If you have any doubt concerning those of your wives who have ceased menstruating, then you should know that their waiting period will be three months, and the same will apply to those who have no menstruation due to young age or a disease. As for those who are pregnant, their waiting period will end with delivery. Allah will ease the hardship of those who fear Him.
Meaning:-
Waiting period: is the period a woman must observe after the death of her spouse or after a divorce, during which she may not marry another man. Its purpose is to ensure that the male parent of any offspring produced after the cessation of a nikah (marriage) would be known.