Periodontal Pathogens and Inflammatory Biomarkers in Missed Abortion

This observational case-control study will investigate whether periodontal infection and inflammation are associated with missed abortion in pregnancies without detected major fetal chromosomal abnormalities. A total of 160 pregnant women aged 18 to 40 years and at 20 weeks of gestation or earlier are planned to be enrolled. The study will include 80 women diagnosed with missed abortion and 80 women with an ongoing uncomplicated pregnancy matched according to age and gestational week. Participants will undergo a clinical periodontal examination, and unstimulated saliva samples will be collected. Saliva will be analyzed for selected periodontal bacteria, including Porphyromonas gingivalis, Fusobacterium nucleatum, and Tannerella forsythia, as well as inflammatory biomarkers. Serum obtained from blood samples already collected as part of routine obstetric care will be used to measure inflammatory biomarkers, including IL-1β, IL-6, TNF-α, CRP, MMP-8, and prostaglandin E2. No additional blood sample will be collected solely for this study. Routine complete blood count results will also be used to calculate systemic inflammatory indices. For participants with missed abortion, study samples and periodontal assessments will be obtained after the diagnosis has been confirmed and before uterine evacuation or medical treatment. Routine fetal genetic test results will be reviewed, and cases with detected chromosomal abnormalities included in the clinical genetic assessment will be excluded from the main analysis. The study aims to determine whether periodontal pathogen burden, periodontal disease, and local and systemic inflammatory responses differ between women with missed abortion and women with ongoing uncomplicated pregnancies.