It is narrated from Abu al-Sanabil bin Ba'kak (may Allah be pleased with him): Sayyidah Subay'ah (may Allah be pleased with her) (gave birth) twenty-three or twenty-seven nights after the death of her husband. Then, when she became pure from her postnatal bleeding, she desired to marry, and she was censured for it. This was mentioned to the Prophet (peace and blessings be upon him), and he (peace and blessings be upon him) said: "If she wishes to do so, her waiting period ('iddah) has been completed."
Hadith Referenceالمعجم الكبير للطبراني / باب العين / 14150