What is the ruling on fasting and prayer after the intermittent bleeding that follows the observation of the substance of purity, subsequent to the insertion of an IUD and the use of birth control pills?

Any blood a woman sees before fifteen days have passed since the first flow of blood is considered menses. Pink is one of the colors of blood. The period of purity intervening between the two blood flows is a valid purity. Consequently, fasting on the aforementioned Friday is not valid, and similarly for the day she saw a pink color; she must break her fast on that day and perform ghusl when she sees purity.