Should a woman pray if blood continues to flow irregularly for 10-12 days after her menstrual period, and is this considered istihada (non-menstrual vaginal bleeding)?

If a woman completes her customary period [of menstruation] and then experiences bleeding again before fifteen days [have passed], this is istiḥāḍah (non-menstrual vaginal bleeding) which does not prevent prayer or fasting. However, if the interruption occurs before her customary period is complete, she must complete her customary period, and only then is she considered to be in a state of istiḥāḍah.