USE OF LOW-FREQUENCY ELECTRICAL-IMPEDANCE MEASUREMENTS TO DETERMINE PHOSPHOLIPID CONTENT IN AMNIOTIC-FLUID

In this report we propose a new method for an in vitro test of the foe tal lung maturity based on the measurement of the electrical conductiv ity of the overall amniotic fluid obtained from transabdominal amnioce ntesis, since this quantity can be linked to a first approximation in a very simple way to the phospholipid content. We have carried out mea surements of 85 different samples of amniotic fluid as a function of g estation weeks and we have observed a pronounced change of the electri cal conductivity that reflects the increase in the phospholipid concen tration occurring at the end of normal pregnancies. The method could b e further developed to obtain similar information on in vivo experimen ts by means of bioelectric impedance tomography, taking advantage of t he frequency dependence of the tissue electrical impedance.