Fetus is more active at night, which is mostly related to factors such as strong secretion of maternal hormones and quiet environment at night. 1. Exuberant secretion of maternal hormones: the secretion of hormones in the mother’s body is usually more vigorous at night, resulting in the fetus being active at night. 2. Quiet environment at night: Because pregnant women are more active during the day, their attention is more distracted, so they may not pay too much attention to the activities of the fetus; while the environment is very quiet at night, the pregnant women themselves are less active and more focused, and may obviously feel the fetal movement in the uterine cavity, so they feel that the fetus is more active at night. More active fetal movement at night is generally normal, but if there is frequent fetal movement followed by a decrease in fetal movement, we must pay attention to it, which is often the first manifestation of intrauterine oxygen deprivation of the fetus, and we recommend timely medical attention.