Coagulation factors in the premature infant born after about 32 weeks of gestation.

In plasma samples from 10 premature infants born after about 32 weeks of gestation, a number of coagulation factors have been determined. For 9 infants, who were healthy, mean values are given: fibrinogen-antigen, 311 mg/dl; factor II, +/- 0.46 U/ml; factor V, 0.80 U/ml; factor VII, 0.59 U/ml; factor VIII coagulant activity, 0.93 U/ml; factor VIII-related antigen, 1.66 U/ml; procoagulant factor VIII antigen, 1.15 U/ml; factor IX coagulant activity, 0.41 U/ml; factor IX antigen, 0.42 U/ml; factor X coagulant activity, 0.52 U/ml; factor X antigen, 0.61 U/ml, and antithrombin III-antigen (AT-III), 0.43 U/ml. In 5 infants a second sample was taken a week after the first one; for most values there was no significant rise, except for factor II and AT-III. The values we found in this group of premature infants are within the range of those reported in earlier literature. They are higher than the ones we found in early fetal samples and most of them are similar to those we found in early fetal samples and most of them are similar to those we found in the cord blood of full-term newborns.