When must a woman pray and purify herself after childbirth if bleeding continues for more than 40 days, stops, and then resumes with different colors?

The maximum duration for postpartum bleeding (nifas) is forty days, with no minimum limit. So, whenever a woman experiences purity before the forty days, she should perform ghusl (ritual bath) and pray. Yellowish or brownish discharge after achieving purity from nifas is considered like irregular bleeding (istihada) by some scholars. However, Shaykh Ibn Bāz (Al-Allamah) holds the view that any blood, yellowish, or brownish discharge that appears after childbirth within the forty-day period is considered nifas. If bleeding resumes for a woman within the forty-day period, the Hanbali school considers it doubtful blood, requiring the woman to pray and fast, and to make up any obligatory fasts as a precaution. The more preponderant opinion is that the recurring blood within the forty days is considered nifas. As for any blood that extends beyond forty days, it is istihada, unless it coincides with the woman's regular menstrual period, in which case it is considered menstruation as long as it does not exceed her usual duration; if it exceeds it, then the excess is istihada. The Shafi'i school holds that the maximum duration for nifas is sixty days.