Blood lactate concentrations are associated with markers of metabolic dysfunction during late pregnancy

The ability to detect metabolic dysfunction during pregnancy can impact the health of mother and infant(s). Lactate may serve as a biomarker to predict metabolic dysfunction risk. The purpose of this study was to determine if fasting or postprandial blood lactate concentrations were related to established markers of metabolic dysfunction during late pregnancy. Overnight fasted healthy women between 32-38 weeks gestation underwent a high-fat meal test. Fasted and postprandial (1h, 2h, and 4h) venous blood glucose, insulin, and lactate were collected. Fasted and postprandial (2h and 4h) respiratory exchange ratios (RERs) were assessed by indirect calorimetry. HOMA-IR and Matsuda indexes were calculated. Participants were categorized into lean (18.5-24.9 kg/m2), overweight (25.0-29.9 kg/m2), or obese (≥30.0 kg/m2) based on pre-pregnancy body mass index. To determine the impact that weight status may have on postprandial lactate concentrations, a repeated-measures analysis of variance was performed on log-transformed data. Spearman's rank-order correlation coefficients were used to assess associations between outcome variables. 52 participants were included in the analysis (lean, n = 29; overweight, n = 11; obese, n = 12). Postprandial lactate was higher in women with obesity compared to women who were lean (1h, p = 0.024; 2h, p = 0.025; 4h, p = 0.010). Among all women, higher lactate area under the curve (AUC) was associated with higher insulin AUC, higher HOMA-IR index, lower Matsuda index, and higher RER AUC (p ≤ 0.003). These findings suggest that postprandially elevated lactate may serve as a useful biomarker for identifying metabolic dysfunction during pregnancy.