Clinical, oral immunological and microbiological shifts during and after pregnancy

Abstract

Objectives: Physiological changes and shifts in the oral microbiota composition during pregnancy may affect the maternal immune system. Uncomplicated pregnancy is associated with a T-helper (Th) 2 predominant cytokine regulation (anti-inflammatory), while oral health deterioration during pregnancy is reflected by severe gingival inflammation, a primarily Th1 cytokine phenotype (pro-inflammatory), and oral microbiome alterations. This prospective observational study aimed to evaluate Th cytokine shifts and changes in the oral microbiota composition in saliva of women before and after birth.

Material and methods: Saliva (n = 96) was collected before and 6 months after birth, and medical, oral health, and periodontal status were assessed. In a multiplex immunoassay, 10 cytokines were simultaneously analyzed and cumulative Th1 and Th2 cytokine levels and Th1/Th2 ratio were calculated for all groups. Putative periodontal pathogens (n = 6) were evaluated by quantitative real-time polymerase chain reaction.

Results: Th2 cytokine levels were significantly lower (p = 0.014) while pro-inflammatory cytokine levels were significantly higher (p < 0.01) during pregnancy than postpartum. Similar Th1 levels were found between the groups (p = 0.143). Th1 and Th2 cytokines positively correlated with periodontal parameters (p < 0.001) and levels of studied bacteria during pregnancy (p < 0.05).

Conclusions: This study identified a significantly increased Th1/Th2 cytokine ratio during pregnancy and a positive association with putative periodontal pathogens. This immunological and microbiological deregulation in the oral milieu during pregnancy is suggestive of a destructive inflammatory periodontal profile.

Study registration: Clinical Trials.gov (Record BAP-2015).

Clinical relevance: Understanding altered oral immunological and microbiological regulation patterns during pregnancy may help improve the inflammatory periodontal profile in pregnant women.

Keywords: Cytokines; Oral immunity; Oral microbiota; Periodontal disease; Pregnancy; Saliva.

Fig. 1

Salivary biochemical findings in the pregnant (n = 96) and postpartum (n = 96) groups. A Th1 cytokine levels (IFN-γ, IL-2, TNF-α) (p = 0.14); B Th2 cytokine levels (IL-4, IL-5, IL-6, IL-10) (p = 0.015); C Th1/Th2 ratio (p = 0.0004); D proinflammatory cytokines (IL-1β, IL-8 levels) (p = 0.01). Median and IQR are given. *p < 0.05, **p < 0.001

Fig. 2

Microbiological findings in the pregnant (n = 96) and postpartum (n = 96) groups. A P. gingivalis (p = 0.0001), B T. denticola (p = 0.0001), C T. forsythia (p = 0.30), D C. rectus (p = 0.28), E P. intermedia (p = 0.0012), and F F. nucleatum (p = 0.0005). Median and IQR are given. *p < 0.05