My wife has missed fast in Ramadan either during pregnancy (late stages), breast feeding in its early stages or childbirth during Ramadan. If the missed fast were for valid reasons besides periods, is she allowed to give Kafara for the missed fast.
In the Name of Allāh, the Most Gracious, the Most Merciful.
As-salāmu ‘alaykum wa-rahmatullāh wa-barakātuh.
Your wife will have to keep Qadhaa for the missed fasts, even though for valid reasons. By Kaffara we assume you mean fidya. Fidya can only be paid by one who is suffering from a condition in which he will not be able to fast again.
And Allah knows best
Darul Iftaa, Madrassah In’aamiyyah