Contraceptive effectiveness of a digital contraceptive with a wearable device vs an oral thermometer

PURPOSE: To inform contraceptive decisions, we aimed to compare the pregnancy and continuation rates of a digital contraceptive, when paired with temperature data from wearable devices versus from oral thermometers. MATERIALS AND METHODS: We employed prospectively collected data from women who registered to Natural Cycles for contraception between the 1st of August 2022 and the 1st of September 2024. Using Kaplan-Meier curves, we calculated 13-cycle pregnancy rates in typical and perfect use as well as one-year continuation rates. We estimated the association of known demographic characteristics with pregnancy rates using a multivariate Cox proportional hazards model. However, when adjusting for demographics, measuring with a wearable device rather than a thermometer was not independently associated with pregnancy. We observed one-year continuation rates of 75.8% for wearable device users and 56.4% for thermometer users. CONCLUSIONS: Findings from this study suggest that combining a contraceptive app with a wearable device rather than an oral thermometer does not affect pregnancy rates when adjusting for socio-demographic variables. However, the substantial increase in continuation implies greater user convenience.