Studies in normal pregnancy. I. Serum lipids and fatty acid composition of serum phosphoglycerides.

Elevated serum lipids in normal pregnancy have been confirmed by the present study. In normal pregnancy the relative fatty acid composition of serum lecithin was characteristically high in palmitic acid (15:0). From the present knowledge of lipid metabolism in pregnancy there is no obvious explanation for this finding. Furthermore, the serum lecithin relative fatty acid composition mirrored a possible dietary influence with a decrease in the essential fatty acid, linoleic (18:2) and arachidonic (20:4) acids and of the sum of the fatty acid of the linoleic acid series (n-6). This expression for a relative deficiency in essential fatty acids might be due to changes in dietary habits during pregnancy, e.g. an increase in particularly refined carbohydrates. Reciprocal changes in oleic (18:1) and linoleic (18:2) acids further support this suggestion. An expected increase in serum lecithin containing arachidonic acid (20:4)-due to estrogen influence on liver lecithin synthesis-could not be verified in week 34 of the normal pregnancy.