The Cariostat caries activity test (CAT) was used to evaluate the effectiveness of personalized oral hygiene management combining oral health education and professional mechanical tooth cleaning on the oral health status of pregnant women. To investigate whether personalized oral hygiene management enhances the oral health status of pregnant women. A total of 114 pregnant women who were examined at Dalian Women's and Children's Medical Center were divided into four groups: High-risk experimental group (n = 29; CAT score ≥ 2; received personalized oral hygiene management training), low-risk experimental group (n = 29; CAT score ≤ 1; received oral health education), high-risk control group (n = 28; CAT score ≥ 2), and low-risk control group (n = 28; CAT score ≤ 1). No hygiene intervention was provided to control groups. CAT scores at different times were compared using independent samples t-test and least significant difference t-test. No significant difference in baseline CAT scores was observed between the experimental and control groups, either in the high-risk or low-risk groups. CAT scores were reduced significantly after 3 (1.74 ± 0.47 vs 2.50 ± 0.38, P < 0.0001) and 6 months (0.53 ± 0.50 vs 2.45 ± 0.42, P < 0.0001) of personalized oral hygiene management intervention but not after oral health education alone (0.43 ± 0.39 vs 0.46 ± 0.33, P > 0.05 and 0.45 ± 0.36 vs 0.57 ± 0.32, P > 0.05, respectively). Within groups, the decrease in CAT scores was significant (2.43 ± 0.44 vs 1.74 ± 0.47 vs 0.53 ± 0.50, P < 0.0001) for only the high-risk experimental group. Personalized oral hygiene management is effective in improving the oral health of pregnant women and can improve pregnancy outcomes and the oral health of the general population.