Lipid content of amniotic fluid cells.

The lipid content of fetal cells was determined in 45 samples of human amniotic fluid. Free and total cholesterol were estimated using a gas chromatographic method, and glycerides were evaluated through the enzymatic assay of their glycerol content. The number of orange cells was estimated after staining with Nile Blue sulphate. The chemically measured lipid content appeared closely related to the number of orange cells. Total cholesterol and glycerides showed a sharp increase after the 37th week of pregnancy. These tests seem to assess fetal maturity successfully, providing a further useful aid in the management of high-risk pregnancies. The chemical determination of cell-associated lipids showed good accuracy and reliability and, when compared with the histochemical method, allowed a better evaluation of progressive lipid accumulation within the amniotic fluid cells.