It is narrated from Sayyiduna Ibn Umar (may Allah be pleased with them both) that once Sayyidah Umm Sulaym (may Allah be pleased with her), who was the mother of Sayyiduna Anas (may Allah be pleased with him), asked the Prophet (peace and blessings be upon him) this question: "O Messenger of Allah! If a woman experiences in a dream the same condition as a man does, what is the ruling?" The Prophet (peace and blessings be upon him) said: "When a woman sees water (i.e., discharge) in a dream and experiences ejaculation, then she should also perform ghusl (ritual bath)."
Hadith Referenceمسند احمد / مسند المكثرين من الصحابة / 5636
Hadith Gradingحکم دارالسلام:صحيح لغيره، وهذا إسناد ضعيف لضعف عبدالجبار بن عمر الأيلي .