What is the ruling concerning the blood that a wife experienced, especially since a female doctor informed her that it is blood affecting a pregnant woman threatened with miscarriage, and what is the ruling concerning her fasting on the days this blood appeared?

It is correct for the wife to cease fasting during the days she experiences bleeding, as this is menstruation because it occurs at its usual time after a complete period of purity. She must make up the fasts she missed, and there is no sin upon her. Whatever can be considered menstruation is menstruation, and whatever cannot is irregular bleeding (istihadah), bearing in mind that there is no maximum limit for the period of purity.