Musannaf Ibn Abi Shayba 1:994

994. Humayd ibn Abd al-Rahman narrated to us, from his father, from Abu Ishaq, from al-Harith, from Ali, who said: If a woman sees, after she has become pure from menstruation, something like the washing of meat, or a drop of a nosebleed, or something more than that or less than that, then let her sprinkle water [on her private parts], then perform ablution, and pray. And let her not perform ghusl (full ritual bath) unless she sees thick blood, for it is only a kick from Satan in the womb.