What is the ruling regarding my pregnant wife's fasting in the last month of Ramadan, what is the expiation for her not fasting, and is Zakat or anything else incumbent upon me?

If a pregnant wife is able to fast and it does not harm her, then she must fast. However, if she fears for herself or her fetus, then she is permitted to break her fast and must make up the days later, based on the Almighty's saying: "But whoever is ill or on a journey - then an equal number of other days."

If her breaking of the fast is solely out of fear for the fetus, then in addition to making up the days, she must feed a poor person for each day she misses, according to many scholars. The expiation (feeding a poor person) may be obligatory upon the husband's wealth according to some jurists, because he is the guardian of the child. If the feeding is obligatory upon the wife, it is permissible for the husband to feed on her behalf with her permission.