Analysis of risk factors and pregnancy outcomes in pregnant women with subchorionic hematoma

Subchorionic hemorrhage (SCH) or hematoma is one of the abnormal ultrasonic manifestations. At present, there are few studies on the pathogenesis of SCH, and its underlying mechanism is still unclear. It may be related to abnormal placenta formation and implantation, autoimmune dysfunction, and coagulation dysfunction. As a unique complication of pregnancy, SCH has a controversial effect on pregnancy outcome. The aim of the present study was to explore the possible etiology of SCH, especially its association with autoimmune dysfunctions, as well as the pregnancy outcomes of SCH patients. This retrospective cohort study was conducted at the Third Affiliated Hospital of Zhengzhou University. Patients with a singleton pregnancy of ≤14 weeks gestation from June 2021 to June 2022 were included. Patients with SCH detected by ultrasound were selected as the study group, while patients without SCH during the same period were chosen as the control group. Immunological indicators and pregnancy outcomes were primarily compared between the 2 groups. The decrease in protein S activity and antithrombin-III levels, the increase in homocysteine levels, and the presence of autoantibodies (such as lupus anticoagulant, anticardiolipin antibody, and antinuclear antibody spectrum) were found to be risk factors for SCH. SCH in the first trimester was associated with higher rates of premature rupture of membranes (13.5% vs 3.8%) and miscarriage (14.4% vs 6.4%). However, there were no significant differences in the rates of placental abruption, fetal distress, cesarean section, neonatal birth weight, and gestational age. The incidence of miscarriage was also significantly higher in patients with subchorionic hematoma (SCH) who tested positive for autoantibodies (28.2% vs 7.6%). There were no significant differences in other clinical characteristics and pregnancy outcomes between patients with SCH who had positive autoantibodies and those who did not. The occurrence of SCH may be related to maternal immune abnormalities. SCH may increase the risk of premature rupture of membranes and abortion. However, there is no correlation between the presence or absence of SCH and neonatal outcomes.