Please add! Feel free to divide by category as they come up.
A woman who is pregnant, once the fetus can be discerned, and a breastfeeding woman, do not concern themselves with the times that they previously expected to menstruate (veset kavua). Even if if she had a set time when she would expect her period, she doesn't have to check herself and she is permitted to her husband. And even if she experiences a flow of blood at the time when she would normally expect to bleed, this is considered only coincidental. Once the time of her pregnancy and her breastfeeding passes, she goes back to concerning herself with her original time that she would expect her period (veset). How so? If she had a set date that she would expect her period, for example if she got it on Rosh Chodesh, she concerns herself with the first Rosh Chodesh that comes along. And so too with any other type of time period. And this is true also if she had specific physical symptoms, or a specific time, when she would expect her period. But if she had a time based on intervals, she can't concern herself with it until she starts bleeding again. Once she gets her period, she can concern herself with the interval that she previously experienced.