Activated protein C sensitivity, protein C, protein S and coagulation in normal pregnancy

Thromb Haemost. 1998 Jun;79(6):1166-70.


A prospective study of activated protein C sensitivity, protein C, protein S, and other coagulation factors in 239 women during normal pregnancy was carried out. Protein C activity appeared unaffected by gestation, although an elevation of protein C activity was observed in the early puerperium. A fall in total and free protein S with increasing gestation was observed. Activated protein C sensitivity ratio (APC:SR) showed a progressive fall through pregnancy. This fall correlated with changes in factor VIIIc, factor Vc and protein S. 38% of subjects, with no evidence of Factor V Leiden or anticardiolipin antibodies, showed a low APC:SR (APC:SR <2.6) in the third trimester of pregnancy. Aside from a significant reduction in birth weight, no difference in pregnancy outcome was observed between these subjects and those with a normal APC:SR. Activated protein C sensitivity ratio, modified by pre-dilution of patient samples with factor V depleted plasma, showed no consistent trend with gestation.

MeSH terms

  • Birth Weight
  • Blood Coagulation / physiology*
  • Blood Coagulation Tests
  • Blood Pressure
  • Blood Proteins / analysis
  • Cross-Sectional Studies
  • Factor V / genetics
  • Female
  • Heterozygote
  • Humans
  • Infant, Newborn
  • Postpartum Period
  • Pregnancy / blood*
  • Pregnancy Outcome
  • Pregnancy Trimesters
  • Prospective Studies
  • Protein C / physiology*
  • Protein S / physiology*
  • Reference Values
  • Scotland


  • Blood Proteins
  • Protein C
  • Protein S
  • factor V Leiden
  • Factor V