What is the required period of mourning for a woman whose husband has died, and how long is the period during which she is not permitted to leave her home or spend the night elsewhere?

The waiting period ('iddah) for a widow: If she is pregnant, her 'iddah is until she gives birth. If she is not pregnant, her 'iddah is four months and ten days. The evidence for the non-pregnant woman is the Almighty's saying: (And those of you who die and leave wives behind them, they shall wait concerning themselves four months and ten [days]). And the evidence for the pregnant woman is that Subai'ah al-Aslamiyyah gave birth after the death of her husband, and the Messenger of Allah, peace and blessings be upon him, said to her: "You are lawful, so marry whom you wish."