Association between periodontal indexes and biomarkers in gingival crevicular fluid and preterm birth in pregnancy: a nested case-control study

Objectives: This study aimed to investigate the association between periodontal indexes and biomarkers in gingival crevicular fluid (GCF) and preterm birth (PTB) in pregnancy, as well as to assess the clinical value of these indexes as predictors of PTB.

Methods: A nested case-control study was conducted. A total of 300 systematically healthy pregnant women were selected within 36 weeks of gestation and grouped according to the enrolled weeks. Periodontal indexes, including probing depth (PD), bleeding index (BI), gingival index (GI), and five biomarkers in GCF, including interleukin (IL)-1β, IL-6, tumor necrosis factor-α (TNF-α), prostaglandin E2 (PGE2), and 8-hydroxy-2-deoxyguanosine (8-OHdG) were measured at the enrolled date. The detailed birth outcome was recorded.

Results: Only women at 24-28 weeks of gestation per PTB case (four full-term births) were selected as controls subjects, PTB displayed significantly greater GI, BI, and 8-OHdG (P<0.05). Logistic regression analysis revealed that BI and 8-OHdG were the dependent risk factors of PTB (OR=5.90, P=0.034; OR=1.18, P=0.045, respectively). The areas under the receiver operating characteristic curve (ROC) of BI and 8-OHdG were 0.80 and 0.69, and that of the combined detection was 0.82, which was larger than the individual detection, although the differences were not significant (P>0.05).

Conclusions: Increased BI and 8-OHdG at 24-28 weeks of gestation are risk factors for PTB. Their combined detection may have some value in the prediction of PTB, but further studies with a larger sample size are needed to explore it and thus provide experiment evidence for establishing an early warning system for PTB in pregnant women with periodontal disease.