Is blood discharged after forty days of postpartum bleeding (nifas) considered blood of irregular bleeding (istihada), as long as its days do not exceed the known days of menstruation?

The majority of scholars hold that the maximum period of nifas (postnatal bleeding) is forty days. A woman in nifas should refrain from prayer for forty days, unless she experiences purity before that, in which case she should perform ghusl (ritual bath) and pray. As for nifas blood that exceeds forty days: if it coincides with her regular menstrual period and does not exceed it, then it is menstruation. Or, if it exceeds her regular period and recurs for three months and does not exceed fifteen days, then it is menstruation. However, if it increases but does not recur, or if it exceeds the maximum duration of menstruation, or if it does not coincide with a regular period and does not recur, then it is istihada (irregular vaginal bleeding).