The kidney and hypertension in pregnancy: twenty exciting years

Before 1980 research on the kidney and hypertension during pregnancy was neglected, although these diseases, especially hypertension, are major causes of morbidity to mother and child. The past 20 years, however, has witnessed a striking reversal of this neglect. This review focuses on recent progress in renal physiology, kidney disease, and hypertension as relates to pregnancy. Why do renal hemodynamics increase markedly in pregnancy? Studies have suggested roles for nitric oxide synthase, prostaglandins, endothelin and relaxin. This area of research is exciting, as unraveling why glomerular filtration rate and renal plasma flow increase in pregnancy may eventually help all patients with acute and chronic renal function loss. Concerning other advances: Micropuncture studies in rats, and the interpretation of fractional dextran clearances in humans show that the hyperfiltration that occurs during normal gestation is not associated with increased glomerular capillary pressure. Finally, description of changes in osmoregulation and in the metabolic disposal of arginine vasopressin in human pregnancy led to identification and appropriate treatment of a new group of disorders termed "transient diabetes insipidus of pregnancy." Chronic renal disease of any severity once led to proscription or interrupting of pregnancy. Clinical-pathological correlation studies and long-term follow-up of the mothers have revealed that most of these gestations succeed with little risk of worsening the natural history of the kidney disorder. This is also true in allograft recipients, and we now have guidelines to counsel both groups of patients. Progress relating to hypertension in pregnancy has been in 2 broad areas; systematic attempts to accurately define and differentiate the various disorders and population studies to predict, prevent, and improve the management of preeclampsia. There has also been considerable progress in unraveling the pathophysiology and identifying the cause of preeclampsia.