Periods are the blood outflow that adolescent females experience once a month. There are instances where people have dreamt of menses in the dream, here is the meaning of such dreams in Islam.
1- According to Ibn Sirin رحمة الله عليه, the greatest dream interpreter of Islam, having periods in a dream means that the dreamer would earn ram money proportional to blood flow.
2- If a man sees that his wife has gotten periods then it means that he would be facing troubles to complete his business/tasks and jobs in this world.
3- If a man sees that his wife has been free of periods in a dream and has taken a bath then it means that he will be blessed in worldly affairs.