Answered by Shaykh Amjad Rasheed
When does divorce end: on the first day of the following period of purity or on the first day of the menstruation that follows three periods of purity?
The waiting period (Ar. ‘iddah) of a woman who menstruates ends with the start of her third menstruation. As soon as a woman in waiting sees [m: menstrual] blood after her third period of purity, her waiting period is over.