The relation of angiotensin-converting enzyme to the pregnancy-induced hypertension-preeclampsia syndrome

Abstract

Angiotensin-converting enzyme, the polypeptide that converts angiotensin I to angiotensin II, was measured in the serum of 114 pregnant women who had normal blood pressure, pregnancy-induced hypertension-preeclampsia, and chronic hypertension with or without pregnancy-induced hypertension. Angiotensin-converting enzyme levels were unrelated to weeks of gestation. The angiotensin-converting enzyme levels were similar in normotensive women (21 .l f 6.9 units/ml), women with chronic hypertension without pregnancy-induced hypertension (23.1 -t 2.7 units/ml), and patients with pregnancyinduced hypertension where magnesium sulfate (22.6 & 6.7 units/ml) had been administered prior to angiotensin-converting enzyme assay, but these values were significantly less than those in patients with pregnancy-induced hypertension with no magnesium sulfate (29.1 f 6.5 units/ml) therapy and in women with chronic hypertension with superimposed pregnancy-induced hypertension (30.7 -e 4.4 units/ml) (p < 0.005). Maternal venous and umbilical venous and arterial angiotensin-converting enzyme levels were as follows: The maternal venous level was less than the cord venous level and greater than the cord arterial value. Neither neonatal size nor twin gestation influenced the angiotensin-converting enzyme levels. Patients with diabetes mellitus had variable angiotensin-converting enzyme values regardless of the status of the blood pressure. The physiologic theories of blood pressure control in pregnant women are discussed in relation to the renin-angiotensin, bradykinin, and prostaglandin systems, (AM J OBSTET GYNECOL~ 986; 154:792-800.)