A few days after menstruation is clean, ovulation occurs.

Ovulation period can not be calculated according to the number of days after menstruation is clean. Under the condition of normal menstrual cycle, ovulation period is located in the first 14 days or so of next menstrual cramps. Women with inaccurate menstrual cycle cannot calculate ovulation period in this way. They can also calculate ovulation period by using test paper. Ovulation period can also be calculated by abdominal color Doppler ultrasound and Yin ultrasound.