The Obligation of the One Who Broke the Fast in Ramadan to Make Up the Days He Did Not Fast

The questioner: May the Shaykh be respected! What is the ruling on the expiation for breaking the fast for the entire month of Ramadan by a pregnant woman who expected that she would not be able to fast; but she fasted a small amount of it, and she does not count the number of days she did not fast?
The Shaykh: It is obligatory for her to estimate the days she did not fast and fast them.