The Relationship Between Maternal Periodontal Inflammation and Pregnancy Outcomes: Evaluation Using Inflammatory and Oxidative Stress Biomarkers in Saliva and Amniotic Fluid

This prospective observational cohort study will be conducted at the Department of Obstetrics and Gynecology and the Department of Periodontology, Gülhane Training and Research Hospital, Health Sciences University, Ankara, Türkiye. The study is designed to investigate the association between maternal periodontal inflammation and inflammatory and oxidative stress biomarkers measured in saliva and amniotic fluid, and to evaluate their relationship with pregnancy outcomes.

A total of 80 pregnant women between 28 and 32 weeks of gestation will be recruited consecutively from the Obstetrics and Gynecology outpatient clinic. The required sample size was determined using G*Power version 3.1 based on the primary outcome variable (difference in amniotic fluid 8-hydroxy-2'-deoxyguanosine [8-OHdG] levels between women with and without periodontitis). Assuming an effect size (Cohen's d) of 0.70, a two-sided significance level (α = 0.05), and a statistical power of 85% (1-β = 0.85), the minimum required sample size was calculated as 76 participants. To account for potential dropouts, incomplete biological samples, and missing clinical data, the final recruitment target was increased to 80 participants.

Eligible participants will be women aged 18-40 years with singleton pregnancies between 28 and 32 gestational weeks, who are systemically healthy, have undergone routine gestational diabetes screening with normal results, are not receiving medications other than routine prenatal vitamin and iron supplementation, have not received periodontal therapy within the previous six months, and are classified as low-risk pregnancies. Women with multiple pregnancies, smoking or alcohol consumption, acute infections, antibiotic or anti-inflammatory drug use during pregnancy, placental pathology, major fetal anomalies, previous chorioamnionitis, or other obstetric high-risk conditions will be excluded.

All participants will receive detailed verbal and written information regarding the study, and written informed consent will be obtained before enrollment. The study involves no experimental intervention, and all clinical procedures will be performed in accordance with routine clinical practice.

Following enrollment, participants will be referred to the Department of Periodontology for a comprehensive periodontal examination. Clinical periodontal parameters will be recorded by a calibrated periodontist using a manual periodontal probe and will include Plaque Index (PI), Gingival Index (GI), Bleeding on Probing (BOP), Probing Pocket Depth (PPD), and Clinical Attachment Level (CAL). The diagnosis of periodontitis will be established according to the 2017 World Workshop Classification of Periodontal and Peri-Implant Diseases and Conditions.