Abstract: Objective To examine the association between gum bleeding in the first trimester of pregnancy and pregnancy-related anxiety.Methods Subjects were 5 084 pregnant women who had joined in the Ma'anshan Birth Cohort Study and delivered between October 2008 and October 2010.All participants were asked to complete a self-administered questionnaire to collect information on demographic characteristics,pregnancy history,diseases history,gum bleeding,and pregnancy-related anxiety.Descriptive statistics and logistic regression models were used in data analyses.Results Among the women,the self-reported rates of oral hemorrhage or the smell of blood in the morning,gum bleeding when eating hard food,and gum bleeding when brushing teeth were 19.2%,17.8%,and 52.2%,respectively.And the prevalences of mild gingivitis and moderate to severe gingivitis diagnosed by doctors were 24.4% and 8.9%.After adjusting for sociodemographic characteristics,pregnancy history and disease history,the results of logistic regression showed that the women with oral hemorrhage or the smell of blood in the morning 1-2 times in a week had 1.33 of odds ratio (OR)(95% confidence interval95%CI:1.10-1.61) for pregnancy-related anxiety and those with the symptoms ≥3 times in a week had the OR of 1.83(95%CI:1.44-2.31).The women with gum bleeding when eating food 1-2 times in a week had the OR of 1.40(95%CI:1.17-1.67)for pregnancy-related anxiety and those with the symptoms ≤3 times in a week had the OR of 1.62(95%CI:1.18-2.23),and the women with gum bleeding when brushing teeth ≥3 times in a week had an OR of 1.40 (95%CI:1.20-1.64) for pregnancy-related anxiety.The gingival index was highly reversely associated with pregnancy-related anxiety (OR=1.37,95%CI:1.10-1.71).Conclusion Gum bleeding is a very common problem among pregnant women in the first trimester of pregnancy and should be properly treated for the improvement of mental health of the pregnant women.