HYPERTENSION IN PREGNANCY - THE INCIDENCE OF UNDERLYING RENAL-DISEASEAND ESSENTIAL-HYPERTENSION

The objective of this study was to ascertain the likelihood of underly ing renal disease or essential hypertension in women diagnosed antepar tum as having pre-eclampsia. One hundred eighty-six women (antepartum diagnosis of pre-eclampsia in 87 women and gestational hypertension, a lso known as ''mild pre-eclampsia'' by other definitions, in 99 women) in whom no underlying disorder was apparent during pregnancy or the e arly puerperium were entered into the study. Women were reviewed betwe en 3 and 60 months postpartum. All patients were assessed by measureme nt of blood pressure, urinalysis, and phase-contrast urine microscopy, and those with pre-eclampsia also had plasma urea, electrolyte, and c reatinine concentrations determined and underwent renal imaging with e ither intravenous pyelography or ultrasound. The kidneys were also ima ged in the gestational hypertension group if there was any clinical su spicion of underlying renal disease on review. Essential hypertension was diagnosed if systolic blood pressure was higher than 140 mm Hg and /or diastolic blood pressure was higher than 90 mm Hg after 3 months p ostpartum and the results of other investigations were normal. Renal d isease was diagnosed in the presence of abnormal findings on urinalysi s, urine microscopy, or renal imaging, or by elevated plasma creatinin e concentration. Seven (8%) of the 87 women with pre-eclampsia had und erlying disease (essential hypertension, five patients; renal disease, two patients [one with reflux nephropathy and one with medullary spon ge kidney]), as did 16 (16%) of the 99 women with gestational hyperten sion (essential hypertension, 14 patients (14%); renal disease, two pa tients (2%) [one with medullary sponge kidney and one with thin baseme nt membrane disease]). Thus, approximately 10% of women with de novo h ypertension in pregnancy, in whom no underlying disorder is apparent d uring pregnancy or the immediate puerperium, will be found subsequentl y to have essential hypertension. Underlying renal disease is uncommon . (C) 1994 by the National Kidney Foundation, Inc.