At-Talaq · 65:4

4. As for those divorcées who have no hope in menstruating due to old age, if you doubt in the manner of calculating their waiting period, then it is three months. Likewise, the waiting period of girls who have not reached the age of puberty and hence do not menstruate, their waiting period will also be three months. As for pregnant women, their waiting period after divorce or being widowed is when they give birth. Whoever is mindful of Allah by fulfilling His commands and refraining from the things He has not allowed, Allah will make his affairs easy for him and make easy every difficult matter.