ObjectiveTo investigate the effects of periodontal basic therapy on pregnancy outcome and inflammatory cytokine of threatened abortion pregnant women.MethodsSelect 80 cases of pregnant women with threatened abortion symptoms as threatened abortion group and 86 cases of healthy pregnant women as normal pregnancy group. Select pregnant women with periodontitis from the above two groups, then randomly divided into treatment group and non-treatment group. For each treatment group the pregnant women were used periodontal treatment and regular maintenance, the non-treatment group accepted no special treatment except the oral hygiene instruction. Check the periodontal status [gingival sulcus bleeding index (SBI), probing depth (PD), and attachment loss (AL)] and the content of prostaglandin E2(PGE2), tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) in serum in week 16 of pregnancy and before delivery, record the pregnancy outcomes of each pregnant women.ResultsIn week 16 of pregnancy the SBI, PD and AL rate of threatened abortion group were higher than in normal pregnancy group, the difference was statistically significant. The improvement of SBI and PD before and after the periodontal treatment in threatened abortion and healthy pregnant women group have statistical significance. There was no significant difference in the content of PGE2, TNF-α and IL-6 before and after treatment in each group, there was no significant difference in the incidence of preterm low birth weight also.ConclusionPeriodontal therapy is safe for pregnant women and can effectively improve the periodontal status, but cannot change the level of inflammatory factors in the blood and the pregnancy outcomes.