What should a woman in nifaas do if she sees a yellow discharge?

Whatever discharge is passed by a woman following childbirth comes under the same rulings as the blood of nifaas, whether it is regular blood or a yellow or brownish discharge, because it is within the usual timescale of nifaas, until the forty days are over. Whatever comes after that, if it is regular blood and there have been no interruptions in the flow, then it is the blood of nifaas, otherwise it is the blood of istihaadah (vaginal bleeding that is not menstrual or nifaas), etc.