Hyperuricemia facilitates the prediction of maternal and perinatal adverse outcome in patients with severe/superimposed preeclampsia

The association between serum uric acid and low birth weight in advance maternal age women with hypertension: An observational study

In China, the implementation of 2-child policy since 2015 entitles increasing number of advanced maternal age. Recently, Chinese hypertensive disorders of pregnancy (HDP) in advanced-age women have attracted significant clinical and epidemiological research interest. Previous studies have shown an association between serum uric acid (SUA) levels and low birth weight (LBW) in children. Several studies have reported that advanced maternal age is a risk factor for many complications in pregnancy, including LBW. However, it remains unclear whether SUA affects LBW risk in advanced maternal age mothers with hypertensive diseases. The study was observational in nature. A total of 692 advanced maternal age with hypertension were enrolled in our study. A variety of demographic and vital sign data, laboratory test results, and pregnancy outcomes were collected. Children born with LBW served as the clinical endpoint. On admission, blood samples were taken, and women with advanced maternal ages were divided into 2 groups based on their SUA levels. In order to investigate the association between SUA and LBW, a logistic regression model was used. E-value analysis was used to determine the residual unmeasured confounding. The mean SUA level was increased in advanced maternal age patients with HDP. Of 692 newborns, 244 (35.26%) have LBW. With possible confounders adjusted, high SUA levels were independent risk factors for LBW (odds ratio [OR]2.88, 95% confidence intervals [CI]1.22-6.81), multivariate logistic regression analysis using SUA as a continuous variable recapitulated the pattern (OR 1.01, 95% CI 1.00-1.01). In addition, SUA levels in women with advanced maternal age and hypertension were linearly related to LBW incidence. According to this study, SUA levels in patients with advanced maternal age and HDP are associated with LBW incidence.

The association of hyperuricemia and maternal and fetal outcomes among pregnant women: a meta-analysis

OBJECTIVE

This meta-analysis aimed to investigate the relationship between hyperuricemia and maternal and neonatal complications in pregnant women.

METHODS

We searched PubMed, Embase, Web of Science, and the Cochrane Library from the databases' inception to August 12, 2022. We included studies that reported results on the association between hyperuricemia and maternal and fetal outcomes among pregnant women. Using the random-effects model, the pooled odds ratio (OR) with 95% confidence intervals (CIs) was calculated for each outcome analysis.

RESULTS

A total of 7 studies, including 8104 participants, were included. The pooled OR for pregnancy-induced hypertension (PIH) was 2.61 [0.26, 26.56] (z = 0.81, p = .4165; I² = 96.3%). The pooled OR for preterm birth was 2.52 [1.92, 3.30] (z = 6.64, p < .0001; I² = 0%). The pooled OR for low birth weight (LBW) was 3.44 [2.52, 4.70] (z = 7.77, p < .0001; I² = 0%). The pooled OR for small gestational age (SGA) was 1.81 [0.60, 5.46] (z = 1.06, p = .2912; I² = 88.6%).

CONCLUSION

Results of this meta-analysis indicate a positive relationship between hyperuricemia and PIH, preterm birth, LBW, and SGA in pregnant women.

Chronic hypertension and superimposed preeclampsia: screening and diagnosis

Superimposed preeclampsia complicates about 20% of pregnancies in women with chronic hypertension and is associated with increased maternal and perinatal morbidity compared with preeclampsia alone. Distinguishing superimposed preeclampsia from chronic hypertension can be challenging because, in chronic hypertension, the traditional criteria for the diagnosis of preeclampsia, hypertension, and significant proteinuria can often predate the pregnancy. Furthermore, the prevalence of superimposed preeclampsia is unlikely to be uniformly distributed across this high-risk group but is related to the severity of preexisting endothelial dysfunction. This has led to interest in identifying biomarkers that could help in screening and diagnosis of superimposed preeclampsia and in the stratification of risk in women with chronic hypertension. Elevated levels of uric acid and suppression of other renal biomarkers, such as the renin-angiotensin aldosterone system, have been demonstrated in women with superimposed preeclampsia but perform only modestly in its prediction. In addition, central to the pathogenesis of preeclampsia is a tendency toward an antiangiogenic state thought to be triggered by an impaired placenta and, ultimately, contributing to the endothelial dysfunction pathognomonic of the disease. In the general obstetrical population, angiogenic factors, such as soluble fms-like tyrosine kinase-1 and placental growth factor, have shown promise in the prediction of preeclampsia. However, soluble fms-like tyrosine kinase-1 and placental growth factor are impaired in women with chronic hypertension irrespective of whether they develop superimposed preeclampsia. Therefore, the differences in levels are less discriminatory in the prediction of superimposed preeclampsia compared with the general obstetrical population. Alternative biomarkers to the angiogenic and renal factors include those of endothelial dysfunction. A characteristic of both preeclampsia and chronic hypertension is an exaggerated systemic inflammatory response causing or augmenting endothelial dysfunction. Thus, proinflammatory mediators, such as tumor necrosis factor-α, interleukin-6, cell adhesion molecules, and endothelin, have been investigated for their role in the screening and diagnosis of superimposed preeclampsia in women with chronic hypertension. To date, the existing limited evidence suggests that the differences between those who develop superimposed preeclampsia and those who do not are, as with angiogenic factors, also modest and not clinically useful for the stratification of women with chronic hypertension. Finally, pro-B-type natriuretic peptide is regarded as a sensitive marker of early cardiac dysfunction that, in women with chronic hypertension, may predate the pregnancy. Thus, it has been proposed that pro-B-type natriuretic peptide could give insight as to the ability of women with chronic hypertension to adapt to the hemodynamic requirements of pregnancy and, subsequently, their risk of developing superimposed preeclampsia. Although higher levels of pro-B-type natriuretic peptide have been demonstrated in women with superimposed preeclampsia compared with those without, current evidence suggests that pro-B-type natriuretic peptide is not a predictor for the disease. The objectives of this review are to, first, discuss the current criteria for the diagnosis of superimposed preeclampsia and, second, to summarize the evidence for these potential biomarkers that may assist in the diagnosis of superimposed preeclampsia.

Development and Validation of a Nomogram for Predicting the Risk of Pregnancy-Induced Hypertension: A Retrospective Cohort Study

Objective: To develop and validate a prediction model for identifying pregnant women at risk of developing pregnancy-induced hypertension (PIH) to guide treatment decision and classification of management. Methods: This study retrospectively enrolled 907 consecutive pregnant women with de novo hypertension from the Antenatal Care Center of Henan Provincial People's Hospital between June 1, 2018 and May 31, 2019. The cohort was randomly divided into two subgroups: the development cohort (n = 635) and validation cohort (n = 272). Univariate analysis and backward elimination of multivariate logistic regression analyses were utilized to identify predictive factors, and a nomogram was established. The performance was assessed using the area under the curve (AUC), the mean AUC of k-fold cross-validation, and calibration plots. Based on the classification and regression tree model, risk classification was performed. Results: The score included five commonly available predictors: body mass index, proteinuria, age, uric acid, and mean arterial pressure (BPAUM score). When applied to internal validation, the score revealed good discrimination with stratified fivefold cross-validation in the development cohort (AUC = 0.91) and validation cohort (AUC: 0.89) at fixed 10% false-positive rates, and the calibration plots showed good calibration. The total score point was divided into three risk classifications: low risk (0 - 179 points), medium risk (179 - 204 points), and high risk (>204 points). Conclusions: This study established a prediction model for predicting PIH, which could be used in clinical decision-making to improve maternal health and birth outcomes.

Uric acid levels in gestational hypertensive women predict preeclampsia and outcome of small-for-gestational-age infants

OBJECTIVE

This study aims to ascertain whether serum uric acid is a suitable predictor of preeclampsia and/or the delivery of small-for-gestational-age infants for women with gestational hypertension.

METHODS

364 singleton pregnant women with initial presentation of gestational hypertension were recruited and followed up until 6 weeks after delivery. Uric acid z score and binary logistic regression analysis were applied to establish the relationship between serum uric acid and the chance of progression to preeclampsia and giving birth to a small-for-gestational-age infant. Furthermore, receiver operating characteristic (ROC) analysis was used to evaluate the prediction value of serum uric acid.

RESULTS

Uric acid z score and binary logistic regression analysis indicated that elevated serum uric acid increased the chances of gestational hypertension progression to preeclampsia and subsequent delivery of small-for-gestational-age infants. ROC analysis showed that serum uric acid at a cutoff value of 303μmol l-1, moderately predict the development of preeclampsia and the delivery of small-for-gestational age infants. The prediction values of preeclampsia were 90.7% sensitivity, 69.4% specificity, 97.7% negative predictor values and 34.0% positive predictor values, comparatively, the prediction value for small-for-gestational age infant was low. The ROC curve improved with 95.8% sensitivity, 86.7% specificity, 98.1% NPV, and 74.2% PPV in the Chinese Han women with early onset of gestational hypertension thus the diagnosis of gestational hypertension before 34 weeks.

CONCLUSIONS

Elevated serum uric acid in Chinese Han women with gestational hypertension indicated an increased risk of their progression to preeclampsia and the further delivering of small-for-gestational-age infants.

Biochemical tests of placental function versus ultrasound assessment of fetal size for stillbirth and small-for-gestational-age infants

BACKGROUND

Stillbirth affects 2.6 million pregnancies worldwide each year. Whilst the majority of cases occur in low- and middle-income countries, stillbirth remains an important clinical issue for high-income countries (HICs) - with both the UK and the USA reporting rates above the mean for HICs. In HICs, the most frequently reported association with stillbirth is placental dysfunction. Placental dysfunction may be evident clinically as fetal growth restriction (FGR) and small-for-dates infants. It can be caused by placental abruption or hypertensive disorders of pregnancy and many other disorders and factorsPlacental abnormalities are noted in 11% to 65% of stillbirths. Identification of FGA is difficult in utero. Small-for-gestational age (SGA), as assessed after birth, is the most commonly used surrogate measure for this outcome. The degree of SGA is associated with the likelihood of FGR; 30% of infants with a birthweight < 10th centile are thought to be FGR, while 70% of infants with a birthweight < 3rd centile are thought to be FGR. Critically, SGA is the most significant antenatal risk factor for a stillborn infant. Correct identification of SGA infants is associated with a reduction in the perinatal mortality rate. However, currently used tests, such as measurement of symphysis-fundal height, have a low reported sensitivity and specificity for the identification of SGA infants.

OBJECTIVES

The primary objective was to assess and compare the diagnostic accuracy of ultrasound assessment of fetal growth by estimated fetal weight (EFW) and placental biomarkers alone and in any combination used after 24 weeks of pregnancy in the identification of placental dysfunction as evidenced by either stillbirth, or birth of a SGA infant. Secondary objectives were to investigate the effect of clinical and methodological factors on test performance.

SEARCH METHODS

We developed full search strategies with no language or date restrictions. The following sources were searched: MEDLINE, MEDLINE In Process and Embase via Ovid, Cochrane (Wiley) CENTRAL, Science Citation Index (Web of Science), CINAHL (EBSCO) with search strategies adapted for each database as required; ISRCTN Registry, UK Clinical Trials Gateway, WHO International Clinical Trials Portal and ClinicalTrials.gov for ongoing studies; specialist abstract and conference proceeding resources (British Library's ZETOC and Web of Science Conference Proceedings Citation Index). Search last conducted in Ocober 2016.

SELECTION CRITERIA

We included studies of pregnant women of any age with a gestation of at least 24 weeks if relevant outcomes of pregnancy (live birth/stillbirth; SGA infant) were assessed. Studies were included irrespective of whether pregnant women were deemed to be low or high risk for complications or were of mixed populations (low and high risk). Pregnancies complicated by fetal abnormalities and multi-fetal pregnancies were excluded as they have a higher risk of stillbirth from non-placental causes. With regard to biochemical tests, we included assays performed using any technique and at any threshold used to determine test positivity.

DATA COLLECTION AND ANALYSIS

We extracted the numbers of true positive, false positive, false negative, and true negative test results from each study. We assessed risk of bias and applicability using the QUADAS-2 tool. Meta-analyses were performed using the hierarchical summary ROC model to estimate and compare test accuracy.

MAIN RESULTS

We included 91 studies that evaluated seven tests - blood tests for human placental lactogen (hPL), oestriol, placental growth factor (PlGF) and uric acid, ultrasound EFW and placental grading and urinary oestriol - in a total of 175,426 pregnant women, in which 15,471 pregnancies ended in the birth of a small baby and 740 pregnancies which ended in stillbirth. The quality of included studies was variable with most domains at low risk of bias although 59% of studies were deemed to be of unclear risk of bias for the reference standard domain. Fifty-three per cent of studies were of high concern for applicability due to inclusion of only high- or low-risk women.Using all available data for SGA (86 studies; 159,490 pregnancies involving 15,471 SGA infants), there was evidence of a difference in accuracy (P < 0.0001) between the seven tests for detecting pregnancies that are SGA at birth. Ultrasound EFW was the most accurate test for detecting SGA at birth with a diagnostic odds ratio (DOR) of 21.3 (95% CI 13.1 to 34.6); hPL was the most accurate biochemical test with a DOR of 4.78 (95% CI 3.21 to 7.13). In a hypothetical cohort of 1000 pregnant women, at the median specificity of 0.88 and median prevalence of 19%, EFW, hPL, oestriol, urinary oestriol, uric acid, PlGF and placental grading will miss 50 (95% CI 32 to 68), 116 (97 to 133), 124 (108 to 137), 127 (95 to 152), 139 (118 to 154), 144 (118 to 161), and 144 (122 to 161) SGA infants, respectively. For the detection of pregnancies ending in stillbirth (21 studies; 100,687 pregnancies involving 740 stillbirths), in an indirect comparison of the four biochemical tests, PlGF was the most accurate test with a DOR of 49.2 (95% CI 12.7 to 191). In a hypothetical cohort of 1000 pregnant women, at the median specificity of 0.78 and median prevalence of 1.7%, PlGF, hPL, urinary oestriol and uric acid will miss 2 (95% CI 0 to 4), 4 (2 to 8), 6 (6 to 7) and 8 (3 to 13) stillbirths, respectively. No studies assessed the accuracy of ultrasound EFW for detection of pregnancy ending in stillbirth.

AUTHORS' CONCLUSIONS

Biochemical markers of placental dysfunction used alone have insufficient accuracy to identify pregnancies ending in SGA or stillbirth. Studies combining U and placental biomarkers are needed to determine whether this approach improves diagnostic accuracy over the use of ultrasound estimation of fetal size or biochemical markers of placental dysfunction used alone. Many of the studies included in this review were carried out between 1974 and 2016. Studies of placental substances were mostly carried out before 1991 and after 2013; earlier studies may not reflect developments in test technology.

Maternal serum uric acid concentration and pregnancy outcomes in women with pre-eclampsia/eclampsia

Objectives

To determine the relationship between maternal serum uric acid levels and fetal/neonatal complications in women with pre‐eclampsia/eclampsia, and to establish a predictive threshold value.

Methods

A diagnostic test and historical cohort study conducted by prospective cross‐sectional data collection on pregnant women with pre‐eclampsia/eclampsia at Hue University Hospital, Vietnam, between March 2015 and July 2017. Pre‐eclampsia was diagnosed based on ACOG criteria. Serum uric acid levels were measured by enzymatic colorimetric testing using a Cobas c 501 analyzer (Roche Diagnostics, Mannheim, Germany). Fetal complications included intrauterine growth restriction, preterm delivery, fetal death, and neonatal death.

Results

There were 205 women enrolled. Serum uric acid at a cutoff of 393 μmol/L is a good predictor of fetal/neonatal complications (AUC 0.752), with 64.4% sensitivity and 79.5% specificity. High uric acid level (≥393 μmol/L) resulted in increased risk of preterm birth (OR 6.367, 95% CI 3.009–13.084), low Apgar scores (OR 5.514, 95% CI 1.877–16.198), intrauterine growth restriction (OR 7.188, 95% CI 3.592–14.382), and neonatal death (OR 7.818, 95% CI 1.614–37.867). There was no relationship between uric acid level and fetal death (OR 1.803, 95% CI 0.355–9.168).

Conclusions

Maternal serum uric acid concentration is a good predictor of fetal/neonatal outcomes in women with pre‐eclampsia/eclampsia.

Maternal serum uric acid concentration is a good predictor of fetal/neonatal outcomes in pregnant women with pre‐eclampsia/eclampsia.

First versus second trimester mean platelet volume and uric acid for prediction of preeclampsia in women at moderate and low risk

OBJECTIVE

To determine if second trimester mean platelet volume (MPV) and serum uric acid are reasonable predictors of preeclampsia (PE) or not, in patients at moderate and low risk.

METHODS

This prospective study was conducted on 9522 women at low or moderate risk for developing PE who underwent dual measurements of MPV and serum uric acid at late first trimester (10-12 weeks) and at second trimester (18-20 weeks) and subsequently divided into two groups; PE group (n = 286) who later developed PE and non-PE group (n = 9236). Test validity of MPV and serum uric acid was the primary outcome measure. Data were collected and analyzed.

RESULTS

Second trimester MPV is a good predictor for development of PE at a cutoff value of 9.55 fL with area under the curve (AUC) of 0.86, sensitivity of 95.2%, specificity of 66.7%, positive predictive value (PPV) of 87%, negative predictive value (NPV) of 85.7%, and accuracy of 86.7%. Second trimester serum uric acid is a good predictor for development of PE at a cutoff value of 7.35 mg/dL, with AUC of 0.85, sensitivity of 95.2%, specificity of 55.6%, PPV of 83.3%, NPV of 83.3%, and accuracy of 83.3%. Combination of both tests has a sensitivity of 100%, specificity of 22.2%, PPV of 75%, NPV of 100%, and accuracy of 76.7%.

CONCLUSION

Second trimester MPV and serum uric acid alone or in combination could be used as a useful biochemical markers for prediction of PE based on their validity, simplicity, and availability.

The association of hyperuricemia and immediate postpartum hypertension in women without a diagnosis of chronic hypertension

Our objective was to determine if elevated uric acid (UA) is associated with postpartum hypertension (PP HTN) in women without chronic hypertension. This is a secondary analysis of a randomized trial. We compared those with elevated UA to those with normal UA. Logistic regression was conducted to determine the association of elevated UA with PP HTN. Five hundred and fifty-six women met criteria. An UA level ≥ 5.2 mg/dL was associated with immediate PP HTN (adjusted odds ratio 2.44, 95% CI 1.63-3.64). The association was stronger among overweight and obese women. We conclude that hyperuricemia is associated with PP HTN, especially among obese women.

The Role of Uric Acid in Preeclampsia: Is Uric Acid a Causative Factor or a Sign of Preeclampsia?

PURPOSE OF REVIEW

Because of the significant discrepancies on this topic, this review will focus on the role of uric acid in PE, uric acid as a predictor of preeclampsia and fetal growth retardation. We considered eligible review and original articles relevant to the research question.

RECENT FINDINGS

Hypertensive disorders of pregnancy such as preeclampsia (PE) are a major cause of both maternal and fetal morbidity and mortality worldwide. Uric acid has been reported as a key factor contributing to the pathogenesis of PE. Some studies have indicated that serum uric acid levels increase with the severity of PE, while several studies have shown contradictory results. Some studies suggested high uric acid levels lead to PE, while others state that PE causes an increase in uric acid levels. Despite the strong association of uric acid in the pathogenesis of preeclampsia, current data is still contradictory hence genetic and high-end laboratory investigations may clarify this enigma.

Predictive Value of Maternal Serum Biomarkers for Preeclampsia and Birth Weight: A Case-Control Study in Chinese Pregnant Women

BACKGROUND

In clinical practice, abnormal biochemical changes often occur in women who eventually develop preeclampsia (PE). The study aims to investigate whether maternal serum biochemical markers in the early third trimester can predict PE and neonatal birth weight.

STUDY DESIGN

A retrospective case-control study was performed on 287 women who subsequently developed PE (mild = 139; severe = 148) and 143 healthy women. Fasting venous blood samples of all gravidas were drawn for routine biochemical markers screening in the early third trimester (28.49 ± 1.63 weeks). Appropriate statistical methods were selected for analysis with SPSS software.

RESULTS

(1) The concentrations of plasma triglyceride (TG), low-density lipoprotein cholesterol (LDL), and uric acid (UA) in the severe and mild subgroups of the PE group were significantly higher compared with the respective levels in the normal pregnancy groups (3.90 vs. 4.03 vs. 3.14 mmol/L; 3.41 vs. 3.33 vs. 2.89 mmol/L; 365.42 vs. 318.91 vs. 284.69 μmol/L; p < 0.0001). Serum calcium levels in PE group were significantly lower than those in control group (2.10 vs. 2.18 vs. 2.22 mmol/L; p < 0.0001). (2) By using the receiver operating characteristic curve to estimate the diagnosis rate of screening for PE of each marker, the highest sensitivity appeared by the combination of TG, total cholesterol (TC), LDL, high-density lipoprotein cholesterol (HDL), LDL/HDL, UA, Ca²⁺, and homocysteine (HCY) (79%). The area under curve (AUC) of UA was 0.70, which was the highest among these eight markers, but the AUC of an eight-marker combination model (0.85) had a better diagnostic indication. (3) In PE, the maximum systolic/diastolic blood pressure was significantly positively correlated with serum UA (r = 0.212/0.205, p < 0.0001); and negatively correlated with serum total calcium (r = -0.193/-0.196, p = 0.001). The neonatal birth weight of PE group had a positive correlation with serum TG levels (r = 0.141, p = 0.017) and serum total calcium levels (r = 0.221, p < 0.0001), and a negative correlation with UA levels (r = -0.265, p < 0.0001).

CONCLUSION

The individual marker really performs terrible in predicting PE. Joint monitoring and evaluation of these parameters may improve the screening efficiency for the prediction of PE and poor fetal growth early.

Relationship of serum uric acid, serum creatinine and serum cystatin C with maternal and fetal outcomes in rural Indian pregnant women

BACKGROUND

Hypertensive disorders are the most common in pregnancy. Several studies showed a positive correlation between elevated maternal serum uric acid (UA), serum creatinine and adverse maternal and fetal outcomes, but only a few studies are available on serum cystatin C and maternal and fetal outcomes. The present study was undertaken to study the association of serum UA, creatinine and cystatin C with maternal and fetal outcomes.

METHODS

Out of 116 pregnant women 69 women had no hypertension and 47 had hypertension with or without proteinuria. Serum UA, creatinine and cystatin C was measured by modified Uricase method, modified kinetic Jaffe's reaction and particle-enhanced immunonephelometric assay respectively. Multivariate logistic regression was performed to determine the independent effects of serum UA, creatinine and cystatin C on maternal and fetal outcomes using stata 13.1.

RESULTS

The adjusted odds ratio (OR) was 3.73 (95% CI: 1.18-11.75; P=0.024) for UA; 15.79 (95% CI: 3.04-81.94; P=0.001) for creatinine and 2.03 (95% CI: 0.70-5.87; P=0.192) for cystatin C in hypertensive disorders of pregnancy. All the three renal parameters were not significantly associated with birth weight, gestational age of delivery and mode of delivery after adjusting for the confounding factors.

CONCLUSIONS

Serum creatinine and uric acid are independent risk factors for hypertensive disorders of pregnancy. High serum uric acid is associated with low birth weight and delivery by caesarian section whereas high serum creatinine with preterm delivery only before adjustment for confounding factors and not after adjustment. Serum cystatin C was not significantly associated with the maternal and fetal outcomes.

Pregnancy and hemolysis, elevated liver enzymes and low platelet count syndrome in patients with Eisenmenger's syndrome

Eisenmenger's syndrome is characterized by a right-to-left or bidirectional shunt in congenital heart diseases. Hemolysis, elevated liver enzymes and low platelet count (HELLP) syndrome, commonly occurring during pregnancy, includes hemolysis, elevated liver enzymes and low platelet counts. HELLP syndrome and pregnancy are extremely rare in patients with Eisenmenger's syndrome. The authors report 4 cases of pregnancy complicated by the HELLP and Eisenmenger's syndrome and describe their initial intervention and the in-hospital outcomes of these cases. Special emphasis is given to elaborate about the hemodynamic monitoring, magnesium sulphate for convulsions, corticosteroid treatment, anticoagulation therapy, management of pulmonary hypertension, the timing of delivery, and blood product transfusion.

Prognostic significance of serum uric acid in women with gestational hypertension

Aim of our study was to ascertain, prospectively, whether serum uric acid is a suitable predictor of preeclampsia and/or the delivery of small-for-gestational-age infants in women with gestational hypertension. We screened 206 primiparas, with a singleton pregnancy, referred for recent onset of hypertension. At presentation, we measured serum uric acid, creatinine, blood glucose, hemoglobin and platelet level, and 24-hour proteinuria, as well as office and 24-hour blood pressures. We followed the women until 1 month after delivery and recorded pregnancy outcome. After logistic regression analysis, uric acid resulted a significant predictor of preeclampsia, with an unadjusted odds ratio of 9.1 (95% CI: 4.8 to 17.4; P<0.001); after adjustment for age, gestation week, hemoglobin and platelet levels, serum creatinine, office and 24-hour average systolic and diastolic blood pressures, it was 7.1 (95% CI: 3.2 to 15.7; P<0.001). Regarding the association between maternal serum uric acid and the chance of giving birth to a small-for-gestational-age infant, the unadjusted odds ratio was 1.7 (95% CI: 1.4 to 2.2; P<0.001), and it was 1.6 (95% CI: 1.1 to 2.4; P=0.02) after adjustment. Receiver operating characteristic analysis showed that serum uric acid, at a 309-μmol/L cutoff, predicted the development of preeclampsia (area under the curve: 0.955), with 87.7% sensitivity and 93.3% specificity, and the delivery of small-for-gestational-age infants (area under the curve: 0.784) with 83.7% sensitivity and 71.7% specificity. In conclusion, the results of our study show that serum uric acid is a reliable predictor of preeclampsia in women referred for gestational hypertension.