Under normal circumstances, it is difficult to see all the limbs by color Doppler ultrasound at 32 weeks.

Because although the limbs grow up in the third trimester of pregnancy, it is easier to see, but because the fetus is enlarged and the bones are calcified, if the fetal position is lateral, the side away from the probe can not be seen clearly. In addition, due to the uterine gap, the limbs are rarely fully extended and it is not easy to see.

Therefore, the examination of fetal limbs is generally done at 18 ~ 24 weeks.