Oxidative stress levels and oral bacterial milieu in the saliva from pregnant vs. non-pregnant women

Abstract

<i>Background</i> - Saliva plays a significant role in maintaining oral health and oral bacterial milieu. Difference in oxidative stress (OS) levels in saliva in conjunction with bacterial load between pregnant and non-pregnant women has not been studied previously. We hypothesized that the physiological changes in pregnancy alter oral bacterial milieu by promoting growth of <i>Streptococcus mutans</i> (SM) and <i>Lactobacillus</i> (LB), and increase OS in saliva. The aim of this study was to measure and compare the oral bacterial milieu, OS and total anti-oxidative capacity (TAC) in the saliva of pregnant and non-pregnant women.<p>

<i>Method</i> - In this cross-sectional study, we assessed oral bacterial milieu by culturing the SM and LB by using commercial kits, TAC by measuring 2, 2′-Azino-Bis-3-Ethylbenzothiazoline-6-Sulfonic Acid (ABTS) free radical scavenging activity spectrophotometrically and OS levels by measuring malondialdehyde (MDA) levels with commercial kits in the saliva of pregnant women (<i>n</i> = 38) at 18–20 weeks of gestation, who were compared with age-matching healthy non-pregnant women (<i>n</i> = 50).<p>

<i>Results</i> - <i>Streptococcus mutans</i> were found to be more abundant in the saliva of pregnant women compared with non-pregnant women (<i>p</i> = 0.003) but the difference was not significant for the LB (<i>p</i> = 0.267). TAC was found to be 46% lower in pregnant women’s saliva compared to non-pregnant women [optical density (OD) measured at 731 nm as 0.118 ± 0.01 vs. 0.063 ± 0.02; <i>p</i> < 0.001]. OS, expressed as saliva MDA levels, was found to be 16% higher in pregnant women compared to non-pregnant women (1.07 nM MDA vs. 0.92 nM MDA; <i>p</i> = 0.023).<p>

<i>Conclusion</i> - Pregnancy has an adverse impact on oral bacterial milieu as demonstrated by increased colonization with <i>Streptococcus mutans</i> together with higher OS levels and decreased TAC levels in saliva. This emphasizes the importance of improved oral hygiene and provision of oral healthcare services during pregnancy care.