Is it obligatory for a woman to make up a day of fasting in which she saw a drop of blood but did not experience menstrual bleeding due to menstruation being interrupted by medication?

It is permissible for a woman to take medication to prevent menstruation, provided certain conditions are met, though it is preferable to avoid it. A single drop of blood is not considered menstruation by the majority of scholars, in contrast to the Maliki school. Therefore, fasting on the day a drop of blood appears is valid according to the majority.