Al-Imām al-Bukhārī narrates: Muḥammad ibn Salām narrated to us; he said: Abū Muʿāwiyah informed us; he said: Hishām narrated to us, from his father, from Zaynab bint Umm Salamah,
from Umm Salamah (may Allāh Almighty be content with her), who said: Umm Sulaym (may Allāh Almighty be content with her) came to the Messenger of Allāh ﷺ and said: “O Messenger of Allāh! Allāh is not reluctant in stating the truth. Is ghusl required for a woman when she has a wet dream?” The Prophet ﷺ said: “Yes, when she sees the fluid.” Umm Salamah (may Allāh Almighty be content with her) covered her face and said: “O Messenger of Allāh! Does a woman also have a wet dream?” He ﷺ replied: “Yes! May your hands be covered in dust! Then how would her child resemble her (otherwise)?”
Reference: Sahih Al Bukhari 130