Association between proteinuria and adverse pregnancy outcomes: a retrospective cohort study

Proteinuria during pregnancy is closely related to the occurrence of adverse pregnancy outcomes. One hundred and forty-two women with proteinuria during pregnancy and followed between January 2018 and December 2020 were evaluated. Based on the 24-h proteinuria value, they were divided as mild (n = 76, 300-1000 mg/day), moderate (n = 39, 1000-3500 mg/day) and severe (n = 27, >3500 mg/day) proteinuria. The rates of prematurity, low birth weight and neonatal asphyxia were significantly higher in the severe proteinuria group than in the mild and moderate groups, while the rates of foetal growth restriction and neonatal intensive care unit admission were significantly higher in the severe compared with the mild proteinuria group (all p < .05). Logistic regression analysis showed that moderate proteinuria (OR = 97.2, 95%CI: 7.1-1334.2, p = .001) and severe proteinuria (OR = 34.0, 95%CI: 1.6-711.0, p = .023) were associated with adverse perinatal outcomes. Compared with mild proteinuria, moderate and severe proteinuria are associated with adverse pregnancy outcomes in perinatal infants.Impact Statement What is already known on this subject? The production of proteinuria is closely related to the filtration function of the glomerulus, the reabsorption and secretion function of the renal tubules. For women with normal renal function before pregnancy, such physiological changes are less likely to cause adverse symptoms; however, for women with chronic kidney disease before pregnancy, especially those with significantly impaired renal function, the kidneys often cannot compensate for these physiological changes, which can lead to serious complications for both mother and infant. What do the results of this study add? In our study, logistic regression analysis showed that the severity of proteinuria was independently associated with adverse perinatal outcomes. The ROC curve showed that 24-h proteinuria had a predictive value for adverse perinatal outcomes. Therefore, for patients with urine protein quantification >= 0.3 g/24 h, regular 24-h urine protein quantification during pregnancy could help predict adverse perinatal outcomes and improve prognosis. What are the implications of these findings for clinical practice and/or further research? Proteinuria quantification can be used as one of the factors predicting adverse pregnancy outcomes. Thus, monitoring of urinary protein quantification in women during pregnancy should be strengthened for early detection of renal impairment, then interventions be used to improve maternal and infant outcomes.