Is it permissible for a pregnant woman to sit and pray if she cannot complete the prostration comfortably, while being able to stand for most of the prayer? And what is the best way to pray while sitting: on a chair or on the ground? And should she stand during the parts that require standing and sit on a chair during the parts that require prostration and descent?

The sick person must perform the pillars and obligations of prayer to the best of their ability, and what they are unable to do is waived for them, according to the Almighty's saying: (So fear Allah as much as you are able). So, they should pray standing if they are able; if not, then sitting. Sitting on a chair or on the ground is permissible, and sitting cross-legged on the ground is preferable. If bowing and prostrating are difficult for them, they should gesture for both, making the prostration lower than the bowing. If they are able to stand, they should gesture for bowing while standing, and for prostrating while sitting. If, during the prayer, the sick person becomes able to perform what they were previously unable to do, they should switch to it and build upon what has preceded of their prayer.