Significant association between circumvallate placenta, placental abruption and acute chorioamnionitis in preterm birth: A 23-year retrospective cohort study

Aim: circumvallate placenta, placental abruption and acute chorioamnionitis separately are associated with unfavourable clinical outcomes. We aimed to determine the prevalence and define whether an association exists between the three abnormalities. Methods: 16,042 placenta pathology reports between 1997 and 2020 from a tertiary care centre in the Netherlands were retrospectively analysed. For the statistical analysis, the chi-square test and bootstrapping were used to evaluate an association. Results: In our cohort the prevalence of circumvallate placenta is 2.2 %, placental abruption cases 4.0 % and acute chorioamnionitis 20.6 %. We observed a statistically significant association between all three placental abnormalities: circumvallate placenta, placental abruption and acute chorioamnionitis. In addition, there was also an association between circumvallate placenta and acute chorioamnionitis. Conclusion: Our results show that combined presence of circumvallate placenta, placental abruption and acute chorioamnionitis are associated in preterm birth (p = 0.001). A remarkable finding is that the combination of all three abnormalities (circumvallate placenta, placental abruption and acute chorioamnionitis) was not observed in term pregnancies >37 weeks.