Musnad Abu Ya'la al-Mawsili 110:165

Abu Bakr narrated to us, Yahya ibn Adam narrated to us, Sharik narrated to us, from al-A'mash, from Mujahid, from Ibn Abbas, who attributed it to the Prophet (may Allah bless him and grant him peace): That he forbade the eating of every beast of prey having fangs, and the killing of children, and the selling of war booty. He said: And I think he said: And [he forbade] that pregnant women be had intercourse with.