What is the legal ruling regarding conjugal relations with one's wife after the cessation of postpartum bleeding, followed by the reappearance of a few drops of blood?

A woman's purity from menstruation and postpartum bleeding (nifas) is achieved either by dryness (al-jufūf) or by the white discharge (al-qaṣṣah al-bayḍāʾ). Women's customs vary in this regard. So, for a woman whose custom is to attain purity with both, and she experiences dryness alone, she should wait for the white discharge until the end of the chosen prayer time. However, a woman whose custom is to attain purity by dryness alone should not wait for the white discharge. The confirmed dryness occurs when the cloth comes out untainted by blood, turbid discharge, or yellowish discharge. If purity occurs at night, it is recommended for the husband not to have intercourse until she completes the forty days, but there is no sin or expiation if intercourse takes place. As for the drops of blood that return after ghusl, they are still considered part of nifas, and ghusl is obligatory after they stop and complete purity is achieved.