Fetal tremors can be fetal movements or fetal hiccups etc. 1. Fetal movement: It is caused by the movement of the fetus in the uterus touching the uterine wall. The number of fetal movements is not regular and the duration of fetal movements is relatively short. Normal fetal movement is 3-5 times per hour on average. If the fetal movement is too frequent or too little, you need to go to the hospital in time to rule out the possibility of intrauterine hypoxia. 2. Hiccups: fetal hiccups are caused by fetal diaphragm contraction, the fetus through the continuous inhalation of amniotic fluid, stimulate diaphragmatic spasm through hiccups to promote lung maturation. Fetal hiccups are more regular, as if the heartbeat, usually lasts a few minutes, is a normal physiological phenomenon. Fetal hiccups are a normal physiological phenomenon. Fetal hiccups need to be diagnosed in the hospital in a timely manner, and any abnormality needs to be corrected in time to avoid affecting the healthy development of the fetus.