Sayyidah Umm Hani' (may Allah be pleased with her) narrates: "Whenever I looked at the belly of the Prophet (peace and blessings be upon him), the only thought that came to me was of sheets of paper (qaratis) laid one upon another."
Imam al-Tabarani recorded it; its chain contains a narrator, Jabir al-Ju'fi, and he is da'if (weak).