The use of the first trimester (AST × LDH × urea) / (platelet × hemoglobin) index in the prediction of preeclampsia

To evaluate the association between the first-trimester ALU-PH index, calculated from routinely available laboratory parameters, and the subsequent development of preeclampsia. This retrospective case-control study included 206 singleton pregnancies followed at a tertiary referral center between January 2020 and December 2024. The study population comprised 98 women who subsequently developed preeclampsia and 108 normotensive controls. First-trimester laboratory parameters obtained between 11 and 13 + 6 weeks of gestation were used to calculate the ALU-PH index according to the formula: (AST × LDH × BUN) / (platelet × hemoglobin). Demographic, obstetric, and laboratory variables were compared between groups. Receiver operating characteristic (ROC) curve analysis was performed to assess the discriminatory performance of the ALU-PH index for predicting preeclampsia. Gestational age at delivery was significantly lower and 24-hour urinary protein excretion was significantly higher in the preeclampsia group than in the control group (both p < 0.001). Among first-trimester laboratory parameters, AST levels were significantly higher in women who subsequently developed preeclampsia (18.26 ± 10.69 vs. 15.10 ± 7.31 U/L, p = 0.003), whereas the ALU-PH index was significantly lower in this group (15.46 ± 17.94 vs. 18.35 ± 17.00, p = 0.015). No significant differences were observed for maternal age, gravida, parity, BUN, LDH, platelet count, or hemoglobin levels. In ROC analysis, the ALU-PH index showed weak but statistically significant discriminatory performance for predicting preeclampsia, with an AUC of 0.598, sensitivity of 60.2%, specificity of 57.4%, and a cut-off value of 12.25. The first-trimester ALU-PH index was significantly associated with subsequent preeclampsia; however, its discriminatory performance was weak and insufficient for standalone clinical use. The ALU-PH index may be considered an exploratory, low-cost adjunct marker, but prospective validation in larger and phenotype-stratified cohorts is required.