Answered by Shaykh Sohail Hanif, SunniPath Academy Teacher
I have been using a chemical form of contraception for the past 6 months. It has changed my menstrual cycle, but for the first couple months, it was easy to track. However for the past 2 months, I have been bleeding slightly most of the time. I have considered this istihaadah. However, I am confused now as to when I should calculate my haidh. My haidh usually lasts for 10 days, and the purity period in between varies from 16 to 25 days. How do I calculate this?
If one sees constant spotting less than fifteen days apart then it is treated as if one has constant blood flow. In cases of constant bleeding one has to rely on the length of one’s previous menstruation and one’s previous purity period. One need not worry about one’s average’ purity period, just the length of one’s most recent one. One will then assume that the length of one’s last menstrual cycle is one’s menstruation and the length of one’s last purity period is one’s purity and any bleeding seen in that period is to be considered abnormal uterine bleeding (istihada). One will commence this calculation of one’s menstruation from the end of one’s last normal purity. (Radd al-Muhtar)
And Allah knows best.