Histopatología de la placenta en la rotura prematura de membranas de pretérmino: relación con la microbiología aislada y con los resultados maternoneonatales / Placental pathology in premature rupture of membranes: its relationship with microbiologícal findings, maternal and neonatal outcome

ABSTRACT

Background: There is a close relationship between premature membrane rupture, bacterial infections and premature labor. Aim: To study placental histological changes in patients with preterm membrane rupture. To establish a relationship between pathological findings, amniotic fluid and lower genital tract microbiological studies, maternal and neonatal outcome. Patients and methods: Patients with premature membrane rupture of membranes between 24 and 34 weeks of gestation participated in this study. On admission, patients had no evidence of clinical chorioamnionitis, labor or fetal distress. Microbiological studies of the amniotic fluid and cervicovaginal secretions were performed and the placenta was sent for pathological study. Results: Seventy one placentas were available for the study. The main pathological findings were acute chorioamnionitis in 58 percent, trophoblastic proliferation in 38 percent, funisitis in 37 percent, villitis in 16 percent, fetal vascular lesions in 14 percent and no findings in 17 percent. Microbial invasion of amniotic cavity was present in 89 percent of acute chorioamnionitis. Sixty one percent of trophoblastic proliferation and all fetal vascular lesions were associated with negative amniotic and cervical cultures. Newborns with acute funisitis had a higher frequency of neonatal death (29 percent), severe asphyxia (42 percent) and neonatal infections (29 percent). Conclusions: Acute chorioamnionitis is the most frequent finding in patients with preterm membrane rupture and microbial invasion of amniotic cavity. In the absence of intra amniotic infection, proliferation of the trophoblast and the presence of fetal vascular lesions predominate. Acute funisitis is strongly associated with adverse fetal outcome