[The effect of low blood pressure on venous function during and outside of pregnancy and therapeutic consequences].

Orthostatic dysregulations occur ten times more frequently in gravidae with low blood pressure than in those in whom it is normal. This condition can result in a temporarily insufficient blood supply to the uterus and hence to the foetus. As a consequence, abortions, premature and abnormal births, and complications during labour and lying-in occur more frequently among hypotonic women. Pathophysiologically, orthostatic dysregulations are caused by large quantities of blood remaining in the peripheral veins. In this connection it is well known that the hormonal change-over during pregnancy reduces venous tone, thus causing venous return to the heart to deteriorate. It has not yet been investigated whether or respectively how low blood pressure in pregnant and non-pregnant women affects venous hemodynamics and what effect treatment with dihydroergotamine (DHE) has. In order to answer these questions the authors performed 240 venous function measurements in a total of 140 pregnant and non-pregnant, hypotonic and normotonic women. Using a simple, non-invasive photoplethysmographic method, light reflection rheography (LRR), a check was first made as to whether there are differences in venous pumping in non-pregnant hypotonic as opposed to normotonic women. In 20 normotonic subjects the delta R mean value for venous drainage was 165 mV, while in 20 hypotonic women it was only 114 mV (p less than 0.001). While, on the basis of a corresponding classification, all of the normotonic women were classified as having normal veins or merely slight venous insufficiency, 14 hypotonic women were found to have moderately severe or severe venous insufficiency (p less than 0.0001).(ABSTRACT TRUNCATED AT 250 WORDS)