Maternal antenatal administration of vitamin K1 results in increasing the activities of vitamin K-dependent coagulation factors in umbilical blood and in decreasing the incidence rate of periventricular-intraventricular hemorrhage in premature infants

Abstract

Aims: Infants less than 35 weeks' gestation age are susceptible to periventricular-intraventricular hemorrhage (PIVH). This may be partially attributable to low concentrations of vitamin K-dependent coagulation factors. The purposes of this study were: (1) to determine the umbilical blood activity levels of vitamin K-dependent coagulation factors II, VII, IX and X; (2) to investigate the change in activities of these factors in premature infants' umbilical blood after prenatal administration of vitamin K1 to the mothers; and (3) to study the prophylactic effects on PIVH after maternal antenatal supplemental vitamin K1.

Methods: Pregnant women in preterm labor at less than 35 weeks of gestation were randomly selected to receive antenatal vitamin K1 10 mg per day injection intramuscularly or intravenously for 2-7 days (vitamin K1 group, n = 40), or no such treatment (control group, n = 50). At the same period, cord blood samples were collected from thirty full-term neonates to compare the factor levels with those of premature infants. Intracranial ultrasound was performed by the same sonographer to determine the presence and severity of PIVH.

Results: The activities of vitamin K-dependent coagulation factors in umbilical blood in the control group were: factor II 25.64+/-9.49%, factor VII 59.00+/-17.66%, factor IX 24.67+/-8.88%, and factor X 30.16+/-5.02%. In full-term infants, the respective values were: factor II 36.70+/-4.88%, factor VII 64.54+/-10.62%, factor IX 30.18+/-5.69%, and factor X 34.32+/-12.63%. In vitamin K1 group these factors were: factor II 36.35+/-6.88%, factor VII 69.59+/-16.55%, factor IX 25.71+/-10.88%, and factor X 39.26+/-8.02%. The data suggest the absence of vitamin K-dependent coagulation factors in preterm infants, and antenatal supplement of vitamin K1 may increase the cord blood activity of factor II, VII and factor X (P < 0.001). In addition, the overall rates of PIVH in the vitamin K1 group and in controls were 32.4 and 52.0%, respectively (P = 0.036), and the frequency of severe PIVH was 5.0 and 20.0%, respectively (P = 0.038).

Conclusions: Administration of vitamin K1 to pregnant women at less than 35 weeks' gestation age may result in improved coagulation and may reduce the incidence as well as the severity degree of PIVH.