Plasma uric acid remains a marker of poor outcome in hypertensive pregnancy: a retrospective cohort study

Abstract

Objective: To examine the relationship between hyperuricaemia, haemoconcentration and maternal and fetal outcomes in hypertensive pregnancies.

Design: Retrospective analysis of a database of hypertensive pregnancies.

Setting: St George Hospital, a major obstetric unit in Australia.

Population: A cohort of 1880 pregnant women without underlying hypertension or renal disease, referred for management of pre-eclampsia or gestational hypertension.

Methods: Demographic, clinical and biochemical data at time of referral and delivery were collected for each pregnancy. Women were grouped according to diagnosis (pre-eclampsia or gestational hypertension) and logistic regression analysis was used to determine the relationship between uric acid, haemoglobin, haematocrit and adverse outcomes; an α level of P < 0.01 was used for statistical significance.

Main outcome measures: Composites of adverse maternal and fetal outcomes.

Results: In women with 'benign' GH (without proteinuria or any other maternal clinical feature of pre-eclampsia) gestation-corrected hyperuricaemia was associated with increased risk of a small-for-gestational-age infant (OR 2.5; 95% CI 1.3-4.8) and prematurity (OR 3.2; 95% CI 1.4-7.2), but not with adverse maternal outcome. In the whole cohort of hypertensive pregnant women (those with pre-eclampsia or gestational hypertension) the risk of adverse maternal outcome (OR 2.0; 95% CI 1.6-2.4) and adverse fetal outcome (OR 1.8; 95% CI 1.5-2.1) increased with increasing concentration of uric acid. Hyperuricaemia corrected for gestation provided additional strength to these associations. Haemoglobin and haematocrit were not associated with adverse pregnancy outcome.

Conclusions: Hyperuricaemia in hypertensive pregnancy remains an important finding because it identifies women at increased risk of adverse maternal and particularly fetal outcome; the latter, even in women with gestational hypertension without any other feature of pre-eclampsia.