The Role of Chemical Pathology in Maternal and Neonatal Health: A Review of Diagnostic Applications and Clinical Outcomes

Background: Chemical pathology (clinical biochemistry) is central to perinatal medicine, delivering objective data from maternal blood, urine, and neonatal samples to detect, monitor, and manage disorders affecting pregnancy and new-born health. Pregnancy induces major physiological changes in renal, hepatic, endocrine, metabolic, and electrolyte systems, requiring trimester-specific reference intervals to distinguish normal adaptations from pathology and prevent diagnostic errors. Key Diagnostic Applications: Biochemical testing enables early identification of preeclampsia (elevated uric acid, proteinuria), gestational diabetes mellitus (~14–17% global prevalence; glucose tolerance testing), intrahepatic cholestasis of pregnancy (total serum bile acids ≥19 μmol/L non-fasting), thyroid dysfunction (trimester-adjusted TSH/free thyroxine), and hypertriglyceridemia. Timely interventions reduce maternal complications (hypertensive crises, acute kidney injury up to 30%, HELLP syndrome) and foetal/neonatal risks (macrosomia, preterm birth, and stillbirth). Neonatal and Emerging Roles: Tandem mass spectrometry–based new-born screening detects treatable inborn errors of metabolism and congenital hypothyroidism from dried blood spots, achieving 50–90% reductions in mortality and severe morbidity in affected cases. Postnatal monitoring of glucose, bilirubin, and electrolytes supports high-risk infants. Emerging biomarkers to prenatal exposures (PFAS, phthalates, and heavy metals) are associated with growth restriction and developmental delays. Evidence and Challenges: Gestational diabetes screening reduces macrosomia and caesarean rates by 20–30%; integrated biochemical care lowers perinatal morbidity by 20–41%. Challenges include inconsistent reference intervals, assay interferences, access disparities in low-resource settings, and limited environmental toxin monitoring. This review advocates standardized guidelines, equity-focused research, AI integration, and expanded screening to optimize global maternal and neonatal outcomes.