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 >or=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.