The effect of protamine on serum levels of placental protein 5 (PP5) in normal and abnormal pregnancy: a possible relation to coagulation abnormalities.

The levels of placental protein 5 (PP5) in pregnancy serum show an apparent increase after the addition of protamine sulphate. The difference of the apparent concentrations of serum PP5 in the presence and absence of protamine (delta PP5) was determined in 345 normal and abnormal pregnancies. A positive delta PP5 was less frequent in diabetic pregnancy (45 per cent) and pre-eclampsia (57 per cent) than in normal pregnancy (80 per cent). These findings provide further evidence that PP5 may be involved in the coagulation system, and in particular may relate to abnormal coagulation processes at the placental site.