Detection frequency by thin-layer chromatography of phosphatidylglycerol in amniotic fluid with clinically functional pulmonary surfactant.

Densitometric lecithin/sphingomyelin ratios (LSR) and the presence of phosphatidylglycerol (PG) were determined for 735 consecutively received amniotic fluids. Of the 371 fluids with "mature" LSR between 2.0 and 4.5, more than one-third lacked detectable PG. Clinical outcomes for the 305 of the total group that were delivered within 72 h of sampling were also determined. Respiratory distress syndrome (RDS) did not occur in the 239 cases with LSR greater than or equal to 2.0, even when, as in 43 instances, PG was not detected. When the LSR was greater than or equal to 2.0, transient tachypnea was more prevalent in the absence of detectable PG (PG detected, 3% transient tachypnea; PG undetected, 16% transient tachypnea). Of the 103 cases where PG was undetected, 58% exhibited no respiratory problems. Even in the 60 cases where the LSR was less than 2.0 and PG was not detected, 42% of the cases were free of respiratory problems. RDS did not occur in any case where PG was detected, even in the six where the LSR was less than 2.0. We evaluate these results in light of various contradictory reports in the literature.