After 37 weeks of pregnancy, the fetus does not grow, divided into physiological and pathological reasons. 1. Physiological reasons: 37 weeks of pregnancy after the fetus does not grow may be due to 37 weeks of pregnancy after the fetus is basically fixed, the growth space will not be very large, as long as the examination is in line with the normal gestational weeks is normal. It may also be caused by the measurement error after the fetus into the basin, generally do not need special treatment. 2. Pathological causes: the fetus does not grow after 37 weeks of pregnancy may also be caused by maternal diseases, fetal factors, placental factors, umbilical cord factors. (1) Maternal diseases: maternal diabetes, hypertension, severe anemia or insufficient nutritional intake may cause the fetus to stop growing, and should be treated after relevant examinations. (2) Fetal factors: the fetus suffers from chromosomal anomalies or congenital malformations, etc., can also lead to 37 weeks of pregnancy does not continue to develop. (3) Placental factor: Placental aging, placental abruption, placenta hypoplasia, etc., and the decrease of placental blood supply will also lead to the situation that the fetus will not continue to grow. (4) Umbilical cord factor: when the umbilical cord is knotted, twisted, or wrapped around the neck after 37 weeks of pregnancy, the nutritional supply will be affected, which will also lead to the phenomenon that the fetus will no longer increase in size. There are many clinical reasons why the fetus does not grow in the second trimester, and it is recommended to consult a doctor in time, under the guidance of the doctor in order to clarify the specific causes of the disease.