This case control-study measures the levels of Interleukin-17 in gingival crevicular fluid and placental tissue samples of pregnant females as a possible marker in determining whether or not an association exists between chronic periodontitis and preterm labor. Interleukin-17 is a pro-inflammatory cytokine whose levels have been proven to increase in periodontal disease.

Inclusion Criteria:

1. Within the age range of 18-35 years
2. Free of any systemic diseases as referenced from Burket's Oral Medicine health history questionnaire (Glick2008)
3. Spontaneous normal term birth at ≥37 weeks of gestation without any obstetrical or medical complications
4. Spontaneous preterm birth (PTB) at <37 weeks of gestation after uterine contraction or rupture of membranes (Keelan1999)

Exclusion Criteria:

1. History of medications that may affect the study outcome, such as: current use of systemic corticosteroids or antibiotics for at least one month
2. Genital and urinary tract infections
3. Existing hypertension and diabetes mellitus before pregnancy, autoimmune disease, asthma, and chronic renal disease
4. Multiple pregnancies, cervical cerculage, abnormal placentation, past history of preterm delivery, or antepartum hemorrhage
5. Low or high maternal body mass index

Conducted in Cairo, Egypt at the Maternal-Fetal Medical Clinic at the Department of Obstetrics and Gynecology, Faculty of Medicine, Ain Shams University.