The present disclosure relates to a method and a system for determining the fertility status of a female. The method comprises the steps of determining and recording a continuous series of temperature data points over a menstrual cycle relating to a body temperature of the female, identifying if the series of temperature data points comprises at least one feature in the series of temperature data points and, if a feature has been identified, determining a point in time of ovulation based on a pre-determined relationship between the feature and ovulation. The feature can be a break in homogeneity of the menstrual cycle, and/or a particular pattern of temperature readings which may occur within a particular timescale and which may be determined by pattern analysis (see figure 5). The temperature is preferably measured using a flexible pessary device inserted into the vaginal channel, which forms part of the system of the invention.
