Hadith 10:1382
Abu Bakr narrated to us, he said: Abd al-Wahhab al-Thaqafi narrated to us, from Khalid, from Ikrimah, regarding [the verse]: "And it is not lawful for them to conceal what Allah has created in their wombs," he said: Pregnancy and menstruation. And Ibrahim said: Menstruation alone.
حدثنا أبو بكر قال نا عبد الوهاب الثقفي عن خالد عن عكرمة @QB@ ولا يحل لهن أن يكتمن ما خلق الله في أرحامهن @QE@ قال الحبل والحيض وقال إبراهيم الحيض وحده