[Profile of Von Willebrand factor antigen in pregnancy: descriptive study of 390 pregnant women in Morocco].

Von Willebrand factor (vWF) is a glycoprotein which plays an important role in hemostasis. Its quantitative or qualitative deficit results in von Willebrand's disease (vWD). The study aims to update the current understanding of the distribution of vWF rates in Moroccan pregnant women and their variability in function of the ABO blood group. We conducted a cross-sectional study of 390 pregnant women from the Rabat-Salé-Kenitra region. Sample size was calculated on the basis of a prevalence of 1%, corresponding to the global prevalence of vWD with a margin of error of 5% and a confidence level of 95%. There were 317 cases (81.28%) of elevated vWF levels (> 160%) out 390 pregnant women. The levels of factor VIII (FVIII) varied in parallel in a significant way (p < 0.001) with the levels of vWF (Pearson's r 0,597). The distribution of the ABO blood groups has had an influence on the level of vWF with a significant difference (p < 0.001) between the four groups: the lowest average level in the group O (188,54±57,02), followed by group A (203,19±54,46), then group AB (219±38,95) and finally group B (221,15±48,63). Our results confirm on the one hand an elevation of the levels of vWF during pregnancy and on the other hand the influence of ABO blood group on the levels of vWF.