Activated protein C resistance in normal and pre-eclamptic pregnancies.
OBJECTIVE
A lower ratio in the classic activated protein C resistance (APC-R) test has been reported during pregnancy, which has been called 'acquired' APC-R. However, little is known about the cause of the lowered ratio, and whether or not there is a correlation with blood coagulation activation. The primary objective of our study was to determine changes in APC-R levels in each of the trimesters of normal pregnancy. The secondary objective was to confirm whether APC-R levels were lower in pregnancies complicated by pre-eclampsia than in a control group. Finally, this prospective study was performed to investigate the prevalence of APC-R among pregnant women and to elucidate its obstetric consequences.


METHODS
We enrolled 35 healthy pregnant women and 47 pregnant women affected by pre-eclampsia in our study. The following laboratory tests were performed: prothrombin time, partial thromboplastin time, fibrinogen levels, antithrombin III, plasmatic fibronectin (as a marker of endothelial damage), haptoglobin (as a marker of intravascular haemolysis), a functional test for APC-R and analysis of factor V Leiden mutation by polymerase chain reaction.


RESULTS
The activated protein C sensitivity ratio was lower in the pathological group than in the control group (p = 0.008 and p = 0.02, respectively). Plasmatic fibronectin was found to be higher in the pathological group than in the control group (p = 0.05). Finally, the overall prevalence of factor V Leiden mutation was 5.4%, i.e. 2/35 women (5.7%) in the control group and 3/47 women in the pathological group (6.38%).


CONCLUSIONS
The APC ratio decreased after 20 weeks of gestation until week 42. This decrease was most pronounced in the third trimester, in which resistance was demonstrated in 34.2% of control group patients. In pre-eclampsia, we found a greater reduction of the APC ratio than in controls. We hypothesise that this is due to a decrease in the plasmatic levels of coagulation inhibitors and an increase in coagulatory factors.
Paternoster
D M
DM
Department of Obstetrics and Gynecology, Padova University, Padova, Italy. paternod@unipd.it
Stella
A
A
Simioni
P
P
Girolami
A
A
Snijders
D
D
D020016:Activated Protein C Resistance / Q000097:blood / Q000453:epidemiology* / Q000235:genetics; D000328:Adult; D000990:Antithrombin III; D016022:Case-Control Studies; D005165:Factor V / Q000235:genetics*; D005260:Female; D005340:Fibrinogen; D005353:Fibronectins / Q000097:blood; D006242:Haptoglobins; D006801:Humans; D007558:Italy / Q000453:epidemiology; D010314:Partial Thromboplastin Time; D016133:Polymerase Chain Reaction; D011225:Pre-Eclampsia / Q000097:blood*; D011247:Pregnancy / Q000097:blood*; D011264:Pregnancy Trimesters; D011296:Prenatal Diagnosis; D015995:Prevalence; D011446:Prospective Studies; D011517:Prothrombin Time
D005353:Fibronectins; D006242:Haptoglobins; C095381:factor V Leiden; D000990:Antithrombin III; D005165:Factor V; D005340:Fibrinogen