PREGNANCY OUTCOME AND MATERNAL METHEMOGLOBIN LEVELS

Methemoglobinemia is a condition in which hemoglobin is oxidised to the ferric form and is unable to transport oxygen to tissues, therefore causing hypoxia. The level of methemoglobin in the blood is the biomarker often used in research for assessing exposure to nitrates. Although the literature on the effects of nitrates on methemoglobinemia and maternal health is sparse, reports are suggestive of an association between nitrates in drinking water and spontaneous abortion, pregnancy complications, intrauterine growth restriction and prematurity. The simultaneous exposure to environmental hazards such as nitrates during pregnancy could escalate oxidative stress and deplete antioxidant reserves, thus increasing the risk of adverse prenatal effects. Therefore, pregnant women may be more sensitive to the induction of clinical methemoglobinemia by exposure to nitrates levels below the maximum contaminant level (MCL). Methemoglobinemia is linked to complications during pregnancy and the measured methemoglobin level is a valuable biomarker of individual exposure. Recent data suggest that methemoglobin levels in blood drawn from the umbilical cord are excessively high for babies who were born preterm, and these levels are also elevated in low-birth weight babies, although not as much as in preterm babies.