Pathophysiology of venous insufficiency during pregnancy.

Pregnancy is a risk factor for venous insufficiency. Up to 30 percent of women will develop venous insufficiency during their first pregnancy, and with each next pregnancy its prevalence is higher. Several pathophysiologic mechanisms are involved in the pathophysiology of venous insufficiency during pregnancy. The role of these mechanisms in the pathophysiology of venous insufficiency during pregnancy is still a point of discussion. Mechanical compression of enlarged uterus on pelvic veins was the first considered responsible for the occurrence of venous insufficiency during pregnancy. Soon, it was found that hormonal changes in pregnancy cause reduction in venous tone, and this reduction was postulated to be a major factor in pathophysiology of venous insufficiency. In a large number of subsequent studies both hypotheses were tested, being confirmed or rejected, but no consensus has been reached. This paper reviews current knowledge regarding pathophysiology of venous insufficiency during pregnancy, and discusses the possible role that some as yet uninvestigated mechanisms might have in it.