Is it permissible for a pregnant woman carrying twins to fast in the fifth month if her doctor permits it, with the understanding that she must break her fast at the slightest feeling of fatigue, and must she obey her husband who believes she should break her fast to prevent harm to her and her fetus?

A pregnant woman does not break her fast merely because of pregnancy. She breaks her fast if she fears harm to herself or her fetus. She ascertains this through experience or by the advice of a trustworthy doctor. If she fears harm, she has a dispensation to break the fast. It is disliked for her to fast if she fears harm, and it may become obligatory for her to break the fast if she fears for her fetus. If she is active and strong, and fasting does not cause her hardship or affect her fetus, then she must fast. If she breaks her fast due to an excuse, she must make up the fast when the excuse is gone. If she does not fear harm, then the husband has no right to order her to break the fast.