Various rheological properties of blood were investigated in pregnant and non-pregnant women of similar age. The results from 27 women with abnormal pregnancies were compared to those obtained from 17 non-pregnant women. In abnormal pregnancies we found a reduction of the erythrocyte filtration and a pathological use in red cell aggregation and in the shear resistance of the aggregates. Fractional light transmission (T7/T0) was higher than 1.0, suggesting that pressure gradients in the capillary circulation are not sufficient to disperse red cell aggregates. Thus, rheological factors may be partly responsible for the clinical consequences of pre-eclampsia. Pathological red blood cell aggregation and stagnation are consequences of the changed flow properties in the microcirculation. Even a small decrease of the local pressure gradients in the microcirculation of patients with pre-eclampsia would impair the dispersal of red blood cells and lead to their increased aggregation. Complete occlusion of the placental circulation by these aggregates would impair oxygen transfer at a speed that has been calculated from a diffusion equation based on the concept of the placenta as a hollow cylinder.

Adult↗

PubMed1979

[Comparative examinations of high-molecular maternal serum protein bodies during pregnancy--a contribution to biochemical pregnancy control (author's transl)].

The maternal Serum concentrations of beta 1 SP 1, IgM and alpha 2-macroglobulin were determined in relation to the gestation age, using the simple radial immunodiffusion method in 102 non-pathologic pregnancies and 35 pregnancies involving risk factors. To assess the clinical relevance of these determinations, we examined to what extent the changes in concentration of beta 1 SP 1 IgM and alpha 2-macroglobulin would permit a prognostically useful conclusion on the placenta function and foetal condition. All patients with lowered beta 1 SP 1-serum concentrations were examined for their antepartua CTG-evaluation, as well as the type of termination of parturition. The normal distribution for beta 1 SP 1 showed a continuous rise in serum concentration up to the 37th pregnancy week. During the last 3 weeks, beta 1 SP 1 remained almost constant. For the cases with EPH-gestosis and placenta insufficiency, a beta 1 SP 1-concentration below the normal distribution level was found in the large majority of all cases. In diabetes mellitus during gravidity, twin gravidity and MHN, the determination of beta 1 SP 1 is not of any decisive prognostic significance. The maternal serum levels of IgM showed no significant differences when comparing normal pregnancy and risk pregnancy. The serum concentration of alpha 2-macroglobulin increased in both groups of patients with increasing gestation age. Of the three examined protein bodies, we consider beta 1 SP 1 to be a good, additional parameter for the assessment of the trophoblast function.

Female↗

PubMed1978

[Erythrocyte alteration in long standing labor inhibition with a beta-sympathicomimetic drug (Partusisten) (author's transl)].

The relative flow rate of the red blood cells in a hematocrit of 10% was measured with a 5 mu nuclepore filter system. The influence of Partusisten was determined by the alteration of the red blood cells. The in vitro concentration of 0.1 ng Partusisten/ml blood resulted in a relative improvement of the flow rate, which we also found in normal pregnancies. However, in a vivo concentration of 4 microgram intravenous Partusisten/min for 48 h, the red cell alteration properties decreased. After a greater time interval, the red blood cells alteration was about the same as in the pre-drug level. The uteroplacental perfusion changed in dependence to the concentration of the beta-mimetic drug (Partusisten). The presence of rigid red blood cells can be first seen in the microcirculation impairment. Depending on the concentration of Partusisten, a protective effect on the flow properties of the red blood cells could be achieved, which altered during pregnancy. However, in late gestosis, a lower dosage should be administered than in labor inhibition.

Erythrocytes↗

PubMed1978

[The therapy of the hypertensive form of late gestosis (author's transl)].

Based on five cases of intrauterine death associated with preeclamptic toxemia, a possible relationship between the antihypertensive treatment with Catapres and the fatal outcome of the fetus is discussed. Catapres is known to decrease cardiac output and, in addition, diminishes the utero-placental circulation. For effective prevention of hemodynamic failure in such cases, it is advisable to use Catapres only in combination with adequate intravenous infusion therapy. Further investigations concerning this possible relationship should be done to determine sufficiently whether or not Catapres can be used without risk as a hypertensive drug in late gestosis.

Adult↗

PubMed1977

[Changes in the blood rheology and their influence on the oxygen diffusion in normal and pathological pregnancies (author's transl)].

Blood viscosity studies were carried out at regular intervals in 51 patients with normal pregnancy and in 27 patients with high risk pregnancy, i.e. with EPH-gestosis and placental insufficiency. During gestation the relative blood viscosity is significantly increased compared to 15 normal non-pregnant women. At a corrected hematocrit of 45% we found a direct correlation to plasma fibrinogen and to the blood sedimentation rate. Although the whole blood viscosity does not indicate any change in normal pregnant women, there is, however, a viscosity increase in the last trimester of high risk pregnancies. Additionally a mathematical model of the oxygen diffusion in the placental cotyledo demonstrates rapid decrease of the oxygen partial pressure in the maternal intervillous channel if the microcirculation of the "Placenton" is impaired.

Blood Sedimentation↗

PubMed1977

A reflection on the oxygen diffusion of the terminal villus of the human placenta (author's transl).

By using a simple model, transformed to cartesian coordinates, we examined the behavior of the fetal and maternal oxygen partial pressure on the terminal villus of the human placenta during a constant arteriovenous oxygen difference. For this purpose we divided the flow length of the cotyledon in central and a peripheral part. We found that the oxygen exchange takes place at a lower utero-umbilical oxygen pressure gradient it the reduction of the maternal blood flow velocity amounts to 30% of the normal value and if the diffusion distance is doubled. However under these circumstances a sufficient the oxygen supply of the fetal organism. This is the case with the total flow length of a single cotyledon, but some of the terminal villi in the periphery of the cotyledon, could receive at the same time a diminished oxygen supply leading to degenerative cell changes. At a progression of these morphological changes or during labor the oxygen transport can get insufficient.

Chorionic Villi↗

PubMed1977

[A simple filtration technique for the observation of the deformation of human erythrocytes during pregnancy (author's transl)].

A simple rheological test method, as developed by Reid and Dormandy, was applied. In a group of pregnant women (n = 25) without pathological conditions the filtrability of whole blood and of a 10% erythrocyte suspension was determined. The control is a group of healthy nonpregnant patients (n = 7) at different times of the ovulatory cycle. Compared with the control group the flow rate of whole blood in the pregnant state is decreased about 30%, whereas that of the erythrocyte suspension about 40%.

Erythrocytes↗

PubMed1977

[A mathematical model for the description of oxygen-diffusion in the intervillous space of the human placenta (author's transl)].

The oxygen consumption has a central place in the complicated interaction between diminished oxygen supply and degenerative trophoblastic tissue change. In the present investigation, that serves as a mathematical model, the problem of the diffusion equation for the constant state is discussed and solved. It is shown that the diminishing of length of the radius of the maternal blood compartment has the same meaning as the decrease in the flow velocity. The influence of the mass transfer coefficient h on the oxygen partial pressure and on the oxygen transfer is investigated. The influence of parameter variations on the placental alterations during toxemia is discussed and their clinical importance is obvious. Our theoretical model elusidates the value of an early therapeutical approach in the case of toxemia.

Blood Flow Velocity↗

PubMed1977

[Consideration of hemodynamics in the intervillous space of the placenta (author's transl)].

Using Freese's hemodynamic model, we calculated the speed and pressure distribution in the villi-free area of the cotyledon. The Navier-Stokes equation was converted approximately into Reynod factors. The villi-free area was described as circular diffusor. On the basis of our computations, we assume that a predominately laminar flow occurred in the intervillous space; we considered an angular apearature of between 10 and 40 degrees to be physiological. In this area, pressure distribution is homogenous. The model-theoretical considerations presented here substantiate Freese's conception.

Blood Flow Velocity↗

PubMed1971