Associations between systemic status, periodontal status, serum cytokine levels, and delivery outcomes in pregnant women with a diagnosis of threatened premature labor

Background: Threatened premature labor (TPL) often results in preterm birth (PB). The aim of the present study was to evaluate the associations of periodontal and general health conditions with TPL and PB in relation to serum cytokine levels and the composition of subgingival plaque. Methods: Eighty-eight women were enrolled in the study. Systemic conditions were assessed, and subgingival plaque samples obtained for bacterial analysis. Periodontal examinations included assessments of plaque, gingivitis, clinical attachment level, probing depth, and bleeding on probing. Serum cytokine levels also were analyzed. Gestational age at delivery was recorded, and the mothers were divided into a TPL or non-TPL group, and into a non-TPL-TB (term birth), non-TPL-PB, TPL-TB, or TPL-PB group, accordingly. Results: Forty subjects were classified as TPL and 18 as TPL-PB. There were significant differences between the TPL and non-TPL subjects in several of the systemic and periodontal parameters and serum cytokine levels. Significant differences were observed between the TPL-TB and TPL-PB groups in the percentage of Tannerella forsythensis (Tf, formerly Bacteroides forsythus), and the serum interleukin (IL)-8 and IL-1beta levels. Significant negative correlations between the gestational age at delivery and several periodontal parameters and serum IL-8 and IL-1beta levels, and significant positive correlations between periodontal status and serum IL-8 and IL-1beta levels, were observed. Conclusions: The TPL women revealed worsened periodontal conditions and elevated serum IL-8 and IL-1beta levels compared to the non-TPL women. The elevated levels of serum IL-8 and IL-1beta could have affected the maintenance of the proper uterine-fetus relationship, resulting in premature uterine contractions.