Total phospholipid choline concentration of amniotic fluid in the assessment of foetal gestational and lung maturity. I. Establishment of a direct enzymic method.

An enzymic assay of the choline-containing phospholipids of amniotic fluid which does not require lipid solvent extraction has been developed. Lecithin and sphingomyelin are the dominant phospholipids in mature lung surfactant. The total phospholipid choline content of amniotic fluid, which represents the molar sum of lecithin and sphingomyelin, may be expected to correlate with foetal lung maturity. The merits of our new analytical method of determination of total phospholipid choline concentration in amniotic fluid are discussed.