Oxidative stress is associated with adverse pregnancy outcomes, and vitamin E has powerful anti-oxidant properties with the potential to impact health outcomes. Tocopherol isomers of vitamin E differ in their ability to modulate inflammation and vary in concentration in diets containing high proportions of processed versus unprocessed foods. The purpose of this study was to compare vitamin E status and associated pregnancy outcomes (mode of delivery, chorioamnionitis, APGARs (measure of appearance, pulse, grimace, activity, respiration), gestational age at delivery, and fetal growth) between maternal⁻infant dyads in a developed and a developing nation to identify potentially modifiable differences that may impact pregnancy and neonatal outcomes and provide a way to improve maternal and neonatal health. Plasma tocopherol levels were evaluated in 189 Midwestern United States (US) mother⁻infant pairs and 99 Central Nigerian mother⁻infant pairs. Maternal and infant concentrations of α-, γ-, and δ-tocopherol were measured using HPLC with diode-array detection. Descriptive statistics were calculated and tocopherol concentrations were associated with clinical outcomes such as mode of delivery, chorioamnionitis, APGARS, and fetal growth. Alpha- and γ-tocopherol levels were higher in the US mothers, (alpha: 12,357.9 (175.23⁻34,687.75) vs. 8333.1 (1576.59⁻16,248.40) (mcg/L); p < 0.001) (gamma: 340.7 (224.59⁻4385.95) vs. 357.5 (66.36⁻1775.31) (mcg/L); p < 0.001), while δ-tocopherol levels were higher in the Nigerian mothers (delta: 261.7 (24.70⁻1324.71) vs. 368.9 (43.06⁻1886.47) (mcg/L); p < 0.001). US infants had higher γ-tocopherol levels than Nigerian infants (203.1 (42.53⁻1953.23) vs. 113.8 (0.00⁻823.00) (mcg/L); p < 0.001), while both the Nigerian mothers and infants had higher α:γ-tocopherol ratios (8.5 vs. 26.2, and 8.9 vs. 18.8, respectively; p < 0.001). Our results in both populations show associations between increased circulating γ-tocopherol and negative outcomes like Caesarian sections, in contrast to the associations with positive outcomes such as vaginal delivery seen with increased α:γ-tocopherol ratios. Growth was positively associated with α- and γ-tocopherols in cord blood in the US population, and with cord blood δ-tocopherols in the Nigerian population. Tocopherol levels likely impact health outcomes in pregnancy in a complicated metabolism across the maternal⁻fetal axis that appears to be potentially influenced by culture and available diet.
Keywords: Nigeria; United States; infant; maternal; pregnancy; tocopherols; vitamin E.