The enlargement of a woman’s nose after pregnancy is caused by sodium retention in the body and increased breathing amplitude, which need to be analyzed specifically. 1. Water and sodium retention: After pregnancy, the level of progesterone in a woman’s body rises, which can easily cause water and sodium retention, which may lead to the enlargement of the nasal cavity, mucosal edema and other conditions, which are manifested in the enlargement of the nose after pregnancy. 2. Breathing amplitude becomes bigger: after pregnancy, especially in the second trimester, pregnant women are easy to be in a state of fatigue after activities, the respiratory rate will be faster, the respiratory amplitude will become bigger, and thus the nose will become bigger. When a woman’s nose becomes bigger after pregnancy, there is no need to worry. If it is accompanied by other uncomfortable symptoms, such as severe edema, breathing difficulties, etc., you need to go to the hospital in time, under the guidance of the doctor for standardized treatment.