Influence of hemostatic factors on spontaneous abortion.

To assess the relationship between hemostatic factors and spontaneous abortion, 134 pregnant women presenting to the emergency department were recruited and followed through 22 weeks' gestation. Cases were women experiencing a spontaneous abortion and controls were women who maintained their pregnancy. Fibrinogen, factor VII antigen, activated protein C-sensitivity ratio (APC-SR), protein S, and plasmin-antiplasmin (PAP) were measured. Cases had lower mean levels of fibrinogen and factor VII antigen compared with controls (3.1 g/L vs. 3.7 g/L and 89% of normal vs. 109% of normal, respectively). Regression analyses found that women with fibrinogen levels below 3.0 g/L had a five-fold increased risk of spontaneous abortion (OR = 5.1, 95% CI: 1.8-14.4) and women with factor VII antigen levels below 94% of normal had a threefold increased risk of spontaneous abortion normal (OR = 3.3, 95% CI: 1.2-8.5). Similar mean levels of APC-SR, protein S, and PAP were found in the two groups.