The role of serum uric acid as a prognostic indicator of the severity of maternal and fetal complications in hypertensive pregnancies.

OBJECTIVE

To examine whether an elevated serum uric acid level in hypertensive pregnant women is a useful prognostic indicator of severe hypertension; hemolysis, elevated liver enzymes, low platelets (HELLP) syndrome; and small for gestational age (SGA) infants.

METHODS

A total of 459 women newly diagnosed with hypertension in pregnancy were categorized into "gestational hypertension" and "hypertension with proteinuria (preeclampsia)" groups. Their serum uric acid levels were correlated with the development of HELLP syndrome, severity of hypertension, and incidence of SGA newborns (< 10th percentile birth weight). HELLP syndrome was divided into 3 classes depending on the severity of the thrombocytopenia. Prior to this study, serum uric acid levels had been measured in a group of normotensive women. Mean and standard deviation of serum uric acid levels for each group were compared using analysis of variance and student t-tests, where necessary.

RESULTS

Significant elevation in serum uric acid levels over normotensive pregnant women (285 +/- 72 micromol/L) was observed in both the gestational hypertensive group (341 +/- 83 micromol/L) and the preeclamptic group (384 +/- 93 micromol/L) of women (p < 0.001 and p < 0.05 respectively). Serum uric acid levels were also significantly elevated (p < 0.001) in women with gestational hypertension with HELLP syndrome (382 +/- 78 micromol/L) compared to those without HELLP syndrome (330 +/- 80 micromol/L). Preeclamptic women with HELLP syndrome (412 +/- 99 micromol/L) also demonstrated elevated uric acid levels (p < 0.05) over those without HELLP syndrome (374 +/- 87 micromol/L). However, the level of uric acid did not predict the severity of HELLP syndrome. The presence of SGA infants in the gestational hypertensive group was not associated with increased uric acid levels.

CONCLUSION

Uric acid levels, although significantly elevated in women with gestational hypertension and preeclampsia as compared to normotensive pregnant women, are not good prognostic indicators of the severity of the maternal or fetal complications.