Free floating particles in Liqor amnii

This was a 38 week old pregnancy showing multiple echogenic particles in the amniotic fluid (liqor amnii) on ultrasound/ Color Doppler imaging. Such freely mobile particles in the amniotic fluid are called free floating particles and are commonly seen in the 3rd trimester. Sometimes, particulate debris, when abundant, can be confused with normal umbilical cord floating in the amniotic fluid, on grey scale B-mode ultrasound. However, Color Doppler easily distinguishes between the two (see Doppler images above). Studies show some direct correlation between the size and number of free floating particles and levels of Maternal serum alpha feto-protein (MSAFP). These particles are presumed to be the result of vernix caseosa shed from the fetal skin. However, free floating particles may be visualized on ultrasound imaging even during the 2nd trimester (when vernix is not present).