Oxidative Stress in Pregnant Women between 12 and 20 Weeks of Gestation and Preterm Birth

Background A known relationship exists between oxidative stress and preterm birth (PTB). However, few studies have measured oxidative stress prospectively in early or midpregnancy, and no studies have used electron paramagnetic resonance (EPR) spectroscopy prospectively to predict PTB. Objective The purpose of this study was to identify predictive relationships between antioxidants and reactive oxygen species (ROS), specifically, superoxide (O2•-), peroxynitrite (OONO-), and hydroxyl radical (●OH), using EPR spectroscopy, measured between 12 and 20 weeks of gestation and compare with the incidence of PTB. Methods Blood was obtained from pregnant women (n = 140) recruited from a tertiary perinatal center. Whole blood was analyzed directly for ROS, O2•-, OONO-, and ●OH using EPR spectroscopy. Red blood cell lysate was used to measure antioxidants. PTB was defined as parturition at <37 weeks of gestation. Results No differences were found between ROS, O2•-, OONO-, or ●OH with the incidence of PTB. Catalase activity, glutathione, and reduced/oxidized glutathione ratio were significantly lower with PTB. Logistic regression suggests decreased catalase activity in pregnant women is associated with increased odds of delivering prematurely. Discussion We prospectively compared antioxidants and specific ROS using EPR spectroscopy in pregnant women between 12 and 20 weeks of gestation with the incidence of PTB. Results are minimal but do suggest that antioxidants - specifically decreased catalase activity - in early pregnancy may be associated with PTB; however, these findings should be cautiously interpreted and may not have clinical significance.