When menstruation is irregular, how to calculate the ovulation period appropriately

Patient's question:

All will be delayed by 7 to 10 days. I want to know how I should estimate my ovulation period like this. Is there any sister who knows?

Doctor's answer:

The first day of ovulation = the shortest menstrual cycle days minus 18 days
The last day of ovulation = the longest menstrual cycle days minus 11 days
Before using this formula to estimate, it is recommended that the individual observe and record their menstrual cycle for 8 consecutive times to determine the longest and shortest days of their cycle. Substitute these values into the above formula to obtain the dates when the woman's "ovulation period" begins and ends.
The recurrence of gynecological diseases severely harms women's health. Patients should pay attention to maintaining external genital hygiene in daily life and avoid sexual activity. Finally, it is hoped that female patients can receive proper treatment.