[Prevention of vitamin K deficiency in the early neonatal period--prophylactic oral administration of VK to the mother].

We studied the effect of vitamin K(MK-4) on the prevention of vitamin K deficiency in the early neonatal period. MK-4 (20 mg/day) was given orally for 1-7 days to 183 pregnant women at 37-39 weeks gestation. In the MK-4 treated group, there were no cases of melena neonatorum but there were 9 cases in the untreated group (9/757, 1.2%). To investigate the influence of MK-4 administration on liver function and the VK dependent coagulation system, maternal and umbilical venous blood were taken to measure T-Bil, GOT, GPT, gamma-GTP, LDH, and II, VII, X activity and HPT. There was no significant difference between these values in MK-treated and untreated groups. MK-4 concentrations were measured in the maternal and umbilical venous blood of 68 subjects. The level of MK-4 in umbilical venous blood was less than 0.1 ng/ml in 17 of 21 subjects not treated with MK-4 but it was over 0.1 ng/ml in 30 of 47 MK-4 treated subjects. However, no MK-4 was detected in 6 of 8 subjects who were treated for 1 day. The level of MK-4 in maternal blood was less than 0.1 ng/ml in 12 of 21 untreated subjects but it was 0.19-92.6 ng/ml in all of the 47 MK-4 treated subjects. The mean MK-4 concentration in cord blood as a percentage of that in maternal blood was 17.9%. These findings indicate that MK-4 is effectively transported from maternal to fetal blood through the placenta and its administration to pregnant women is useful in preventing melena neonatorum.