It is narrated from Sayyidah Khawlah bint Hakim (may Allah be pleased with her) that she asked the Messenger of Allah (peace and blessings be upon him) about a woman who sees in her sleep what a man sees. He (peace and blessings be upon him) said: "Nothing is required of her, just as nothing is required of a man as long as he does not ejaculate."
Hadith Referenceالمعجم الكبير للطبراني / مسند النساء / 20983