The aim of this study is to evaluate the effects of treatment of periodontal disease during the second trimester of gestation in adverse pregnancy outcomes.

Pregnant patients during the 1st and 2nd trimesters at antenatal care in a Public Health Center will be divided into two groups: NIG- 'no intervention' or IG- 'intervention,' according to agreement in receive periodontal treatment during pregnancy. Treatment will be performed by a single periodontist consisting of scaling and root planning (SRP), professional prophylaxis (PROPH) and oral hygiene instruction (OHI). Patients at NIG will receive PROPH and OHI during pregnancy and will be referred for treatment after delivery. Periodontal evaluation will be performed by a single trained examiner, blinded to periodontal treatment, according to probing depth (PD), clinical attachment level (CAL), plaque index (PI) and sulcular bleeding index (SBI) at baseline and 35 gestational weeks-28 days post-partum. Primary adverse pregnancy outcomes to be addressed are: preterm birth (< 37 weeks), low birth weight (< 2.500 Kg), late abortion (14-24 weeks) or abortion (< 14 weeks). The results obtained will be statistically evaluated according to OR, unpaired t test and paired t test.

It is expected that periodontal treatment during the second trimester of gestation will result in decreased rates of adverse pregnancy outcomes.

All patients entering the study at the 1st and 2nd trimesters will be invited to participate in an oral health program, including oral hygiene instruction, caries diagnosis and treatment, and evaluation and treatment of periodontal conditions during the second trimester. Those who refuse to receive periodontal treatment during pregnancy will constitute the 'no intervention' control group (NIG), while those who agree in receiving dental and periodontal treatment during the second trimester of gestation will constitute the 'intervention' group (IG).

Patients are going to be evaluated by a single calibrated periodontist blinded in relation to periodontal treatment, which will be performed by another periodontist. Treatment consists of scaling and root planning, professional prophylaxis and oral hygiene instruction. Obstetrical data, birth weight and gestation duration will be recorded after examination and recording by the responsible obstetrician and nursery staff.

Inclusion Criteria:

• confirmed singleton gestations
• pregnancy of 9-24
• systemically healthy women
• age range: 16-39 years old

Exclusion Criteria:

• non confirmed pregnancy
• age inferior to 16 years or superior to 39 years
• multiple gestations
• smoking
• alcohol or drugs abuse
• history of congenital heart disease
• current use of corticosteroids or antibiotics
• presence of systemic conditions (eg: diabetes, hypertension, or genitor-urinary infections)