Pathogenetic significance of antiphospholipid antibodies in the development of placenta-associated complications in pregnant women with thrombocytopenia

BACKGROUND: Thrombocytopenia is one of the most common cytopenic syndromes that complicate pregnancy. It is considered a typical hematological criterion and the second most common manifestation of antiphospholipid syndrome. In recent years, the relationship between the development of thrombotic and placenta-associated pregnancy complications and the circulation of antiphospholipid antibodies has been actively studied, which makes it necessary to search for new methods for hemostasis correction and for prevention of the development of obstetric complications.

AIM: The aim of this study was to assess the incidence of antiphospholipid antibodies in pregnant women with thrombocytopenia in order to determine the risk of obstetric complications and adverse pregnancy outcomes depending on the presence of antiphospholipid antibodies in the examined women.

MATERIALS AND METHODS: 299 pregnant women were included in this multicenter prospective study: the main study group (n = 249) consisted of patients with thrombocytopenia, and the control group (n = 50) comprised women with normal platelet counts during a physiological pregnancy. All participants underwent a complete clinical and anamnestic examination and a study of the hemostasis system. To determine antibodies to cardiolipin, beta-2 glycoprotein 1, annexin V, and prothrombin (IgG/IgM/IgA), we performed enzyme-linked immunosorbent assay in 84 pregnant women with thrombocytopenia and in 25 women in the control group. Lupus anticoagulant was determined in 123 pregnant women of the main group and 25 women in the control group using an ACL-200 coagulometer (Instrumentation Laboratory, Spain).

RESULTS: A comparative analysis of antiphospholipid antibodies detection has shown that in pregnant women with thrombocytopenia, lupus anticoagulant was detected in every third case (35.8% of cases, 44/123 women), which is more common than in the control group (8.0% of cases, 2/25 women; p = 0.008). Antibodies to beta-2 glycoprotein 1 were detected in pregnant women with thrombocytopenia in every fourth case (27.4% of cases, 23/84 women), and in the control group only in 4% of cases (1/25 women; p = 0.013). Antibodies to cardiolipin were also more often detected in pregnant women with thrombocytopenia (23.8% of cases, 20/84 women) compared to the control group (4% of cases, 1/25 women; p = 0.040). Based on the data obtained with V Cramer, we established medium-strength direct correlations between criterial antiphospholipid antibodies circulation and the development of placenta-associated complications of pregnancy (p < 0.05; 0.2 < V < 0.4). We also identified statistically significant risks of developing placenta-associated complications in pregnant women with circulating antiphospholipid antibodies (95 % confidence interval excludes 1).

CONCLUSIONS: Thrombocytopenia during pregnancy develops more often in women with antiphospholipid antibodies. Antiphospholipid antibodies circulation elevates coagulation potential and activates intravascular coagulation, resulting in an increased risk of placenta-associated complications of pregnancy, which requires hemostasis correction.