I was 9 months pregnant. I had 4 fasts qadha of previous Ramadan as well but doctor strictly refused to keep fasts throughout my pregnancy. Should I pay only kaffara takhir or should I keep these qadha fasts as well?

And as for the qadha fasts, am I supposed to pay only fidya and kaffara takhir or am I supposed to keep qadha fasts as well?

So for the month of Ramadan in which you were pregnant and didn't fast, you have to pay qadha and pay fidya. If you were unable to do the qadha till the next month of Ramadan as well, then another kaffara e takhir which is 750 grams of food to a poor person for every missed fast and then give the qadha fast whenever you can.

For the qadha fasts from the previous years which were missed for reason such as haydh then only kaffara e takhir and qadha whenever you can.