Amniotic fluid squalene and fetal maturity.

Gas chromatographic profiles of neutral lipids in amniotic fluid pellets were analysed for 51 specimens collected from patients in the last two months of pregnancy. The most noticeable change was a large increase in squalene relative to other components in samples at term. By expressing data as a ratio of squalene to cholesterol (S/C), it was possible to accurately predict which amniotic fluid specimens came from patients whose pregnancies were of a gestation of 40 weeks or later. Highest values for S/C and for squalene were obtained for pregnancies which were several weeks overdue.