<s>[INST] hi doctor,i would like to know when will i ovulate after eating duphhaston since there is no enough time to ovulate in between ..i ate dupaston  two times a day for 5 days,my periods came after 4 days of finishing the course but bleeding was vry light,why?? [/INST] Hi, How are you doing ? Let me tell you how tab. Duphastone works. Day 1 of periods is first day of bleeding. For a lady of 28 days periods, ovulation will be on Day 13-16, following ovulation, progesterone hormone will be released from the remains of follicle. Only if this hormone is released for 14 days, you will get good thickness of inner lining of uterus & you will have good bleeding on time. Duphastone is same as Progesterone hormone. All you need is have tab. Duphastone once at night from Day 15 for 10 days. You will have periods 7-10 days after stopping the hormones. Your bleeding was light, as dose of hormones was for less time. Duphastone will not affect ovulation. It only causes periods by acting on uterus inner lining. Hope I have clarified your query, do write back if any queries All the best Chat Doctor.  </s>