Decreased prostacyclin biosynthesis preceding the clinical manifestation of pregnancy-induced hypertension.

Patients who develop pregnancy-induced hypertension exhibit a lesser increment in prostacyclin biosynthesis than healthy pregnant subjects. Whether this precedes the development of clinical disease and therefore may be important in the pathogenesis of pregnancy-induced hypertension or is a secondary event is unknown. We prospectively determined prostacyclin biosynthesis in pregnant subjects at risk of developing pregnancy-induced hypertension by use of noninvasive approach, measurement of the urinary metabolite 2,3-dinor-6-keto-prostaglandin F1 alpha. Patients were recruited at less than 20 weeks gestation. After delivery, patients were retrospectively allocated by use of preset criteria, to one of four groups: pregnancy-induced hypertension (n = 12), hypertension in labor (n = 22), chronic hypertension (n = 9), and normotension (n = 24). There was a significant increase in prostacyclin biosynthesis in all study groups during gestation. However, patients who developed pregnancy-induced hypertension exhibited a lesser increment and this difference persisted throughout gestation. These results are consistent with a pathophysiologic role for altered prostacyclin biosynthesis in women with pregnancy-induced hypertension. In addition, decreased prostacyclin formation identifies a population at risk of developing pregnancy-induced hypertension. Such information would assist the design of clinical trials of drugs, such as aspirin, that might prevent the development of this disease.