Proteinuria may be an indicator of adverse pregnancy outcomes in patients with preeclampsia: a retrospective study

Background Proteinuria is one of the common manifestations of patients with preeclampsia (PE), but whether the severity of proteinuria is related to the pregnancy outcome of patients with preeclampsia remains controversial. The present study aimed to determine the relationship between 24-h proteinuria and adverse outcomes in patients with preeclampsia. Methods The present retrospective study included 329 pregnant women in Chongqing, China. Patients were divided into PE group and non-PE group. PE group was stratified into three subgroups based on the level of 24-h proteinuria. Correlation analysis was used to analyze the correlation between biochemical indexes and adverse pregnancy outcome, and Logistic regression analysis was used to analyze the risk factors of adverse pregnancy outcome. The receiver operating characteristic curve (ROC) was used to evaluate the ability of 24-h urinary protein to distinguish the adverse pregnancy outcome in patients with preeclampsia. Results (1) Between PE and non-PE group, cesarean section rate in PE group was significantly higher than that in non-PE group (84.4% vs. 25.9%, p < 0.001). Laboratory findings such as uric acid and creatinine level in PE group were higher than those in non-PE group. (2) Among mild (proteinuria < 0.3 g/24 h), moderate (0.3 g/24 h = 2 g/24 h) groups, the frequencies of induced labor (p = 0.006) and stillbirth (p = 0.002) increased with the increase of 24-h proteinuria. (3) Adverse outcomes were positively correlated with 24-h proteinuria (adverse maternal outcomes: r = 0.239, p = 0.002; adverse fetal outcomes: r = 0.336, p < 0.001). (4) The best 24-h proteinuria cutoff values to determine stillbirth, premature and fetal distress were 3965.0 mg/24 h, 984.75 mg/24 h and 1503.85 mg/24 h and their odds ratio (95% confidence interval) were 12.46 (3.46-44.88), 2.48 (1.15-5.37) and 10.02 (2.14-46.80), respectively. Conclusions The severity of 24-h proteinuia may forecast adverse outcomes in women with preeclampsia. We suggest proteinuria should be retained as one of the monitoring indexes in patients with preeclampsia.