Wearable sweat sensor tracks reproductive hormones to forecast ovulation
A new skin patch measures oestrogen and progesterone levels in sweat, potentially offering a less invasive way to predict ovulation than blood tests or ultrasounds. In a small study, the patch accurately detected hormonal changes, and researchers believe monitoring both hormones together could provide a fuller picture of the menstrual cycle. The device uses a mild electrical current to induce sweating and sends results to an app.
The patch’s design addresses a key challenge in sweat analysis: variability in pH and salt content. By incorporating a dried buffer that rehydrates upon contact with sweat, the sensor normalizes the sample before measuring hormone levels, improving accuracy. In testing, the device required only about 9 microlitres of sweat and delivered results to a smartphone app within roughly 90 minutes, making it a practical option for at-home monitoring.
The study involved nine women, including those of reproductive age and postmenopausal participants. Correlations with blood tests were strong—0.83 for oestradiol and 0.93 for progesterone—suggesting the patch could reliably track hormonal shifts. A separate 28-day trial on three women showed that detected changes aligned with expected menstrual cycle patterns, supporting its potential for longitudinal fertility tracking.
This technology could reshape how individuals manage reproductive health, offering a non-invasive alternative to clinic-based tests. People trying to conceive may gain more frequent, accessible data on ovulation timing, potentially reducing stress and healthcare visits. However, its accuracy in broader populations—including irregular cycles or hormonal disorders—remains unproven, and reliance on app-based interpretation could introduce user error. Widespread adoption may also raise privacy concerns about sensitive health data transmitted digitally.