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Antibody responses to Porphyromonas gingivalis outer membrane protein in the first trimester


: Dr Akira Kikuchi, Department of Obstetrics and Gynecology, Niigata University Graduate School of Medical and Dental Sciences, 1-754, Asahimachi-dori, Niigata City, Niigata 951-8510, Japan. Email:


Background: Porphyromonas gingivalis (Pg) is one of the most harmful periodontal pathogens and it has been reported that Pg is associated with preterm birth (PTB), intrauterine growth retardation (IUGR) and pregnancy-induced hypertension (PIH), discovered by animal experiments and clinical research. The relationship between adverse pregnancy outcomes and maternal antibody response to Pg is controversial. On the other hand, the serum C-reactive protein (CRP) has been recognised as a reliable serum marker of periodontal disease.

Aims:  To determine the significance of antibody responses to Pg affecting pregnancy outcomes in the first trimester.

Methods:  A case–control study was carried out on women with PTB (n = 58), IUGR (n = 91), PIH (n = 32) and without any complications (control, n = 98). The serum level of the CRP and IgG1 against 40-kDa outer membrane protein of Pg (anti-40-kDa OMP Pg-IgG1) in the first trimester was measured.

Results:  The IUGR group, and PTB patients whose placentas were diagnosed as chorioamnionitis or whose vaginal flora included Lactobacilli, showed a lower level of anti-40-kDa OMP Pg-IgG1 than the control group. There was no difference in the serum CRP level between each case group and control group.

Conclusions:  These results suggest that a lack of humoral immunity against Pg in early pregnancy is associated with IUGR and some PTB.