Preterm birth is the main contributor to perinatal morbidity/mortality and high costs associated to stays in neonatal intensive care units. Its frequency has increased especially by ascending bacterial infection. Antibiotic treatment in preterm birth symptoms with intact membranes has not shown benefits and associated to its use is the neurological disabilities found in children whose mothers received antibiotics. However another study showed benefits of the treatment with antibiotics in patients with endocervical inflammation, but without microbial invasion of the amniotic cavity. Further studies are needed to clarify the benefit of antibiotics in preterm birth with intact membranes with these conditions.