Impact of random urine proteinuria on maternal and fetal outcomes of pregnancy: a retrospective case-control study

Gestational hypertension and pre-eclampsia and risk of spontaneous premature rupture of membranes: A population-based cohort study

OBJECTIVE

To examine whether gestational hypertension and pre-eclampsia are associated with spontaneous premature rupture of membranes (PROM).

METHODS

A retrospective, population-based cohort study was conducted in Hebei, Zhejiang, and Jiangsu provinces in China from 1993 to 1995. After excluding women with missing data of exposure and outcome, history of chronic hypertension, multiple births, and babies with major birth defects and ambiguous sex, this study comprised 199 231 singleton live births. Logistic regression was used to evaluate the association, adjusting for potential confounders.

RESULTS

The incidence of PROM was 17.7% and 8.9% in women with gestational hypertension and pre-eclampsia, respectively, and 5.9% for the normotensive group. Compared with normotension, gestational hypertension was associated with an increase in the odds of PROM of 4.21 times (95% confidence interval [CI] 3.77-4.70), while pre-eclampsia had an increase of 2.27 times (95% CI 1.78-2.88). Additionally, women with hypertensive disorders of pregnancy had higher risks for term PROM (adjusted risk ratio [RR] 3.83, 95% CI 3.43-4.27) than preterm PROM (adjusted RR 3.10, 95% CI 2.18-4.41). Consistent results of the association were also observed in the sensitivity analyses.

CONCLUSION

Gestational hypertension and pre-eclampsia were associated with an increased risk for PROM. Increased odds were observed for term PROM compared with preterm PROM.

The Association Between GFR Evaluated by Serum Cystatin C and Proteinuria During Pregnancy

Introduction

Physiological changes in pregnancy result in increased cardiac output and renal blood flow, with a consequential increase in proteinuria. Data from studies of the relationship between proteinuria caused by isolated proteinuria and glomerular filtration rate (GFR) are still limited. The objective of this study was to investigate the effects of isolated proteinuria on the cystatin C–based GFR in the third trimester of pregnancy.

Methods

Data were collected from pregnant women in their third trimester whose serum creatinine levels were normal. The GFR of each participant was measured using serum cystatin C levels, and proteinuria was measured using urine protein–creatinine ratios. The participants were divided into 3 groups according to their level of proteinuria: normal (<150 mg/d), physiological (150–300 mg/d), and gestational (>300 mg/d). Changes in GFR were recorded for each group.

Results

The study included 89 participants, of whom 66.3% had levels of proteinuria that did not differ from that of the normal population (<150 mg/d). The incidence of physiological and gestational proteinuria was 21.4% and 12.4%, respectively. The results demonstrate that proteinuria >101.50 mg/d was significantly associated with declined estimated glomerular filtration rate (eGFR) (r = –0.34, P = 0.01). The analysis found that proteinuria >491.27 mg/d led to a risk of GFR <90 ml/min with an odds ratio of 12.69, P = 0.02 when adjusted for systolic blood pressure (SBP), diastolic blood pressure (DBP), and body mass index.

Conclusion

This study suggests that the term “physiological proteinuria” is a misnomer. When used in the traditional manner, creatinine level has inadequate sensitivity to estimate GFR in pregnant women. We found that there is a significant decline in GFR when urine protein > 101.5 mg/d, which could be an early biomarker for renal pathology rather than pregnancy physiology, suggesting that further workup and precaution is required.