Are antibiotics useful in patients with preterm and spontaneous labor, intact membranes and ascendant bacterial infection? A narrative review

Preterm labor (PL) is the leading cause of perinatal morbidity/ mortality and is frequently spontaneous with intact membranes (IM). Intrauterine infection is its most common cause in a public hospital in Chile. There is evidence that ascending bacterial infection from the vagina is responsible for intraamniotic infection/inflammation, PL, and adverse maternal and perinatal outcomes. This narrative review includes randomized controlled trials (RCTs), published in PubMed, Cochrane, Embase, Scielo, Science Direct, Wiley Online Library on the mechanisms involved in the rise of vaginal infection, the infec-tious factors involved in adverse maternal-perinatal outcomes, and the efficacy of antibiotics in these cases. They do not recommend the use of prophylactic antibiotics because they cause short and long-term damage to children. But this result is biased because the presence of subclinical infection/inflammation was not evaluated, which lowers the degree of recommendation. There are also RCTs that eradicate intra-amniotic infection/inflammation, reduce neonatal morbidity/ mortality, but they are isolated studies, obtained from subanalyses, with a low level of evidence. Systematic reviews and meta-analyses of RCTs with subclinical infection/inflammation study are required to assess whether antibiotics are useful in spontaneous PL with IM.