Menstrual tracking technologies and fertility: evaluating accuracy, utility, and impact on time to pregnancy

Accurate identification of the fertile window is essential for individuals trying to conceive, yet menstrual tracking modalities differ in precision, accessibility, and clinical utility. This narrative review traces the evolution of menstrual monitoring, from early calendar systems, physiologic observations, at-home hormone testing, to modern digital platforms, and evaluates their efficacy in predicting ovulation. We summarize evidence that tracking behaviors increase fecundability, highlight the limitations in data quality and user experience, and examine device equity, psychological implications, and usability. Understanding the strengths and shortcomings of current tracking modalities can guide clinicians and patients to select approaches that best support their reproductive goals.