Chapter: "For those who are pregnant, their 'Idda is until they laydown their burdens."

(the wife of the Prophet) A lady from Bani Aslam, called Subai'a, become a widow while she was pregnant. Abu As-Sanabil bin Ba'kak demanded her hand in marriage, but she refused to marry him and said, "By Allah, I cannot marry him unless I have completed one of the two prescribed periods." About ten days later (after having delivered her child), she went to the Prophet (ﷺ) and he said (to her), "You can marry now."

that his father had written to Ibn Al-Arqam a letter asking him to ask Subai'a Al-Aslamiya how the Prophet had given her the verdict. She said, "The Prophet, gave me his verdict that after I gave birth, I could marry."

Subai'a Al-Aslamiya gave birth to a child a few days after the death of her husband. She came to the Prophet and asked permission to remarry, and the Prophet (ﷺ) gave her permission, and she got married.