(1206) Is first trimester hemorrhage with concurrent anemia associated with placenta accreta spectrum?

Objective: First trimester hemorrhage may contribute to abnormal placentation. These abnormalities can have devastating consequences in the form of placenta accreta spectrum (PAS), which is associated with significant maternal morbidity and mortality. Subchorionic hematoma, a leading cause of first trimester hemorrhage, and anemia may contribute to placental hypoxia and aberrant placentation. We sought to establish if an association exists between anemia, hemorrhage, and PAS.

Study Design: his is a secondary analysis of a retrospective case-control study using patient data from 2007 to 2022 at a large tertiary care center. Demographics and clinical characteristics of patients with and without PAS (diagnosed by histopathology or high index of clinical suspicion) were collected as well as complete blood count in early pregnancy. Bivariate analyses compared baseline case and control characteristics. Logistic regression was performed to assess risk of PAS according to the presence of first trimester hemorrhage with concurrent anemia (hemoglobin < 11 g/dL) while adjusting for relevant covariates.

Results: The final cohort included 88 patients with confirmed PAS and 27,126 controls. Rates of first trimester hemorrhage alone were not significantly different between groups (12.3% of those without PAS versus 17.0% of those with PAS, p = 0.2); however, those with PAS were more likely to have first trimester hemorrhage and concurrent anemia (0.4% of those without PAS versus 5.7% of those with PAS, p < 0.001). In multivariate logistic regression, first trimester hemorrhage and concurrent anemia was associated with higher odds of PAS than any other covariate, including prior cesarean or placenta previa (adjusted odds ratio = 16.6, 95% confidence interval 5.58 - 39.7).

Conclusion: Patients with a first trimester hemorrhage and concurrent anemia have 16-fold higher odds of PAS. This suggests that early pregnancy placental disruptions may significantly increase the risk for PAS. Further research into the pathophysiology of this process is warranted to fully understand this phenomenon.