The period of postnatal bleeding is forty days

Sayyiduna Uthman bin Abi al-As (may Allah be pleased with him) narrates: I heard the Messenger of Allah (peace and blessings be upon him) say that he (peace and blessings be upon him) had set forty days as the period of postnatal bleeding for women.
If this chain is sound, then it is a sahih (authentic) mursal, because Imam Hasan al-Basri's hearing from Sayyiduna Uthman bin Abi al-As is not established.

It is narrated from Sayyiduna Abdullah bin Amr (may Allah be pleased with them both) that the Messenger of Allah (peace and blessings be upon him) said: "A woman in postnatal bleeding should wait forty nights. If she becomes pure before that, she is pure; and if she exceeds forty days, she is in the position of a woman with istihadah: she should take a ritual bath and pray, and if the blood overwhelms her, she should perform ablution for every prayer."
Amr bin al-Husayn and Muhammad bin Ulathah do not meet the condition of the two Shaykhs, but I have mentioned it as a supporting report.

It is narrated from Sayyiduna Mu'adh bin Jabal (may Allah be pleased with him) that the Prophet (peace and blessings be upon him) said: "When seven days have passed for a woman in postnatal bleeding and she then sees purity, she should take a ritual bath and pray."
Imam Muslim cited Baqiyyah bin al-Walid as supporting evidence, and al-Aswad bin Tha'labah is a well-known Syrian narrator; however, this hadith is gharib (unusual) in this chapter.