Complex formation of pregnancy-specific α2–glycoprotein (SP1α) and heparin

Summary. The Schwangerschaftsprotein 1 (SP₁,)α values in blood measured by rocket immunoelectrophoresis are affected by the addition of anticoagulants. When compared with values in serum, those in heparin plasma were much higher, while those in sequestrene ethylenediaminetetra acetic acid), sodium citrate and fluoride oxalate were lower. On the other hand, SP₁ and SP₁β concentrations were not significantly affected in heparin or sequestrene and were only slightly depressed in sodium citrate and flouride oxalate. The effect of heparin on SP₁α in serum was dosedependent. We surmise that SP₁α forms a complex with heparin and that it may be involved in the coagulation system in pregnancy.