When does the iddah (waiting period) of a mother whose husband died on the 21st of Dhu al-Hijjah, corresponding to November 18th, end?

If the mother is pregnant, her 'iddah (waiting period) ends upon delivery of her entire pregnancy, based on the Almighty’s saying: "And for those who are pregnant, their term is until they deliver their burdens." If she is not pregnant, her 'iddah is four months and ten days, based on the Almighty’s saying: "And those who are taken in death among you and leave wives behind – they, [the wives], shall wait four months and ten [days]." The 'iddah begins from the time of death, is calculated by lunar months, and the month of death is completed to thirty days if the death occurred within it. Furthermore, it is not permissible for the woman observing 'iddah to travel before her waiting period has ended.