At 30 weeks of pregnancy, the legs are not short if the femur of the fetus is 53mm long. The normal range of fetal femur length at 30 weeks of pregnancy is 57.7±4.7mm, so if the femur is 53mm long it is within the normal range. When a woman is 30 weeks pregnant, she is in the late stages of pregnancy, when the embryo has already been formed and is gradually growing, so you can’t judge the development of the fetus purely according to the length of the femur. It is necessary to take into account a number of indicators, such as the head circumference, abdominal circumference, biparietal diameter and so on. At around 30 weeks of pregnancy, an ultrasound is usually performed to determine the development of the fetus. The ultrasound will look for abnormalities in the kidneys, ureters, etc., the size of the fetus and the fertility of the heart, as well as amniotic fluid, umbilical cord blood flow, etc. The ultrasound should be performed under the supervision of a doctor. This should be done under the supervision of your doctor.