The assessment of fetal behavior in early pregnancy: comparison between 2D and 4D sonographic scanning

To determine the accuracy of 4D sonography in the assessment of embryonic and early fetal motor activity in the first trimester of normal pregnancy, in comparison to the 2D sonography.

Fifty pregnant women between 6-14 weeks of gestation with singleton pregnancy were assigned for the investigation. Two dimensional and four dimensional recordings were displayed on the screen and recorded on the videotape during the 15 minutes observation period.

General body, head and limb movements recorded by 2D sonography were notable by 4D technique in the same gestational age. These movements were presented collectively with maximum, minimum, and median frequencies during 15 minutes observation period. Spearman rank order correlation reached statistical significance (P<0.05) between the frequencies of all observed movement patterns assessed by two different techniques. Several movement patterns, such as sideway bending, hiccup, breathing movements, mouth opening and facial movements could be observed only by 2D sonographic technique in this period of gestation.

Presently, both 2D and 4D methods are required for the assessment of early fetal motor development and motor behavior. It is reasonable to expect that such technological improvement may provide some new information about the intrauterine motor activity and facilitate the prenatal detection of some neurological disorders.