Erythrocyte deformability of nonpregnant, pregnant, and fetal blood

Abstract

Erythrocyte deformability is an important determinant of microcirculation, of oxygen transport and release to the tissue. In an attempt to clarify the rheological peculiarity during pregnancy, erythrocyte deformability was measured in 10 nonpregnant controls and 10 pairs of mothers and newborns. When the hematocrit of the erythrocyte suspension in dextran solution was adjusted to 35%, the deformability of fetal erythrocytes was significantly higher than maternal blood (P < 0.05), and it was almost similar to that of nonpregnant controls. Erythrocyte deformability was dependent on the hematocrit, and there was an optimal hematocrit value at which the deformability was maximal. The hematocrit, where the deformability was maximal, was a lower value (32-35%) in maternal blood, conversely, a higher value (47-50%) in cord blood than that (40-43%) in the nonpregnant. Despite decreased deformability of maternal erythrocytes, it may be compensated by reducing the hematocrit (hemodilution), preserving effective peripheral circulation including uteroplacental perfusion. On the other hand, the deformability of fetal erythrocytes may be higher in vivo at the hematocrit of 47-50% to supply oxygen to the fetal tissue even in a low oxygen condition.

The influence of maternal erythrocyte deformability on fetal growth, gestational age and birthweight

“…On studying the factors contributing to blood flow in the intervillous space, we found that during the gestation period of greatest fetal growth (from weeks 20 to 30) there is an increase in the rigidity of the maternal erythrocytes [10,21,26,28] (table I), a risk factor contributing to reduced fetal growth, lower birthweight [21] and lower gestational age at birth, probably due to a diminution in maternal-fetal perfusion arising from an J. Perinat. Med.…”

“…Taking all this into account, during a normal term pregnancy the increase in erythrocyte rigidity cannot be attributed to increases in the size of the erythrocyte (MCV is invariable during gestation), to increases in MHCC (which after a decrease at the start of the gestation remained constant from week 20 until delivery) or to increases in intraerythrocyte viscosity (which fell, counterbalancing the increase in erythrocyte rigidity) (table I). This led us to speculate that the increased rigidity of the erythrocytes in the pregnant woman may be due to alterations in the fluidity or elasticity of the red blood cell membrane, induced by the pregnancy [1,10,28], which coincide with alterations in intracellular viscosity, in turn related to increases in LDL-cholesterol, phospholipids and blood atherogenic indices [31], influencing the fluidity and permeability of the erythrocyte membrane and fetal and placental size [30,45].…”

Three-dimensional refractive index tomograms and deformability of individual human red blood cells from cord blood of newborn infants and maternal blood

“…For example, different techniques have led to different interpretations of the deformability of cord RBCs. Previous work using light scattering or hemolysis techniques had reported that cord RBCs are more deformable than adult RBCs (9,10), whereas electron spin resonance and filtration studies had concluded that there are no significant differences in cell deformability between cord RBCs and adult RBCs (11)(12)(13).…”