Is it obligatory to re-perform the prayers missed due to not knowing that the white discharge (al-qassah al-bayda') is the sign of purity?

Yellowish and brownish discharges are considered menstruation if they are connected to blood. A woman should not perform ghusl (definition) until she sees purity, indicated by one of its two signs: dryness or white discharge. What has been mentioned is correct, as long as the duration of the blood and the connected yellowish or brownish discharge does not exceed fifteen days. If it exceeds that, the woman is considered to have Istihada (non-menstrual bleeding). If the total number of days does not exceed fifteen days, then waiting for purity, as was done, is correct. However, if the duration increases and it becomes clear that the woman has Istihada, there is a difference of opinion regarding the obligation to make up the prayers she missed.