Background: Being devoid of both nuclei and mitochondria, mature human erythrocytes provide an opportunity to study membrane structure and function outwith the restrictions of genetic control. With its unique rapid increase in vascularisation, pregnancy is considered the most opportune period in which to investigate blood rheology.
Methods: Maternal and fetal (cord) bloods were retained at delivery from 32 (25 singleton and seven twin) normal pregnancies at two maternity hospitals in the Glasgow area over a nine month period. Erythrocyte fatty acid compositions were assessed by mass spectroscopy, and corresponding membrane deformabilities measured by ultrafiltration through a membrone of 5 [micro]m diameter pore size, to mimic placental microcirculation.
Results: Significant direct correlations (Spearman rank) were found between erythrocyte membrane omega-3 docosahexaenoic acid concentrations and corresponding deformabilities in maternal and cord blood from both singleton and twin pregnancies, whereas greater omega-6 arachidonic acid content was associated with increased maternal membrane rigidity. Membrane concentrations of omega-3 fatty acids only correlated strongly both within and between maternal and cord bloods. Mean cord erythrocyte docosahexaenoic acid concentration was higher than maternal in singletons but lower in twins. When maternal erythrocyte concentrations exceeded about 7% (of total fatty acids), resistance to erythrocyte flow was virtually eliminated.
Conclusions: It may be that a greater maternal intake of docosahexaenoic acid should be encouraged in some pregnancies for optimal tissue perfusion. Fetal demand for docosahexaenoic acid may not be entirely satisfied in multiple pregnancies.
During pregnancy, supply of nutrients to the fetus is dependent on maternal diet and metabolism. Nutritional deficiencies have been highlighted in vegetarian and vegan mothers, and multiple pregnancies place an additional strain on such provision. (1)
The causes of the major complications of pregnancy, namely pregnancy induced hypertension and pre-eclampsia, are not known. Their adverse vascular pathologies and decreasing incidence from northern to southern Europe may have a parallel in the epidemiology of cardiovascular disease and an association with consumption of fish rich in omega-3 fatty acids. (2-4)
Omega-3 (or n-3) long chain polyunsaturated fatty acids (LCPUFAs) have been shown to reduce the incidence of miscarriage in persistent antiphospholipid syndrome. (5) Amelioration of the condition by low dose aspirin therapy may indicate involvement of fatty acids in inducing antibody production, as salicylate inactivation of cyclo-oxygenases directly inhibits arachidonic acid (AA; C20:4 n-6) metabolism. (6)
In spite of several taskforce reports that have emphasised the maternal (and fetal) dietary need for LCPUFAs, rather than their essential fatty acid precursors, during pregnancy, (7 8) it is probably true that the implementation of their recommendations has not been universal. In terms of overall maternal fatty acid requirements it is likely that, as they can be synthesised de novo, neither saturated nor monounsaturated fatty acids will play a pivotal role in that regard. The dietary essential fatty acids, linoleic (C18:2 n-6) and [alpha]-linolenic (C 18:3 n-3) cannot be synthesised in humans and are parent molecules of the n-6 and n-3 series LCPUFAs, which are critical to the formation and function of all biological membranes. Deficiencies in n-6 LCPUFAs are...