1. The significance of fetal B-ultrasound at 3 months of pregnancy: 3 months of pregnancy is an important period of fetal development. B-ultrasound examination at this time can observe the development of the fetus, including head circumference, abdominal circumference, limb length and other indicators. These indicators can reflect whether the fetus is developing normally and whether there are any abnormalities. At the same time, the fetal organ structure, such as the heart, brain, etc., can also be observed through B-ultrasound images.