What is the prescribed duration of lochia (nifas), does it cease with the cessation of bleeding or upon the expiry of the determined period, and what is the expiation for intercourse on the thirty-seventh day after childbirth?

The duration of post-natal bleeding (nifās) is forty days; this is the opinion of the majority of scholars. If a woman in nifās experiences purity before the forty days, she should perform ghusl (definition) (ritual bath) and pray. If the blood returns within the forty days, it is still considered nifās. It is recommended that her husband does not approach her during the period of purity that occurs within the forty days until the full period is complete. If a man has intercourse with his wife during the forty days after the bleeding has stopped, there is no expiation (kaffārah) due from him. However, if he has intercourse with her while the blood has not stopped, this is not permissible for him, and he must pay an expiation of one dinar or half a dinar (equivalent to 4.25 grams of gold), along with repentance and seeking forgiveness.