Introduction: Hormonal changes during pregnancy leads to changes in most of body organs including oral cavity and saliva. This study has been done in order to evaluate the changes of salivary oxidant-antioxidant system during pregnancy. Materials and methods: This cross-sectional study has been done on pregnant women referring to obstetrics and gynecology clinic of Rouhani hospital, Babol, Iran, during 2014-2015. Forty eight pregnant womenwere selected and divided in two groups of 24 pregnant mothers including: group 1: first trimester pregnant women, group 2: second trimester pregnant women. Saliva samples of all mothers were gathered with spitting method and recollected again after 3 months. Total Antioxidant Capacity (TAC) andMalondialdehyde (MDA) level were measured by FRAP(Ferric Reducing Antioxidant Power) andTBARS(Thiobarbituric acid Reactive substances), respectively. Cabonyl level was measured by carbonyl kit. Data were analyzed by SPSS-18. Results: Two of pregnant mothers in each group were excluded because of abortion and 22 pregnant mothers were remained. Oxidant-antioxidant serum levels of MDA (p=0.31), carbonyl (p=0.74) and TAC (p=0.61) were not significantly changed in second trimester comparing to first trimester in the first group. In the third trimester, TAC level was significantly higher than the second trimester (p=0.02), however, this was not applicable for MDA and carbonyl levels. Comparison of third trimester/second trimester ratio with third trimester/second trimester ratio was insignificant in all oxidant-antioxidant parameters. Discussion and conclusion: Results revealed that level of MDA and carbonyl oxidants do not have any significant changes during pregnancy and total antioxidant capacity is the only parameter which remarkably increases in third trimester comparing to second trimester.
