Is it permissible for a husband married to two women to stay overnight with his pregnant wife at the end of the ninth month in anticipation of childbirth, provided that the other wife is compensated later for the same duration, and is this permissible even if the other wife does not consent?

The default is the obligation of justice between wives regarding overnight stays. It is not permissible to stay overnight with a pregnant wife without the consent of the other wife, except in cases of necessity, such as fearing harm to the pregnant woman and having no helper other than the husband. In this case, he is permitted to stay with her as much as needed, and he must make up the time for the other wife. Scholars have stated that averting harm and nursing the sick are communal obligations (fard kifaya), and sometimes these can become individual obligations. Therefore, a husband staying with his wife whose delivery is approaching due to fear of harm is considered one of the necessities that permit forbidden things. The other wife must be content with this, and she has the right to the same treatment if she is in the same situation.