Renal Effects of Preeclampsia

Dramatic hemodynamic alterations occur during a normal, healthy pregnancy with the kidneys playing a major role to ensure that these adaptive changes occur properly. Therefore, it is not surprising that a significant number of women may develop new onset renal dysfunction or exacerbation of preexisting renal disease during pregnancy. Perhaps the most commonly encountered gestational disorder is hypertension, which can lead to significant complications for both the mother and the fetus when left untreated. A variety of factors may cause or contribute to the development or worsening of hypertension during pregnancy; nevertheless, clinically, hypertensive disorders of pregnancy can be divided into four major categories as recommended by the National High Blood Pressure Education Program Working Group on High Blood Pressure in Pregnancy: preeclampsia, chronic/preexisting hypertension, preeclampsia superimposed upon chronic hypertension, and gestational hypertension [1]. Of particular importance in defining these categories is the time of onset of hypertension during pregnancy, whether the women had preexisting hypertension prior to pregnancy, and whether proteinuria is present. Hypertension prior to pregnancy or occurring before 20 weeks of gestation indicates chronic/preexisting hypertension while hypertension occurring after 20 weeks of gestation but without proteinuria defines gestational hypertension. Preeclamspia is gestational hypertension with the additional feature of proteinuria. Of these hypertensive disorders of pregnancy, preeclampsia is the most common and can cause devastating systemic consequences including substantial renal injury. In this chapter, we discuss the pathologic manifestations and molecular pathologenesis of preeclampsia with a special emphasis on the renal effects of this disease.