The serum uric acid level varies during pregnancy. Based on the graph of this assay over time, the authors have distinguished three different ranges with very different foeto-maternal prognoses in hypertensive pregnant women. They conducted a retrospective study of 77 cases of hypertensive pregnant women with a total of 173 assays of the serum uric acid and a prospective study of 49 cases of normal pregnancies with 65 assays of the serum uric acid. The authors define a dangerous zone in which foeto-maternal complications were observed in 94 per cent of cases; a zone with a good prognosis in which complications were observed in only 2 per cent of cases; and an intermediate "warning" zone (covering one third of the assays), in which essentially foetal complications were observed in 32 per cent of cases. An interpretation of the serum uric acid in relation to the term of the pregnancy is therefore useful to determine the foeto-maternal prognosis in the majority of cases and constitutes a valuable parameter for monitoring the pregnancy and for the adaptation of the treatment to the severity of the disease.