’t highlight it as a likely threat—and if anything obscures more serious privacy concerns.

Carly Page of TechCrunch was one of the first tech writers to address the nascent concern. In her article she cast a skeptical eye on the utility of period tracking apps. She notes that while “widely shared fears are by no means unfounded, it’s unlikely that self-reported menstrual cycle data will fall into the hands of authorities and lead to widespread hunts for people who seek an abortion or who previously got one.”

“For starters, there’s the issue of accuracy. Period-tracking apps are often erroneous, and a person’s menstrual cycle is sensitive to a number of external factors such as exercise, stress, medications and even family drama. Experts agree that information such as the day of ovulation and the fertile window can only be predicted precisely if using a marker of ovulation, such as basal body temperature or ovulation sticks, and a 2018 study found that the accuracy of prediction by menstrual cycle apps was no better than 21%. This means that there’s a lot of reasonable doubt surrounding this data, which ultimately means it’s unlikely going to be accepted as evidence in a U.S. court setting, where ‘beyond a reasonable doubt’ is a legal standard of proof required to validate a criminal conviction.”

Page notes that

“While it’s unlikely the sensitive data you share with your period-tracking app is going to end up in the hands of those seeking to outlaw abortion, that’s not to say these tools don’t have extensive privacy problems, including the aforementioned issue of sharing your personal data with third parties. A 2020 Consumer Reports investigation examined five popular period tracking apps—BabyCenter, Clue, Flo, My Calendar and Ovia—and found that they all shared user data with third parties for marketing and other purposes… For some, period-tracking apps can be incredibly useful tools; not only can they empower people by helping them to learn more about their body and how it changes with their cycle, but any recorded irregularities could potentially be a sign of hormonal, thyroid or hematologic issues. And while the risks associated with the lax privacy of some of these apps have been highlighted in response to the reported plan to overturn Roe v. Wade, the majority of these aren’t limited to period-tracking apps. Most of the other apps installed on your smartphone also collect data—including your location—that can identify where you go, who you meet and what you do.”

In her recent piece, New York Times opinion columnist Zeynep Tufecki cast light on the many digital windows that could reveal a possible pregnancy—or the end of one. She notes that “Women are urging one another to delete phone apps like period trackers that can indicate they are pregnant. For example, algorithmic interpretations of Instagram posts can effectively predict a person’s future depressive episodes — performing better than humans assessing the same posts. Similar results have been found for predicting future manic episodes and detecting suicidal ideation, among many other examples. Such predictive systems are already in widespread use, including for hiring, sales, political targeting, education, medicine and more. Given the many changes pregnancy engenders even before women know about it, in everything from sleep patterns to diet to fatigue to mood changes, it’s not surprising that an algorithm might detect which women were likely to be pregnant. Many such algorithmic inferences are statistical, not necessarily individual.”

Jane Hu, writing for Slate, also highlights the long and convoluted road between ovulation prediction information and abortion prosecution based on that data:

“So, yes—it is possible menstrual app data could be used to prosecute people. But just because it’s possible doesn’t mean it will become common. For one, it might be cumbersome for law enforcement to obtain that data. In a statement to Slate, popular app Clue said it is ‘obligated under European Law to apply special protections to our users’ reproductive health data. We will not disclose it.’…  Plus, there are easier ways of gathering evidence. ‘The types of digital data that have been used in court thus far suggest it’s going to be much more simple digital info used against us,’ says Cynthia Conti-Cook, a civil rights attorney and technology fellow at the Ford Foundation. ‘It’s going to be info from [our] own devices, often words we have typed into the screen, info we ourselves have been involved with co-creating.’ In the end, Hu notes that “Google searches, texts, and your web history would likely paint a fuller picture of your life than the date of your last period. If prosecutors are trying to charge people for having abortions, or behaving in ways that would have led to a miscarriage, they would need to establish intent (e.g., Googling ‘abortion clinic near me’) or evidence of your behavior, which they might find in texts or photos.”

Forget your period-tracking app; that text or email to or from your doctor or abortion clinic is far more useful for someone trying to find out if you’ve had the procedure.

Lauren Barack tackled the topic for New Scientist, asking India McKinney of the Electronic Frontier Foundation for her bottom line. Echoing other experts, McKinney cautions against throwing the baby out with the bathwater, and “understands the urge to delete period trackers but says that is akin to not buying a car because you don’t want someone breaking into it on the street. Instead, she suggests being thoughtful about what you post, pick apps with privacy guarantees you agree with and reject an app’s request to use location data. Navigation apps need to know your location, but an app tracking ovulation probably doesn’t.”

Delete Or Not: A Personal Choice

In the end, the consensus seems to be that period-tracking apps per se do not pose an unusually high threat to their users compared to other common apps. Women—or, really, anyone—who are concerned about fully guarding their digital privacy should consider deleting any apps and cookies that could in some way compromise their safety (along with the standard suggestions about two-factor password authentication, using a Virtual Private Network, keeping antivirus software updated, and so on).

For hundreds of millions of women these apps provide useful information that helps them plan their lives and monitor their attempts to get pregnant (or not). There’s no right or wrong answer, though the blanket advice that all women should delete their period tracking apps may do more harm than good—and may offer a false sense of protection. Technology offers tradeoffs; for example disabling your iPhone’s tracking helps protect your privacy—but also makes it more difficult to recover if it’s lost, or help others find you in an emergency. Whether women choose to continue using the apps or not, that decision should be made based on facts instead of fears.