Introduction: Preterm labor (PTL) is an important obstetric intercurrence that affects 5 to 10% of pregnancies. Among the known factors of PTL etiology are PTL occurrence in previous pregnancies, multiple pregnancies, polyhydramnios, vaginal bleeding during pregnancy, premature membrane rupture (PMR) and bacterial vaginosis. Despite the advancement achieved in Neonatology, morbidity and mortality resulting from high rates of preterm births have remained constant in the last few decades. Objective: This study aims at evaluating maternal and perinatal outcomes of pregnant women with a history of preterm labor in previous pregnancies and submitted to active search for vaginal infection. Material and Method: It is a prospective-cohort epidemiological study to be conducted in Botucatu/SP. Two study groups (G1 and G2) will be formed, and each of them will comprise 140 pregnant women with a history of preterm childbirth. G1 will be related to the active search and etiological diagnosis of lower genital tract infections, and G2 will be related to non-search for such infections, for which the routine care protocol of primary health units in the city of Botucatu will be maintained. Care propedeutics for the pregnant women (G1) will include the performance of direct examination of vaginal content stained by the Gram method, culture in Diamonds medium, polymerase chain reaction (PCR) of endocervical secretion collected in the primary health care services in the city at two moments: prior to the 20th gestational week (M1) and at the 36th week (M2). Moment M3 will take place after childbirth for evaluation of the perinatal outcome.

Inclusion Criteria:

• Will be included in the study women with a history of preterm labor in previous pregnancy, without other risk factors identified in the initial prenatal current to initiate prenatal care until 20 weeks of gestation in any unit of primary care and Botucatu they have agreed to participate.

Exclusion Criteria:

• Will be excluded from the study women who have complications during pregnancy such as urinary tract infections, severe periodontal disease, hypertension, diabetes or multiple gestation, among others.