The menstrual cycle is regular, the cycle is 28 days, generally ovulation is 14 days after the menstruation, here after the menstruation does not mean after the clean menstruation, it means the 14th day of ovulation when the menstruation sees blood. Generally, ovulation is 14 days before menstruation, which is certain. It is inaccurate to check ovulation speculation, unless menstruation is particularly regular and relatively fixed. Therefore, the only way to check ovulation is to speculate the last menstrual cycle after you have your period, which is 14 days before your period. If you want to have intercourse during ovulation, it is best to do ovulation test paper to monitor which day you ovulate, or you can also go to the hospital to do ovulation monitoring under the Yin ultrasound. There is also a way to take the basal body temperature, when the temperature rises indicates imminent ovulation, ovulation will change with emotional changes, environmental changes or stress, do not use ovulation contraception.