How many days after a clean period ovulation begins is based on the individual and is usually about a week.
Most people go into ovulation and start ovulating a week after their period is clean. This is only suitable for people who normally have regular periods and have a menstrual cycle of roughly 30 days.
If your period is usually erratic, your cycle is not regular to follow, and the time of ovulation is irregular, you will need to have an ultrasound to monitor ovulation, or use ovulation test strips to monitor ovulation, which is more accurate.
It should be noted that if you have sex during ovulation, the chances of conception are higher. Usually pay attention to the cleanliness of the vulva, if the phenomenon of delayed menstruation, you need to go to the hospital in a timely manner, by a professional doctor to clarify the diagnosis.