Who determined the forty-day period during which a husband is not to approach his wife after childbirth, and why specifically forty days?

A husband is not prohibited from having intercourse with his wife if she experiences purity from post-natal bleeding (nifas), even if it is only one or two days after childbirth. This is because there is no minimum duration for nifas.

However, if the bleeding continues, scholars have differed regarding the maximum duration of nifas:

1. The majority: Forty days. After this, the woman performs ghusl (ritual bath) and prays, and any bleeding thereafter is considered istihada (irregular bleeding). 2. The Shafi'is and Malikis: Sixty days.

The fatwa we follow is that the maximum duration for nifas is forty days.