Objective: To compare the prevalence of maternal and fetal complicatio
ns in hypertensive Pregnant women (excluding chronic hypertension) wit
h and without proteinuria. Methods: A prospective study of hypertensiv
e pregnant women referred for physician care in a principal teaching h
ospital between 1987 and 1993: 740 pregnant women were diagnosed as ha
ving preeclampsia or gestational hypertension on the basis of (i) excl
usion of essential or secondary forms of hypertension in pregnancy, (i
i) hypertension arising after 20 weeks gestation and returning to norm
al blood pressure after delivery. Clinical management was by one physi
cian in conjunction with that patient's obstetrician, according to a u
niform departmental protocol. Proteinuria was defined as greater than
300 mg/day or persistently greater than or equal to 1 g/L (i.e., 2+) o
n dipstick testing if 24-h urine was unobtainable. Main Outcome Measur
es: Maternal complications were: thrombocytopenia, renal insufficiency
, liver disease, neurological abnormalities, and severe hypertension (
greater than or equal to 170/110 mm Hg). Fetal complications were: per
inatal mortality; small for gestational age. Birth weight was recorded
. Results: Only 17% had true proteinuria. Substantially more women wou
ld have had this diagnosis (inaccurately) if <1 g/L (2+) on dipstick t
esting alone was accepted. There was a higher prevalence of all matern
al complications, and perinatal mortality was higher and birth weight
lower in women with proteinuria. However, similar maternal complicatio
ns still occurred in 4% to 13% of women without proteinuria. Conclusio
ns: Proteinuria is associated with a greater prevalence of maternal an
d fetal complications of hypertensive pregnancy. However, the absence
of true proteinuria does not define a strictly benign subgroup as betw
een 4% and 13% of hypertensive women without true proteinuria will als
o develop these complications. The outlook for the fetus in nonprotein
uric women remains very good. Thus, nonproteinuric hypertensive pregna
nt patients should be managed with the same degree of vigilance as for
proteinuric women.