Objective: To determine whether placental abruption is associated with an increased incidence of histologic chorioamnionitis among singleton gestations in both term and preterm births and whether this association is dependent on the  severity of histologic chorioamnionitis.Pateints and patients : A prospective case- control study was conducted at Al-Yarmouk Teaching Hospital, Department of Obstetrics and Gynecology from 2018 to 2020.this Study  included 72 singleton pregnant  women with clinical and / or sonographic diagnosis of placental abruption,  44 cases were preterm gestations and 28 were term gestations and  their matched controls, who all attended the labor ward in Al-Yarmouk Teaching Hospital, Department of Obstetrics and Gynecology  during  the study period. After delivery, all study population were submitted for histologic examination of their placentae. Each placenta was reviewed for gross findings and histologic evidence of chorioamnionitis. The degree of chorioamniontis is then sub classified into mild, moderate or severe. The association between histologic chorioamnionitis and placental abruption were analyzed in all groups. Results: Histological chorioamnionitis were more common in abruption cases than controls in both preterm and term groups, among preterm abruption cases chorioamnionitis was present in 70.4% versus 25% of controls. At term gestations the corresponding rates were 64.3% and 35.7% respectively. Severe histological chorioamnionitis was 7.62 times more common in preterm abruption cases than controls but it did not reach statistical significance, while mild, and moderate chorioamnionitis were statistically significant, OR 6.35, 95% CI (1.79-23.95), OR 8.25, 95% CI (1.99-39.81) respectively. Conclusion: Histologic chorioamnionitis is associated with placental abruption. The association   is   strongest in the presence of severe chorioamnionitis at preterm and, to a lesser extent, at term gestations.

Keywords: Histologic chorioamnionitis; Placental Inflammation; Risk of Placental Abruption and  Preterm Gestations