Pregnancy outcome in Factor XI deficiency: incidence of miscarriage, antenatal and postnatal haemorrhage in 33 women with Factor XI deficiency

Pregnancy complications in women with Factor XI deficiency were assessed in this retrospective analysis. All nonnulliparous women registered with Factor XI deficiency in the East Midlands region were included. Each woman was classified into 'bleeder' or 'nonbleeder'. Rates of antenatal and postnatal bleeding and miscarriage rate were recorded. A total of 33 women had 105 pregnancies. Pregnancy and delivery was uneventful in 70% of the cases. Postpartum haemorrhage (PPH) appears increased in women with a 'bleeding' phenotype with a highly significant difference between 'bleeders' and 'nonbleeders' (relative risk [RR] 7.2; CI 1.99-25.9). Miscarriage rate appeared unchanged. We conclude that PPH is increased in a subgroup with a bleeding phenotype. Larger studies are needed to define the underlying factors.