Musannaf Ibn Abi Shayba 1:1008

Ma'n ibn 'Isa narrated to us, from Malik ibn Anas, from 'Abdullah ibn Abi Bakr, from his paternal aunt, from the daughter of Zayd ibn Thabit, that it reached her that women used to call for lamps in the middle of the night to look for the sign of purity (the end of menstruation). She used to criticize them for that and say, "The women did not use to do this."