ACTIVATED PROTEIN-C SENSITIVITY RATIO IN PREGNANT-WOMEN AT DELIVERY

We studied activated protein C sensitivity ratio (APC-SR), factors V a nd VIII activity and von Willebrand antigen in control women, women us ing oral contraceptives, and pregnant women at delivery. The mean APC- SR of 2.4 in pregnant women was significantly lower than the mean APC- SR value of 3.5 for both the other groups and 45% of pregnant women ha d a ratio below the 5th percentile of the control group. None of them carried the R506-->Q mutation. This decreased ratio at delivery appear ed to be connected, at least in part, with increased VIII activity. Th us, APC-SR at delivery should not be used to detect APC resistance.