System and method for determining temperature nadir of a female

A method of determining a temperature nadir during a menstrual cycle of a female human, the method comprising:

• receiving in a processor from a first sensor system of a wearable device a temperature of the female human;
• receiving in the processor one or more further measured physiological parameters of the female human in a current menstrual cycle, wherein the one or more further measured physiological parameters of the female human comprise at least one of:
• heart rate or heart rate variability;
• determining by the processor a detected starting point of a fertility phase of the female human in the current menstrual cycle based at least in part on a change in the one or more further measured physiological parameters of the female human, wherein the detected starting point of the fertility phase is determined based on:
• (i) a defined length of time after a duration of an interval between pulses of the heart rate exceeds a defined threshold value during the current menstrual cycle, or
• (ii) when the duration of the interval between pulses of the heart rate drops below the defined threshold value after the duration of the interval between pulses of the heart rate previously exceeded the defined threshold value during the current menstrual cycle;
• and
• after the detected starting point of the fertility phase, detecting by the processor the temperature nadir as a temporary decrease in the temperature received from the first sensor system, wherein the temperature nadir is detected in a time window after the detected starting point of the fertility phase of the female human in the current menstrual cycle, a time of the temperature nadir being indicative of time of ovulation and peak oestrogen level.

A computer program product comprising a non-transient computer readable medium having stored thereon computer program code configured to control one or more processors of a computerized system, such that the computerized system performs the steps of:

• receiving from a first sensor system of a wearable device a temperature of a female human;
• receiving one or more further measured physiological parameters of the female human in a current menstrual cycle, wherein the one or more further measured physiological parameters of the female human comprise at least one of:
• heart rate or heart rate variability;
• determining a detected starting point of a fertility phase of the female human in the current menstrual cycle based at least in part on a change in the one or more further measured physiological parameters of the female human, wherein the detected starting point of the fertility phase is determined based on:
• (i) a defined length of time after a duration of an interval between pulses of the heart rate exceeds a defined threshold value during the current menstrual cycle, or
• (ii) when the duration of the interval between pulses of the heart rate drops below the defined threshold value after the duration of the interval between pulses of the heart rate previously exceeded the defined threshold value during the current menstrual cycle;
• and
• after the detected starting point of the fertility phase, detecting a temperature nadir as a temporary decrease in the temperature received from the first sensor system wherein the temperature nadir is detected in a time window after the detected starting point of the fertility phase of the female human in the current menstrual cycle, a time of the temperature nadir being indicative of time of ovulation and peak oestrogen level.