Maternal exposure to exogenous nitrogen compounds and complications of pregnancy.

Increased lipid peroxidation and reduced antioxidant activity have been reported with pregnancy complications. Given that exogenous oxidants stimulate formation of lipid peroxides, the authors investigated the relationship between exposure to nitrogen-oxidizing species and pregnancy complications and took into account markers of antioxidant and oxidant status. The study sample included pregnant women who were from an area polluted by oxidized nitrogen compounds. Methemoglobin, a biomarker of individual exposure, was determined, as were measures of oxidant/antioxidant status, including glutathione balance and lipid peroxide levels. Only 10 women experienced normal pregnancies. The most common complications were anemia (67%), threatened abortion/premature labor (33%), and signs of preeclampsia (23%). Methemoglobin was elevated significantly in all three conditions, compared with normal pregnancies. Reduced:total glutathione decreased, whereas lipid peroxide levels increased. These results suggest that maternal exposure to environmental oxidants can increase the risk of pregnancy complications through stimulation of the formation of cell-damaging lipid peroxides and from a decrease in maternal antioxidant reserves.