What is the ruling on one who missed days of Ramadan for three consecutive years due to pregnancy, breastfeeding, and a surgical operation, thinking that expiation (kaffarah) abrogates making up (qada'), and does not remember the number of days, knowing that she paid money instead of feeding the poor?

Transitioning from making up missed fasts to feeding the poor is only for those who are unable to fast due to an illness from which recovery is not expected. As for the sick person whose recovery is expected, it is obligatory for him to make up the fasts after he recovers. If recovery from the illness is expected, then feeding the poor is not sufficient, and it is obligatory to make up the days that were missed. If the exact number of days is not known, then one must fast the number of days that he is certain are obligatory, and fasting the greater number is more cautious and absolves one's responsibility more completely.