The effect of maternal thrombophilia on placental abruption: Histologic correlates

Objective. To determine if the histology of placental abruption differs by maternal thrombophilia status. Study design. This was a multicentre, case-control study of women with abruption and delivering at 20 weeks' gestation, collected as part of the ongoing New Jersey-placental abruption study. Women were identified by clinical criteria of abruption. Maternal blood was collected postpartum and tested for anticardiolipin antibodies, and mutations in the Factor V Leiden and prothrombin genes. Cases were comprised of women with an abruption and a positive thrombophilia screen. Controls were comprised of women with an abruption and a negative thrombophilia screen. All placental histology was systematically reviewed by two perinatal pathologists, blinded to the abruption status. Results. A total of 135 women with placental abruption were identified, of which 63.0% (n=85) had at least one diagnosed maternal thrombophilia. There were increases in the rates of meconium-stained membranes (7.9%vs. 2.1%, p=0.015) and decidual necrosis (4.5%vs. 2.1%, p=0.023) when a maternal thrombophilia was diagnosed. Although there was no difference in the overall presence of infarcts between the two groups (27.0%vs. 38.3%, p=0.064), the presence of an old infarct was more common among women with a positive thrombophilia screen (83.3%vs. 44.4%, p=0.003). Conclusion. Placental abruption with a positive maternal thrombophilia screen is associated with higher rates of old placental infarcts and decidual necrosis compared with abruption when thrombophilia is not diagnosed. These lesions suggest a chronic etiology of placental abruption in the presence of a maternal thrombophilia.