Pregnant women who are unhappy for a short period of time have no significant effect on the fetus. If they are unhappy for a long period of time, it may affect the development of the fetus and lead to poor fetal development. During pregnancy, pregnant women are advised to maintain a good mood, which is beneficial to their health and the development of the fetus. If a pregnant woman is stimulated and unhappy in a short period of time, there is no obvious effect on the fetus, but if a pregnant woman is unhappy for a long period of time, it will lead to a decrease in the efficiency of the body’s metabolism, which is not conducive to good health and may affect the normal development of the fetus. Therefore, women should keep their mood happy during pregnancy, promptly eliminate bad emotions, properly cultivate hobbies and interests, promote physical and mental health, and pay attention to timely hospitalization when discomfort occurs.