Venous distensibility during pregnancy. Comparisons between normal pregnancy and preeclampsia.

Preeclampsia is associated with increased peripheral resistance. This study was performed to determine whether an increase of venous distensibility occurs as well in preeclampsia. We obtained venous distensibility by measuring the venous pressure-volume relation in the forearm with a water-filled plethysmograph. Twenty-one women with normal pregnancy, 12 women with severe preeclampsia, and 8 women with mild preeclampsia were studied during the third trimester and/or 6 weeks after the delivery. Ten nonpregnant normotensive women were also studied. Venous distensibility was greater (P < .01) in normal pregnant women and smaller (P < .01) in women with preeclampsia during pregnancy than postpartum. The magnitude of the decrease of venous distensibility correlated with the severity of preeclampsia. Venous distensibility was similar between normotensive nonpregnant women, women with normal pregnancy during the postpartum period, and women with preeclampsia during the postpartum period. Thus, venous distensibility increased during normal pregnancy. In preeclampsia, the decrease of venous distensibility occurred during pregnancy but was reversed postpartum. These results may suggest that a decrease of venous distensibility occurs during preeclampsia. These venous abnormalities may contribute to impaired control of hemodynamics in preeclampsia during pregnancy.