It is narrated from Sayyiduna Abu Hurayrah (may Allah be pleased with him) that the Messenger of Allah (peace and blessings be upon him) forbade ghilah (intercourse with one's wife during the period of breastfeeding), then he said: "Has it harmed Persia and Rome?" Ghilah is that a man goes in to his wife while she is breastfeeding a child.
Imam al-Tabarani (may Allah have mercy on him) said: "No one narrated this hadith from Umar bin Abi Salamah except Abu Awanah, and Layth bin Hammad is alone in narrating it."
Hadith Referenceالمعجم الأوسط / باب الميم / 5134
Hadith Gradingمحدثین:إسناده ضعيف لضعف ليث بن حماد
Hadith Takhrij«قال الهيثمي: فيه ليث بن حماد وهو ضعيف «مجمع الزوائد ومنبع الفوائد، ج 4، ص 298»»