Objective To assess the obstetric outcome in women with von Willebrand's disease or factor XI deficiency.

Setting Haemophilia Centre and Haemostasis Unit, The Royal Free Hospital.

Population Women with von Willebrand's disease (n= 31) and with factor XI deficiency (n= 11) registered at the Royal Free Hospital Haemophilia Centre who had had a pregnancy within the previous 17 years (1980–1996), including 84 in women with von Willebrand's disease and 28 in women with factor XI deficiency.

Methods Women were interviewed and details of the obstetric history were obtained. The records of the Haemophilia Centre and the women's maternity records were also reviewed.

Results Threatened miscarriage occurred in 33% and 14% of pregnancies with von Willebrand's disease and factor XI deficiency, respectively. Excluding recurrent miscarriages, 14/68 (21%) of pregnancies with von Willebrand's disease and one pregnancy with factor XI deficiency miscarried spontaneously. There was an increased incidence of primary and secondary post-abortal bleeding complications. Factor VIJI and von Willebrand factor antigen and activity levels increased significantly in pregnancy in all women apart from those with severe von Willebrand's disease. Factor XI, however, did not show any significant change. No neonatal haemorrhagic complications in association with the birth process were reported, although ventouse and difficult forceps deliveries were avoided. Extensive perineal bruising and haematoma was reported in three women with von Willebrand's disease; two of these were associated with forceps delivery. The incidence of primary postpartum haemorrhage was 185% in von Willebrand's disease and 16% in factor XI deficiency. Blood transfusion was required in six cases of von Willebrand's disease and two cases of factor XI deficiency. Ten of fourteen instances of primary postpartum haemorrhage occurred when maternal factor levels were < 50 IU/dL with no prophylactic treatment for labour. The incidence of secondary postpartum haemorrhage was 20% in von Willebrand's disease and 24% in factor XI deficiency. None of the women who had prophylactic treatment during labour or the puerperium suffered any significant bleeding complications. There were three neonatal bleeding complications.

Conclusion Pregnancy, labour and the puerperium are associated with significant bleeding problems in women with von Willebrand's disease or factor XI deficiency, but these are largely preventable. Specialist obstetric care in close liaison with the haemophilia centre is essential to minimise maternal deficiency. and neonatal complications.