Ultrasound at 35 weeks of gestation suggests that short fetal calves may be related to intrauterine fetal developmental delay, maternal malnutrition, genetic factors and so on. 1. Fetal intrauterine growth retardation: If the umbilical cord is too thin, the placenta has low maturity, and the fetal umbilical cord blood flow is low, it will lead to fetal intrauterine growth retardation. 2. Maternal malnutrition: If pregnant women do not supplement calcium in time, it will affect fetal bone development. Women during pregnancy can eat more food rich in calcium, vitamins and protein. 3 genetic factors: if the parents are relatively short in height, the fetal calves are likely to be short. Fetal length can be increased in the second trimester of pregnancy, even if the fetal calves are short, there is no need to be overly nervous, to rule out genetic factors, some pregnant women can be supplemented to correct the fetal calves are too short. It is recommended that pregnant women consult a medical professional if they have any discomfort.