Serum phospholipid fractions measured by two dimensional thin layer chromatography in normal pregnancy.

Serum phospholipid fractions were quantitated by two dimensional thin layer chromatography in 85 apparently normal pregnant women at different gestational period. Fifteen healthy non-pregnant women matched for age served as controls. Normal chromatogram showed eight spots of serum phospholipid viz., phosphatidic acid (PA, 3.9 +/- 0.5%), cardiolipin (C, 7.2 +/- 0.4%), phosphatidylethanolamine (PE, 10.6 +/- 1.1%), phosphatidylglycerol (PG, 3.2 +/- 0.6%), lecithin (L, 34.5 +/- 1.8%), sphingomyelin (S, 31.0 +/- 1.4%), lysolecithin (LL, 8.6 +/- 1.2%) and phosphalidylionositol (PI, 1.0 +/- 0.2%). Serum total phospholipid which increased with gestational age, being lowest at 6 wk (220.2 +/- 4.8 mg/dl) and highest at 38 wk (290.3 +/- 4.5 mg/dl), started declining at term (275.8 +/- 5.8 mg/dl) and returned to levels in normal nonpregnant women (214.1 +/- 4.7 mg/dl) at 4 wk after delivery (217.2 +/- 3.3 mg/dl). PG was absent in both the first and second trimester and first appeared between 31-32 wk, i.e., in the third trimester of pregnancy when the mean per cent of PG was 0.7 +/- 0.4 per cent. During the first trimester when the L/S ratio was less than 1.2 the PI level was low (0.8 +/- 0.2%). Parallel to the increase in the L/S ratio to 2.0, the content of PI increased to 2.6 +/- 0.4 per cent. PG first appeared (0.7 +/- 0.4%) and PI concomitantly decreased (2.1 +/- 0.3%) when the L/S ratio exceeded 2.0 at 31-32 wk. Sequential analysis of maternal serum phospholipid fractions may be used as an additional tool in predicting gestational age of normal growing pregnancy.