Lactate in pregnancy and labor: current evidence and future perspectives for fetal surveillance

Abstract The assessment of fetal well-being remains challenging. Despite the development of several surveillance methods, preventing metabolic acidosis and adverse neonatal outcomes without increasing unnecessary obstetric intervention remains difficult. Lactate levels have been evaluated in maternal blood, umbilical cord blood, fetal scalp blood, and, with growing interest, amniotic fluid. Although lactate exchange between the maternal, uteroplacental, and fetal compartments is not fully understood, amniotic fluid lactate (AFL) has been investigated as a potential marker of uterine metabolic activity and labor progression. Higher AFL concentrations have been associated with labor dystocia and operative delivery in some studies. Accordingly, AFL assessment may provide complementary information on labor progression, but its potential role as an adjunct to fetal surveillance and routine clinical decision-making requires further investigation and validation. Interventions aimed at reducing elevated AFL concentrations during labor have also been proposed. However, evidence that AFL-guided treatment improves obstetric or neonatal outcomes remains limited. Further technological development and prospective clinical validation may clarify whether AFL assessment could support existing maternal and fetal surveillance strategies. This narrative review examines lactate physiology during pregnancy and labor and evaluates the potential role of lactate measurements as adjunctive biomarkers and as possible guides for future therapeutic strategies.