Is a woman's fast valid if she is making up for missed Ramadan fasts and experiences yellowish discharge during her menstrual period, knowing that she did not see blood and did not stop praying?

The majority of scholars hold that the maximum period of nifas (definition) (post-natal bleeding) is forty days. If the bleeding exceeds this, it is considered istihada (non-menstrual bleeding), unless it coincides with the woman's regular menstrual period, in which case it is considered menses (hayd). If a woman sees blood after the forty days and it coincides with her usual menstrual period, then it is hayd. As for yellowish discharge (sufra), nothing is entailed by it, based on the statement of Umm Atiyyah: "We did not consider yellowish or brownish discharge after purification to be anything [of significance]."