Information on the effect of pregnancy or oral contraceptives (OC) in congenital factor V (FV) deficiency is scanty. The personal investigation of five homozygous and 17 female heterozygous showed that patients with severe deficiency bleed considerably at the time of delivery. However, bleeding can be controlled properly by administration of fresh frozen plasma with excellent foetal outcome. The safe level for adequate haemostasis seems around 25% of normal. On the contrary, heterozygote patients show no significant postpartum bleeding and therefore need no substitution therapy. Oral contraceptives were taken and well tolerated by four of our homozygous patients and appear to be beneficial because they cause a decrease in menometrorrhagies thereby improving the anaemia and decreasing transfusional needs. One patient took hormonal replacement therapy with no undue effects. No thrombosis was noted in the propositae during oral contraceptive therapy. The review of the literature has allowed the gathering of information on 20 additional pregnancies. The foetal outcome was satisfactory in every instance. Excessive bleeding was noted in 11 pregnancies. In seven of the remaining pregnancies, no undue bleeding was noted thanks to appropriate substitution therapy. In the remaining two pregnancies no bleeding was noted and no substitution therapy was given. No data are apparently available in the literature about the use of OCs in FV deficiency.