Latest Apple Watch Features Period Tracking, AFib Monitoring, and Medication

Jul 07, 2023

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Apple's health features just got a big upgrade with the latest software, watchOS 9, and the new Apple Watch Series 8.

The Apple Watch can work as an electrocardiogram, which can help users monitor their heart rhythm and check for heart conditions. There are also features that can sense if the wearer falls or is in a vehicle crash and calls emergency services for them.

One of the most notable features of the watch is tracking menstrual cycles with wrist temperature sensors. Based on nighttime wrist temperature, the watch can estimate when the user was in their ovulation period and predict the course of their future menstrual cycles.

Apple said the tool can be helpful for family planning. It relies on an age-old fertility monitoring technique that is used both for inducing and avoiding pregnancy.

Here’s what you need to know about the newest Apple Watch health features.

Apple’s ovulation tracker uses a method called basal body temperature. It refers to a person’s body temperature when they're fully at rest and can indicate whether someone has recently ovulated.

Progesterone, a hormone that’s released after ovulation, raises the internal body temperature by about 0.5 degrees Fahrenheit over the course of two to three days after ovulation. If an individual does not become pregnant during this time, the progesterone levels go back to normal, as does basal body temperature, according to Alex Juusela, MD, MPH, FACOG, a board-certified OBGYN at Detroit Medical Center.

If, however, someone has a rise in basal body temperature for 18 or more days, that could be an early indicator of pregnancy.

Traditionally, people using the basal body temperature take their temperature once per day, in the morning, and record it manually. The Apple Watch measures basal body temperature every five seconds overnight, when the body is most at rest. It contains sensors at the bottom of the watch near the skin as well as under the watch display that can detect changes in body temperature as subtle as 0.1 degrees Celsius.

“Basal body temperature recordings are best taken immediately after waking up, ideally at the same time every day. In our hectic lives, this can be difficult to perform. Having a digital thermometer measure one’s temperature during sleep can prevent this logistical problem,” Juusela told Verywell via email.

The ovulation detection feature is meant to help with family planning, but it’s not cleared as a form of birth control.

The basal body temperature method is one of the least effective birth control measures. The Centers for Disease Control and Prevention said up to 23% of women using fertility awareness methods get pregnant over a year of use. Besides, this method doesn’t protect against sexually transmitted infections.

“I warn patients who do not desire pregnancy against interpreting a rise in basal body temperature as a guarantee that unprotected intercourse will not lead to pregnancy,” Juusela said. “There are many reasons why basal body temperature can rise and ovulatory cycles are not always regular.”

A key issue when using wearable devices for tracking health data is ensuring that the data remains private. In the wake of the Supreme Court’s decision to overrule Roe v. Wade, the landmark ruling that protected abortion rights, there is concern that data collected on period tracking apps could be weaponized against people whose pregnancies are terminated.

Apple said that all of a user’s data is encrypted when their iPhone is locked with a passcode, Touch ID, or Face ID. All health data backed up to iCloud is encrypted in servers as well as when being transferred from the device, according to the company. Apple uses end-to-end encryption, so it does not have the key to decrypt the data.

But for users who are trying to become pregnant, the Apple Watch can help predict when they’re most fertile—usually, about two to three days before their temperature rises during ovulation. The more they track their cycle, the better the Apple Watch can become at predicting when they will ovulate and when the best days are to have sex to increase their chances of becoming pregnant.

“If you’re trying to conceive, knowing if and when you ovulated can inform your family planning with your healthcare provider,” Sumbul Desai, vice president of health at Apple, said during the launch event.

The new Apple technology can also note if there are abnormalities in a user’s menstrual cycle, such as irregular or prolonged periods. Unusual temperature shifts could be a sign of health conditions like fibroids or polycystic ovary syndrome (PCOS).

The updated Apple devices now include a feature that allows users to manage and keep track of their medications, vitamins, and supplements.

Users can set up a custom schedule for each medication and note how often they must take it. Their phone or watch will send a reminder when it’s time to take their medication.

Additionally, using their iPhone camera, users can upload an image of their medication’s Rx label. The Health app will share information about potential drug-drug interactions with other medications and life factors, such as alcohol consumption, they have recorded in the app.

The new watches update a feature to notify users when they experience atrial fibrillations (AFib), an irregular heart rhythm that can lead to palpitations, shortness of breath, and even stroke or heart failure.

The feature is cleared by the Food and Drug Administration for people 22 years and older with no history of AFib.

The health app also contains information about factors that may influence a person’s risk of AFib based on their alcohol consumption, exercise, sleep, and other lifestyle factors.

Many Apple Watches will notify people when their heart rate gets too high or too low. Newer versions contain an electrocardiogram (ECG) app. When a user receives a notification of an irregular rhythm, or skipped or rapid heartbeat, they can take an ECG and manually record their symptoms. If the symptoms align with a serious condition, the Watch will prompt them to call emergency services.

Users can easily print a PDF of their AFib and other health history information to be shared with health providers.

Talk with a health provider if you have questions about whether wearable technology can help you reach your health goals, or if you are seeking ways to track your fertility or reproductive health without the use of wearable technology.

Su HW, Yi YC, Wei TY, Chang TC, Cheng CM. Detection of ovulation, a review of currently available methods. Bioeng Transl Med. 2017;2(3):238-246. doi:10.1002/btm2.10058

Centers for Disease Control and Prevention. Contraception.

Goeckenjan M, Schiwek E, Wimberger P. Continuous body temperature monitoring to improve the diagnosis of female infertility. Geburtshilfe Frauenheilkd. 2020;80(7):702-712. doi:10.1055/a-1191-7888

By Claire BugosClaire Bugos is a health and science reporter and writer and a 2020 National Association of Science Writers travel fellow.