Are the brown spots that precede menstruation by three days, accompanied by pain and nausea, and appear only in the early part of the day, considered menstruation that necessitates ghusl?

Brown spots, known as "alkudrah," are considered menstruation as long as they are connected to the menstrual period and accompanied by its pains and symptoms, even if they appear intermittently throughout the day. This is because the minimum duration of menstruation is one day and one night. It is not permissible for a woman to pray on this day until she becomes pure.