Abstract： Objective To investigate the relationship between recurrent spontaneous abortion (RSA) and the level of interferon-γ(IFN-γ) and interleukin-4 (IL-4) in peripheral blood and gingival crevicular fluid of patients with chronic periodontitis.Methods Fifty pregnant women with recurrent spontaneous abortion(gestational age: 5-28 weeks) and 40pregnant women (gestational age: 39-41 weeks)were included and their periodontal status was examined.The level of IFN-γ and IL-4 in gingival crevicular fluid and peripheral blood was detected by enzyme-linked immunosorbent assay.Results Nine RSA women and 5 in control group had periodontitis.The prevalence of periodontitis in RSA group was 18％ (9/50) and 13％ (5/40) in the control group(P ＜0.05).The probing depth,attachment loss and bleeding index in RSA group were higher than those in the control group(P ＜0.05).The level of IFN-γwas (52.98 ± 17.56) ng/L in gingival crevicular fluid of RSA group and (25.25 ± 7.93) ng/L in control group(P ＜ 0.01).The level of IL-4 was (15.43 ± 1.77) ng/L in gingival crevicular fluid of RSA group and (19.62 ± 4.04) ng/L in control group (P ＜0.01).The content of IFN-γwas (27.79 ± 3.59) ng/L in peripheral blood of RSA group and (18.39 ±2.65) ng/L in control group(P ＜0.05).The content of IL-4 was (15.88 ± 0.95) ng/L in peripheral blood of RSA group and (22.98 ± 4.30) ng/L in control group (P ＜ 0.001).The content of cytokines in gingival crevicular fluid and peripheral blood in the same group was positively related (r ＞ 0.8,P ＜ 0.001).Conclusions Pregnant women of RSA have a higher chance of getting periodontitis.The change in the level of cytokines in periodontal tissue could result in excursion of maternal intrauterine immune environment to T-helper 1 (Th1).Periodontitis was related to RSA.