Abu Ja'far (may Allah have mercy on him) said: Sayyidah Fatimah (may Allah be pleased with her) lived for three months after the Prophet (peace and blessings be upon him), and after the Messenger of Allah (peace and blessings be upon him) she was never seen laughing, except that people differed over a faint smile at the edge of her tooth.
Hadith Referenceالمعجم الكبير للطبراني / مسند النساء / 19198