Influence of pregnancy on the fatty acid composition of plasma phosphatidylcholine and on plasma choline concentrations in humans.

Abstract

Dietary choline is used for hepatic synthesis of phosphatidylcholine (PtdCho) and spingomyelin (SM). Along with betaine, choline also serves as a methyl donor. We collected fasting blood samples at trimester 1 (11–15 weeks gestation), trimester 2 (19–23 weeks gestation) and trimester 3(34–37 weeks gestation) to assay the plasma concentration of these four compounds and fatty acid composition of PtdCho. Of the 15 women recruited, 12 had normal pregnancies. While plasma PtdCho concentrations increased significantly (P<0.05) from trimester 1 to 2 and maintained through to trimester 3, plasma choline concentrations increased gradually attaining significance (P < 0.001) during trimester 3. Betaine and spingomyelin concentrations significantly decreased late gestation. The plasma PtdCho fatty acid species derived from phosphatidyl ethanolamine methyl transferase (PEMT) activity, showed the most interesting changes; while 20:4 and 18:2 concentrations remained the same through pregnancy, 18:0 decreased in early gestation with no further depletion in late gestation. Multi-regression analysis showed that 18:0 and 20:4 were strong predictors of plasma choline concentrations (R2 =0.89; P<0.001) in trimester 3. Therefore during late gestation, PEMT pathway makes a greater contribution to plasma PtdCho composition. This spares the dietary supply of choline and therefore supports plasma choline increases.