Sunan at-Tirmidhi (Jami-al-Tirmidhi), Chapter: Taharah (Purification)

reported that the Prophet (SAW) was asked about a man who noticed moisture on his garment on awakening from sleep but does not remember the nocturnal dream, he said that he must have a bath. He was also asked about one who remembers a nocturnal dream but his garments have no moisture. He said that he need not have a bath. Sayyidah Umm Salamah (RA) asked, "O Messenger of Allah (SAW) Shall a woman, who has this experience need have a bath?" He said, "Yes. Women are like men." [Ahmed26255, Abu Dawud 236, Ibn e Majah 612]