The goal of a new study published in the Journal of Investigative and Clinical Dentistry was to establish the association between the presence of oral and uro-vaginal microorganisms in the placental membrane and preterm delivery (PTD), the premature rupture of membranes (PRM), and the clinical signs of intra-amniotic infection. In this study, 84 women with PTD and 127 women with delivery at term were assessed for the PRM, clinical signs of intra-amniotic infection, and the presence of periodontitis. The results identified 27 microorganisms in the placental tissue using nested polymerase chain reaction (PCR). Porphyromonas gingivalis (P. gingivalis) was quantified by droplet digital PCR. The prevalence of microorganisms was found to be 9.47%; P. gingivalis was the most prevalent – 5.68%. The results showed that Mycoplasma hominis, Ureaplasma urealyticum, Staphylococcus spp, and Fusobacterium nucleatum were isolated at a very low frequency in the placenta. On the other hand, Candida albicans was associated with PTD. Periodontitis was associated with clinical signs of infection and with PTD. The results indicated that the presence of P. gingivalis in the placenta was not associated with perinatal complications. Thus, it was stated that detecting microorganisms in the placenta by nested PCR is not relevant as it has a poor association with clinical variables that establish the diagnosis of chorioamnionitis. Nevertheless, periodontitis was associated with the clinical signs of intra-amniotic infection and PTD.