Simultaneous assessment of fetal lung maturity and sebaceous gland function by gas chromatography

Lipid profiles were analysed by gas chromatography of underivatised extracts from pellets and supernatant fractions of amniotic fluid (AFP and AFS). Peaks, identified as diglycerides resulting from on column decomposition of phosphoglycerides at high temperature, were obvious in gas chromatograms of AFS. The C₃₂ diglyceride, mainly derived from dipalmityl lecithin, was not a prominent peak in AFS from pregnancies from which babies subsequently developed respiratory distress syndrome. There was evidence of a moderate increase of squalene in AFS and AFP for 10 pregnancies of 36–38 weeks gestation resulting in the birth of small for gestational age babies. The increase was not obvious for 21 out of 22 control pregnancies delivering appropriate for gestational age babies. This demonstrated that we had an assessment of two fetal functions in one chromatographic run, the ratio of C₃₂/C₃₄ diglycerides providing a measure of lung maturity and squalene providing an index of proximity to term or of the presence of intrauterine growth retardation.