1. Interpretation of fetal B-ultrasound in 4 months of pregnancy. 4 months of pregnancy is an important period of fetal development. B-ultrasound examination at this time can understand the health status of the fetus. B-ultrasound images can show the head, limbs, trunk and other parts of the fetus, helping doctors determine whether there are deformities or abnormalities in the fetus. 2. Fetal head and brain. B-ultrasound examination at 4 months of pregnancy can clearly observe the fetal head and brain. At this time, the fetal head