Sayyidah Aishah (may Allah be pleased with her) relates that the Messenger of Allah (peace and blessings be upon him) would be praying while I lay in front of him (peace and blessings be upon him). Shu'bah said that Sa'd said: I think Aishah (may Allah be pleased with her) also said that she was menstruating.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصلاة / 3494