Comparison of the peripartum and postpartum phospholipid polyunsaturated fatty acid profiles of lactating and nonlactating women

Background: Pregnancy is associated with increased absolute amounts of doco sahexaenoic acid (DHA; 22:6n-3) in plasma phospholipids. Expressed as a pro portion of total fatty acids, DHA declines slightly in late pregnancy but l ittle information is available on the normalization of DHA postpartum, whic h may be different in lactating and nonlactating women. Objective: The aim was to investigate maternal plasma and erythrocyte long- chain polyunsaturated fatty acids (long-chain polyenes; LCPs) postpartum, p articularly DHA, in relation to lactation and dietary LCP intake. Design: Healthy pregnant women who intended to breast-feed or exclusively b ottle-feed their infants were studied at 36-37 wk of pregnancy. Blood sampl es were collected at entry, after parturition on days 2 and 5, and 1, 2, 4, 8, 16, 32, and 64 wk postpartum. Fatty acid profiles were analyzed in plas ma and erythrocyte phospholipids. Dietary intakes were assessed 4 and 32 wk postpartum with a validated food-frequency questionnaire. Results: After delivery, the percentages of plasma linoleic, arachidonic, e icosapentaenoic, and docosapentaenoic acids increased over time, whereas th e percentage of docosapentaenoic acid decreased; the patterns of change did not differ significantly between the lactating and nonlactating groups. Th e percentage of DHA in plasma and erythrocyte phospholipid fatty acids decl ined significantly in the 2 groups, more so in the lactating women, and was enhanced when the lactation period was extended. Despite the apparent high er dietary intake of essential fatty acids in the lactating group at week 4 , it was not significantly different from that of the nonlactating group. Conclusion: Normalization of maternal plasma and erythrocyte phospholipid n -3 LCPs differs significantly between lactating and nonlactating women post partum but that of n-6 LCPs does not.