Differences between the sexes in cord blood clotting factors

Sex-related differences are known to exist in the haemostatic variables of adults. In the present study, three clotting factors were measured in cord blood of 191 newborns. A sex-related difference was found for clotting factor VII, with higher plasma levels in female newborns (p < 0.01). Factor VIII:c also tended to be higher in female newborns, compared with male newborns (p = 0.07). No difference in fibrinogen concentrations was found. The observed difference between the sexes for clotting factor VII is not easy to understand, but it is in line with studies showing higher concentrations of factor VII in females than in males throughout adult life.