Response to activated protein C decreases throughout pregnancy.
BACKGROUND
The possibility that changes in activated protein C anticoagulant activity may contribute to the hemostatic changes associated with pregnancy has been previously investigated, but the results of the studies are still controversial.


METHODS
Nine hundred and sixty-one healthy nonpregnant and 711 normal pregnant women who were noncarriers of factor V Leiden at different weeks' gestation were included in a cross-sectional trial. Moreover, the APC ratio was repeatedly measured in 45 women throughout pregnancy. The activated protein C ratio was tested using the modified activated partial thromboplastin time-based assay.


RESULTS
A significantly lower APC ratio was observed at 20-28 and 32-38 (p = 0.0001) weeks' gestation compared with nonpregnant values. The decrease in the APC ratio throughout pregnancy showed a significant trend (p = 0.014). In none of the subjects did the APC ratio reach the cut-off values for APC resistance.


CONCLUSIONS
Our data confirm a reduction in the APC ratio throughout pregnancy. In our series, an APC ratio of less than 2.0 according to the cut-off point of our laboratory).
Benedetto
Chiara
C
Department of Gynecology and Obstetrics, University Hospital, University of Turin, Italy. chbened@tin.it
Marozio
Luca
L
Tavella
Anna Maria
AM
Maulà
Vincenza
V
Carmignani
Daniela
D
Curti
Antonella
A
D020016:Activated Protein C Resistance / Q000097:blood; D000328:Adult; D016022:Case-Control Studies; D003430:Cross-Sectional Studies; D005260:Female; D005865:Gestational Age; D006801:Humans; D011247:Pregnancy / Q000097:blood*; D011250:Pregnancy Complications, Hematologic / Q000097:blood; D011486:Protein C / Q000378:metabolism*
D011486:Protein C