Is a menstrual period that occurred prematurely due to an error in taking birth control pills considered a normal menstrual cycle in terms of its rulings?

The blood that a woman experiences after childbirth and before the forty-day period (postpartum) is considered menstrual blood. Its rulings are the same as those for normal menstruation, because the default assumption for blood exiting a woman is that it is menstrual blood, unless proven to be irregular bleeding (istihada). So, when menstruation occurs, one must refrain from prayer.