Evaluation of the HALP Score in the Distinction Between Fetal Growth Restriction and Small for Gestational Age

Objective To assess whether the hemoglobin–albumin–lymphocyte–platelet (HALP) score distinguishes fetal growth restriction (FGR) from small for gestational age (SGA) and its association with composite adverse perinatal outcome (CAPO). Method This retrospective study included 444 singleton pregnancies (214 FGR; 230 SGA) at a tertiary center (2021–2023). FGR was defined as early‐onset (< 32 weeks) or late‐onset (≥ 32 weeks) by Delphi/ISUOG criteria. HALP was calculated at diagnosis as [hemoglobin × albumin × lymphocytes ÷ platelets]. CAPO comprised ≥ 1 of neonatal intensive care admission, Apgar < 7 at 5 min, cord pH < 7.2, or perinatal death. Group comparisons and ROC analyses were performed. Results FGR cases had lower HALP (31.5 vs. 40.0, p < 0.001) and higher CAPO (15% vs. 7%, p = 0.04) than SGA. They delivered earlier, with lower birthweight, cord pH, and more NICU admissions. HALP moderately differentiated FGR from SGA (AUC 0.667; cutoff < 26.8: 44% sensitivity, 81% specificity) but did not predict CAPO (AUC 0.542, p = 0.334). A biological gradient was observed (EO‐FGR < LO‐FGR < SGA; all p < 0.001). Conclusions HALP is decreased in FGR, especially in early‐onset cases, and somewhat differentiates FGR from constitutionally small SGA. While it does not predict short‐term morbidity, it could be a simple addition to Doppler assessments when evaluating suspected growth restriction.