Abstract: A hot and cold pack for breast treatment for pregnant women is provided. The hot and cold pack for breast treatment for pregnant women includes a cover including a through hole in a center thereof, through which a user's nipple passes, and having an annular shape of which a portion is open to adjust a size according to the size of a user's breast while wrapping and covering the user's breast, a thermal insulating material filled inside the cover, and a length adjustment unit provided in the open portion of the cover to connect both sides of the open cover, and adjusting the size of the cover.