What is the meaning of the Companion Sumayyah bint Salamah pledging allegiance to the Messenger of Allah, peace and blessings be upon him, regarding what was in her womb, and his saying to her: "You are the freest of free women"?

The report about Su'ad bint Salama asking the Prophet, peace be upon him, to pledge allegiance to her for what was in her womb, and his saying to her, "You are the freest of free women," is a weak report with no chain of narration. What is well-known regarding the pledge of allegiance by women is what Aisha, may Allah be pleased with her, narrated, which is that the Prophet, peace be upon him, used to test the believing immigrant women with the verse: (O Prophet, when believing women come to you pledging to you), and he would say to them, "I have pledged allegiance to you," without his hand ever touching the hand of any woman. If the weak report were to be confirmed, the apparent meaning would be that Su'ad wished to pledge allegiance for herself and her fetus, and the Prophet, peace be upon him, informed her that she was a chaste, free woman and that what was in her womb was her son from her husband.