During the first trimester, the pregnant woman’s body undergoes a series of adaptive changes and comfortable and healthy clothing is a must during pregnancy. Therefore, wearing tight pants in the early stages of pregnancy is not recommended. In the early stage of pregnancy, the development of embryo needs good blood supply, so good blood supply is the basis to ensure the development of embryo. If you wear tight pants in the early stage of pregnancy, it will cause impaired blood circulation in both lower limbs, thus causing poor blood supply to the embryo, and in serious cases, the possibility of embryo maldevelopment and miscarriage. Secondly, wearing tight pants at the beginning of pregnancy will limit the increase in abdominal volume. During pregnancy, as the embryo develops, the uterus gradually increases in size and sufficient space is essential for the development of the embryo. Wearing tight pants will cause restrictions on the development of the embryo, and in serious cases, it may cause abnormal development of the embryo in the uterus and miscarriage. Finally, wearing tight pants can also restrict the daily activities of pregnant women. Moreover, tight pants are not ventilated, and women are more likely to suffer from vulvovaginal inflammation when they are pregnant. Wearing tight pants increases the chances of vulvovaginal inflammation even more. Therefore, it is recommended that pregnant women wear loose, comfortable pants and keep their perineum ventilated and dry during pregnancy. Wearing tight pants is not recommended.