What is the ruling on fasting the days when light, turbid blood (Kudrah) appears?

The fatwa (definition) we follow states that brownish discharge (kudra) is not considered menstruation unless it occurs during the customary period or is connected to blood. Therefore, your fasting during these days is valid, and you are not required to make up for them if you saw this brownish discharge outside of your customary period. However, if it occurred during your customary period, and the total duration of that period combined with any subsequent bleeding is sufficient to be considered menstruation, then it is menstruation, and you must make up for those days.