Hypertension in pregnancy: definitions, familial factor, and remote prognosis.

The clinical diagnosis of preeclampsia is often erroneous, for it may be confused with latent hypertension, acute or chronic renal disease, or frank essential hypertension that had abated during much of pregnancy. Eclampsia and "true" preeclampsia run in families with a frequency suggesting that a single recessive gene may be responsible. Eclampsia and "true" preeclampsia do not cause chronic hypertension, whatever their durations. Gestational hypertension is merely hypertension without proteinuria or abnormal edema. It often has been the basis for the diagnosis of mild preeclampsia, although renal biopsy samples almost never show the characteristic lesion in the absence of proteinuria. Gestational hypertension is often a sign of latent hypertension unmasked by pregnancy. Women with gestational hypertension ultimately have a high prevalence of chronic hypertension, whereas all those whose pregnancies are normotensive ultimately have a low prevalence.