Active and Inactive Renin Throughout High Risk Pregnancy

Abstract

Women with history of pregnancy induced hypertension (PIH) and/or unexplained foetal loss have a greater prevalence of high risk pregnancy. Since recent studies suggest that changes in the activity of the renin system may be important in complicated pregnancy, we have determined active (AR) and inactive (IR) renin (by enzymatic method, ng/ml/h) in 36 women (age 30.7 ± 5.7) with history of PIH or foetal loss. Blood samples were collected monthly throughout pregnancy. Ten patients (pts) showed a significant fall in active renin (<= 50%) 4±1 week before foetal distress was detected. In 3 of these pts foetal death was present and associated to significantly lowered values of inactive renin. No significant correlations with the onset of arterial hypertension, proteinuria, plasma uric acid, plasma creatinine and sodium excretion were observed. In conclusion active renin and inactive renin are partly dissociated in their behaviour throughout pregnancy; however it appears that a decline in both may represent an early sign of foetal distress but not of PIH.