To investigate the methodology and feasibility of an anatomic survey of fetal limbs in the first trimester.

In this study, 533 normal fetus and 6 fetal corpse without limb abnormalities form June 2011 to August 2012 underwent an anatomic survey on the limbs in our consultation center. The limbs were scanned using a systematic continuous sequence approach: (1) Displaying upper arm and humerus, forearms and radius/ulna, hands in proximal to distal direction. (2) The thigh and femur, crus and tibia/fibula, feet was attempted from the sagittal section of each structure. (3) If the whole limb couldn′t be visualized in a section then the three segments will be demonstrated respectively. The position and movement also should be observed during the scan. Data were collected regarding gestation age, examining time and the structures.

The limbs except toes of 533 normal fetus were clearly observed, which was completely unaffected by gestational age, with the mean time of scanning is 98.6±37.4 s (rang: 36-189 s). The structures (including upper arms and humerus, forearms ,radius and ulna, hands, thigh and femur, crus and tibia, fibula, feet) of fetal limbs were clearly observed on the 6 fetal corpse, but the ossification center of fingers were steadily visualized until 13 weeks and toes after 13 weeks.

Scanning fetal limbs in the first trimester were feasible by a systematic continuous sequence approach in a short period of time.