Must one make up the days of not fasting in Ramadan due to a miscarriage, knowing that bleeding occurred before the miscarriage and one did not break their fast at that time?

The ruling on abortion is that if a mistake occurs, there is no sin in it. If the fetus has formed, then what is necessary applies to it. If it has not formed, then nothing is required for its abortion.

As for the abortion blood that comes down with an unformed fetus, it is considered dysfunctional blood (dam fasad). The woman should not abandon prayer or fasting for it. "Formed" (al-takhalluq) here means that the human image appears, even if subtly, detectable only by experts. Some scholars define this as after eighty days, while others say that formation begins after forty days.

Therefore, if you broke your fast on the days when blood came down after the fetus fell, it is safer to make up those days. As for the blood that came down before the fetus fell, it is dysfunctional blood (dam fasad), and fasting is obligatory with it. If you broke your fast during it, you must make up the fasting days.