Renal biopsy in pregnancy-induced hypertension

Percutaneous renal biopsy, introduced 20 years ago, has revolutionized our understanding of many diseases affecting the kidney. In studies performed in nonpregnant subjects substantial progress in defining the mechanism, prognosis and treatment of a host of renal diseases was achieved by correlating clinical findings and renal function with light, electron and immunofluorescent microscopy. In the early 1960's investigators described the renal lesions associated with preeclampsia and made initial clinicopathological correlations, but relatively few studies combining light, electron and immunofluorescent findings in pregnant women have appeared to date. This is because clinical circumstances rarely justify even the minimal risks of biopsy during gestation, and after the disease has regressed, nephrology consultation is not requested in the puerperium. In addition, a report of excessive bleeding and other complications in gravidas, although not encountered by other groups (and personal experience of the authors), has contributed to the lack of enthusiasm for renal biopsy on obstetrical services and to the belief that this procedure is not advisable both during gestation and the immediate puerperium. This article reviews the renal morphology of preeclampsia and described those aspects of it in which current knowledge is still incomplete. Indications, benefits, and risks of kidney biopsy during pregnancy or puerperium will be discussed, with emphasis on the prognostic information to be expected from the procedure which may help in predicting the outcome of future pregnancies.