Gestation is a challenge to haemostasis and it is associated with significant haemostatic changes. Several studies have evaluated von Willebrand factor in normal pregnancy, but none considered the personal history of bleeding. We studied a group of healthy non-bleeding women (184 pregnant, 64 puerperium, 37 non-pregnant) to evaluate normal ranges and their relationship to blood group and parity. The von Willebrand factor increased markedly from non-pregnant values up to the end of early puerperium (P < 0.0001), while factor VIII only showed a slight increase. Factor VIII and von Willebrand factor activity remained within the normal range for non-pregnant women. The return to non-pregnant factor levels occurred in late puerperium, later than previously reported. Only factor VIII was significantly lower in the O blood group (P = 0.035). As regards parity, there were no differences in factor VIII, von Willebrand factor antigen and von Willebrand factor ristocetin cofactor between primigravidae and multigravidae for any period studied (P = 0.888, 0.999, and 0.237, respectively). Our results provide reference ranges that may help to design a study in von Willebrand factor disease in pregnancy.
aNational Research Council (CONICET), Buenos Aires, bHaemostasis and Thrombosis Department, Haematological Research Institute, National Academy of Medicine, Buenos Aires, cObstetrics Department, Dr Cosme Argerich Hospital, Buenos Aires and dRene Baron Foundation, Buenos Aires, Argentina.
Sponsorship: This study was supported by grants from the René Barón Foundation and SECYT.
Correspondence and requests for reprints to Analía Sánchez-Luceros, MD, PhD, Haemostasis and Thrombosis Department, Haematological Research Institute, National Academy of Medicine, Buenos Aires. Pacheco de Melo 3081, 1425 Buenos Aires, Argentina. Tel/fax: +54 11 48050712; e-mail: firstname.lastname@example.org
Received 10 December 2002 Revised 20 March 2003 Accepted 22 March 2003