Evaluating cord blood S100B protein concentration as a potential biomarker associated with fetal hypoxia in late fetal growth restriction: A prospective cohort study protocol

Introduction S100B protein is a biomarker associated with central nervous system (CNS) injury following hypoxic-ischemic events. Measurement of S100B levels in umbilical cord blood may provide a noninvasive means of identifying newborns exposed to perinatal hypoxia related to fetal growth restriction (FGR) immediately after birth. Early detection of infants at increased risk of hypoxia-related CNS injury could facilitate closer surveillance, prompt diagnostic evaluation, and timely implementation of appropriate interventions, potentially improving long-term neurodevelopmental outcomes. Methods and Analysis This study investigates two groups of full-term pregnancies: a study group with prenatally diagnosed late FGR, and a control group with normal fetal growth. Following delivery, cord blood samples from both groups will be analyzed for S100B protein concentrations, pH, base excess (BE), and lactate levels. Additionally, fetal blood flow parameters in the umbilical artery (UA), uterine arteries (UtA), ductus venosus (DV), and middle cerebral artery (MCA) will be assessed via ultrasound within 48 hours before delivery. This study aims to compare S100B protein concentrations in umbilical cord blood between the two groups and evaluate its correlations with fetal Doppler parameters, pH, BE, and lactate levels in cord blood gas analysis. Additionally, it will evaluate the potential utility of S100B protein concentration as a biomarker associated with perinatal hypoxic stress in FGR-affected neonates. Ethics and Dissemination The study received approval from the Bioethics Committee of the Institute of Mother and Child in Warsaw (Decision No. 13/2024, dated 21 March 2024). The findings will be submitted for publication in peer-reviewed journals specializing in neonatology, pediatrics, obstetrics, and perinatology. Additionally, abstracts will be submitted to relevant national and international conferences. Trial registration The study is registered at ClinicalTrials.gov (Identifier: NCT06893926 ).