[Diagnosis of pulmonary maturity in the fetus].

The various biochemical and biophysical methods to assess fetal lung maturity are reviewed. So far the most widely used biochemical method is the L/S ratio, but in complicated pregnancies mainly in diabetes mellitus, the determination of the lung profile (including PG) must be carried out to reduce false immature ratios. Biophysical methods, like foam stability tests and optical density, are easy and quick, but less precise.