Yevamos 9:4-5

Yevamos 9:4

The following women may not eat terumah: the daughter of a Yisroel who is betrothed to a kohein, pregnant from a kohein, or waiting to perform yibum with a kohein; the same is true of the daughter of a kohein in these situations with a Yisroel. If the daughter of a Yisroel is betrothed to, pregnant from or waiting to perform yibum with a Levi (Levite), or the daughter of a Levi is in one of these situations with a Yisroel, they do not eat maaser (tithes). If the daughter of a Levi is betrothed to, pregnant from or waiting to perform yibum with a kohein, or the daughter of a kohein is in one of these situations with a Levi, she eats neither terumah nor maaser.

Yevamos 9:5

If the daughter of a Yisroel marries a kohein, she may eat terumah. If he dies and she has a son from him, she may continue to eat terumah. If she subsequently marries a Levi, she may eat maaser (but not terumah). If he dies and she has a son from him, she may continue to eat maaser. If she subsequently marries a Yisroel, she may eat neither terumah nor maaser. If he dies and she has a son from him, she may eat neither terumah nor maaser. If her son from the Yisroel dies, she may resume eating maaser. If her son from the Levi dies, she may resume eating terumah. If her son from the kohein dies, she may eat neither terumah nor maaser.