Musannaf Ibn Abi Shayba 9:1559

Hafs ibn Ghiyath narrated to us, from Hajjaj, from Abdullah ibn Zayd, from Ali, who said: The Messenger of Allah (may Allah bless him and grant him peace) forbade that a pregnant woman be had intercourse with until she delivers, or a menstruating woman until she is purified by a menstrual cycle.