Pregnancy and Alcohol: Parameters of Endogenous Intoxication Depending on Blood Phosphatidylethanol Levels

BACKGROUND: Endotoxicosis is a multifactorial pathophysiological process that can significantly affect the mother–placenta–fetus system during gestation. Alcohol consumption is a potential aggravating factor for maternal health, associated with biochemical disturbances both in the mother and the fetus, and may increase the risk of endotoxicosis. AIM: The work aimed to assess endogenous intoxication in women at different stages of pregnancy by measuring the concentration of middle molecules in venous blood and its association with serum phosphatidylethanol (PEth) levels. METHODS: Endogenous intoxication was evaluated by middle molecules levels in pregnant women (n=163). In accordance with PEth 16:0/18:1 concentrations, groups of women were identified according to alcohol consumption levels: group 1 with PEth ≤8 ng/mL (non-drinkers, control); group 2 with 8–45 ng/mL (drinking less than one dose); group 3 with ≥45 ng/mL (drinking more than one dose). Measurements were performed at 6–12, 18–22, 28–32, and 38–40 weeks of gestation. Plasma samples were used for analysis. Middle molecules were determined at λ=238, 254, 260, and 280 nm, followed by calculation of distribution coefficients (238/260, 238/280, 280/254). RESULTS: Compared with controls, significant reductions in middle molecules levels (λ=238 nm) were observed in alcohol-consuming women at 28–32 weeks in both group 2 (p=0.013) and group 3 (p=0.003). Before delivery, middle molecules levels were lower in group 3 compared with controls (p=0.004). A significant decrease in middle molecules levels (λ=280 nm) was detected in group 3 compared with group 2 (p=0.017). In alcohol-consuming women, regardless of PEth 16:0/18:1 levels, significantly lower values of the peptide–nucleotide distribution coefficient 238/260 (p=0.007 and p 0.001 in groups 2 and 3, respectively) and aromaticity coefficient 238/280 (p=0.002 and p 0.001 in groups 2 and 3, respectively) were observed compared with controls at 28–32 weeks. Before delivery, decreases in these coefficients were noted only in group 2 (p=0.006 for 238/260; p=0.015 for 238/280). The 280/254 distribution coefficient was higher in alcohol-consuming women at 28–32 weeks compared with controls (p=0.003 and p=0.014 in groups 2 and 3, respectively). CONCLUSION: The findings indicate reduced levels of specific fractions of middle-molecular toxins reflecting both anabolic and catabolic pools in alcohol-consuming women, which may be associated with serious metabolic disturbances in the mother–placenta–fetus system. Distribution coefficients proved to be sensitive markers for monitoring endogenous intoxication in pregnant women, suggesting a predominance of catabolic processes with accumulation of catabolic products and a possible increased risk of preterm delivery, regardless of alcohol dose.