Risk Determinants of Arterial Thrombosis Increase the Risk of Intrauterine Growth Restriction (IGR)

Background: The HPA1-b allele of the beta3-subunit of the essential platelet integrin AlphaIIb-beta3 is a risk factor for increased platelet thrombogenicity, leading to arterial vascular occlusion also triggered by inflammatory endothelial alterations. We performed a case-control study to assess hereditary risk factor for arterial thrombosis in addition to the known risk determinants for venous thrombosis as risk determinants for fetal IGR.

Materials and Methods: 116 women with severe fetal IGR (defined by birth weight below the 5th-percentile for gestational age and sex) and 300 normal women were evaluated. Women with other reasons of IGR (history of venous thrombosis, fetal loss, and preeclampsia, neonatale immunthrombocytopenia) were excluded. The fetuses were born alive after the 24th week of gestation.

Results: A significant risk association could be shown for the HPA-1b/1b genotype OR 3.1 (95%CI 1.2–8.8), increased levels of lipoprotein (a) (>0.2g/l) OR 1.7 (95%CI 1.0–2.9), increased levels of fibrinogen (>median 284mg/dl) OR 2.8 (95%CI 1.8–4.4) increased levels of FVIII:C (>median 147%) OR 1.7 (95%CI 1.1–2.7), and increased levels of von-Willebrand-factor antigen (vWF-Ag) (>median) OR 2.7 (95%CI 1.1–2.7). The combination of risk determinants led to a further increase in risk (e.g. HPA-1b allele, increased lipoprotein (a) and vWF-Ag OR 14.0) There was no significant risk association for factor V Leiden G1691A OR 1.3 (95% CI 0.7–2.81), and prothrombin G20210A mutation. OR 2.0 (95% CI 0.6–6.5)

Conclusions: Increased platelet thrombogenicity via interaction with an inflammatory vascular process and/or via plasma levels of components of hemostasis/receptor ligands appear to be more important in women with IGR than the established risk determinants for venous thrombosis.