[Hemorrheological characteristics of fetal blood drawn in utero from the cord].

Extensive studies of hemorheology of cord blood (drawn just after delivery) have evidentiated a peculiar rheological pattern: less filterable red cells, reduced erythrocyte aggregation, lowered plasma viscosity. This pattern has been suggested to be important for maintaining a sufficient O2 supply to fetal tissues, by avoiding hyperviscosity despite increased RBC rigidity. However, cord blood at birth is not exactly fetal blood and we are not yet aware of studies of fetal blood drawn in utero several weeks before delivery.

[Hemorrheological parameters during normal labor and uterine contraction].

Considering the modified fluidity of blood during numerous kind of stress, the authors studied blood rheology during delivery as an example of a particularly severe stress. The authors measured blood and plasma viscosity and erythrocyte aggregation in 77 pregnant at the following stages of delivery: below 4 cm dilatation; more than 4 cm dilatation; during fetus expulsion, during after birth delivery. Apparent blood viscosity and viscosity adjusted to 45% hematocrit rose to reach a peak during expulsion (p less than 0.