Nicole Nguyen and Cordilia James, Wall Street Journal:
Different types of data, including information that can be subpoenaed from period trackers, can create an extremely detailed profile of you when combined. Prof. Fowler says she thinks it is likely that user data will have greater importance if more places criminalize abortion.
While period trackers collect and store health data, there aren’t typically special protections governing that information, said Prof. Fowler. Apps can use your data how they choose as outlined in their privacy policies, she said, adding that ideally the data would be stored on your devices — rather than in the cloud — and not be subject to third-party tracking.
Period tracking apps’ sometimes sketchy privacy policies and the legal jeopardy in which they can place users is something explicitly called out in Sen. Elizabeth Warren’s announcement of a bill to curtail data brokers.
Apple’s first-party Health app is the only one that encrypts users’ data end-to-end. Unfortunately, it is halfway between an all-in-one health tracking app and a repository for other apps’ data. I do not have experience with entering a menstrual cycle, but I find manually adding cycling distance or — new in iOS 16 — medication to be confusing and inelegant.
Even if a period tracking app is sharing data with Health, it is worth remembering that its own in-app privacy and data use policies apply.