Value of Maternal Renal Function Indicators in Predicting Small for Gestational Age Infants in Patient with Severe Preeclampsia

Background: Severe preeclampsia poses significant health risks to both pregnant patients and their newborns. Our goal was to explore the association between serum renal function related indicators in pregnant patients with severe preeclampsia and the occurrence of small for gestational age (SGA) infants, as well as to further identify independent risk factors for SGA based on these indicators. Methods: This was a retrospective case-control study. We evaluated the renal function indicators of 127 severe preeclampsia pregnant patients and 127 normal pregnant patients antenatally who delivered in Shijiazhuang Fourth Hospital from January 2022 to December 2022. Mann-Whitney U test and Chi-square test were used to compare the differences in clinical data between two groups. Spearman correlation analysis was used to determine the correlation between renal function indicators and newborn weight in severe preeclampsia pregnant patients. Receiver operating characteristic (ROC) curve was used to determine the optimal critical values of the above indicators, and multivariate logistic regression analysis was used to determine the independent risk factors for severe preeclampsia combined with SGA. Results: Blood urea nitrogen (BUN), serum creatinine (SCr) and serum uric acid (SUA) in severe preeclampsia patients with SGA were higher than severe preeclampsia without SGA (p < 0.05 vs. all groups). In the severe preeclampsia group, these indicators were significantly negatively correlated with birth weight (p < 0.001 vs. all groups), whereas no correlation was observed in the control group. In the severe preeclampsia group, a ROC analysis was performed based on whether the infants were small for gestational age, and the indicators were divided into two groups according to the optimal cut-off value. After adjusting for confounding factors, elevated BUN (≥4.9 mmol/L) served as an independent risk factor for severe preeclampsia patients with SGA (odds ratio (OR) = 4.336, 95% confidence interval (95% CI): 1.781–10.552, p = 0.001), and the corresponding area under the curve was 0.661 (0.572, 0.743). Conclusions: Serum renal function indicators in pregnant patients with severe preeclampsia were significantly associated with the occurrence of small for gestational age (SGA) infants. Moreover, elevated maternal BUN levels (≥4.9 mmol/L) prior to delivery may indicate the occurrence of SGA. However, we also acknowledge that the predictive power of this single marker is limited.