J Obstet Gynaecol Res. 2026 Oct;52(10):e70518. doi: 10.1111/jog.70518.

ABSTRACT

OBJECTIVE: To evaluate whether the admission blood urea nitrogen to albumin ratio (BAR) predicts adverse maternal and perinatal outcomes in preeclampsia, and to compare its performance against six other laboratory-derived ratios.

METHODS: Records of 252 preeclamptic pregnancies were reviewed and dichotomised at a BAR cut-off of 3.0: low (< 3.0, n = 135) and high (≥ 3.0, n = 117). Composite adverse maternal outcomes included severe complication, intensive-care admission, or transfusion; composite adverse perinatal outcomes included growth restriction, stillbirth, neonatal death, neonatal-unit admission, or 5-min Apgar below 7. BAR was benchmarked against six other ratios: uric acid/albumin ratio (UAR), lactate dehydrogenase/albumin ratio (LAR), C-reactive protein/albumin ratio (CAR), fibrinogen/CRP ratio, fibrinogen/albumin ratio (FAR), and aspartate aminotransferase/alanine aminotransferase (AST/ALT) ratio (De Ritis) by ROC analysis. Independent predictors were sought through multivariable logistic regression.

RESULTS: Patients in the high-BAR stratum showed substantially higher rates of composite adverse obstetric outcome (78.6% vs. 54.1%; p < 0.001), composite adverse maternal outcome (28.2% vs. 6.7%; p < 0.001), maternal intensive-care admission (16.2% vs. 3.7%; p = 0.001), and transfusion (12.0% vs. 2.2%; p = 0.002). BAR yielded the most balanced discrimination across endpoints, with AUCs of 0.68 (95% CI: 0.61-0.75) for the obstetric composite, 0.74 (95% CI: 0.65-0.83) for the maternal composite, and 0.66 (95% CI: 0.59-0.73) for the perinatal composite (all p < 0.01); fibrinogen/albumin and AST/ALT ratios were not predictive. BAR did not differ significantly from UAR or LAR by DeLong test (all p > 0.05) and retained independent association with adverse perinatal outcome after adjustment (adjusted OR 1.32; 95% CI: 1.03-1.70; p = 0.03). Sensitivity analyses showed that UAR retained independent significance for all three composite endpoints, positioning BAR and UAR as complementary bedside markers.

CONCLUSION: An elevated admission BAR identifies preeclamptic women at higher risk of severe maternal and perinatal events, with performance comparable to that of UAR. Both BAR and UAR may serve as simple complementary bedside adjuncts to existing risk stratification tools in preeclampsia.

PMID:42853129 | DOI:10.1111/jog.70518