<s>[INST] I am trying to get pregnant so have been following my fertile times for couple of months, my period normally lasts 5 days but this time it has lasted 11 days. Would my fertile time be at the same time as if it has been a normal period or at a different time ? [/INST] HI, I understand your query & concern.  Fertile period is 3 days before & after the ovulation day. As ovulation day is day when mature ovum is released from ovary ready for conception.& ovulation is 14 days before the expected date of menstruation. (In 28 days cycle it is 14th day of menses) Occasionally when menstrual cycle is disturbed due to hormonal disturbance. (like you have this time a prolonged menstruation). The beginning of menstrual cycle itself may get late & so fertile period will vary.  You can judge your ovulation by- -half a degree decline in basal body temperature. Is indication of ovulation.  - LH surge test indicates ovulation in 24- 36 hours of +ve test.  Thanks. </s>