[Edema in pregnancy. Calculation of the contents of maternal cells]

In 1963 F.D. Moore and his colleagues described "the body cell mass", but up till now there has not been a practical method to isolate other components of the body. Electrical body impedance measurement makes it possible in pregnant women not only to separate the values relating to maternal tissues from those relating to fetal tissues but it is also possible to make out in the Lean Mass of the mother those parts that are due to extra-cellular fluid in the supporting tissues and particularly those that come from the cytoplasmic mass (water, proteins, electrolytes and dissolved substances). The method, which is founded on a well-known scientific basis, is simple and almost a-traumatic. It consists in measuring the electrical resistance given to the passage of a weak alternating current that is passed through two electrodes, one of which is placed on one hand and the other on the foot of the other side. This method gives a result in units of electricity (ohms) of the value of the active cellular component of the mother. As we know that the normal values are closely linked to the morphological features of the woman which are fixed, it is easy to determine them and compare the measurement obtained by impedance at the time the measurements are being taken. We therefore obtain an index N which is normally equal to 1 +/- 0.10 which gives evidence of an excess of cellular content when Nis greater than 1.10 or a decrease if N is less than 0.90.(ABSTRACT TRUNCATED AT 250 WORDS)