For women with a regular menstrual cycle, the day of ovulation is 14 days before the next menstrual period. If the menstrual cycle is 28 days, it is on the 14th day after the start of the period. If the menstrual cycle is not 28 days, earlier or later, you need to count backwards. For women with irregular menstrual periods, the calculation of ovulation requires the use of some aids, the simpler of which is to take your basal body temperature. You can also roughly predict the arrival of ovulation based on the change of vaginal discharge during ovulation, which is voluminous, thin and easily stretched. In addition, it is more accurate to monitor ovulation by ultrasound.