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Published on: December 31, 2015
Vitamin K status of premature infants: implications for current recommendations
D Kumar1, F R Greer, D M Super
1Department of Pediatrics, MetroHealth Medical Center, Case Western Reserve University, Cleveland, Ohio 44109, USA. dkumar@metrohealth.org
Insights
Premature infants show high vitamin K levels initially due to supplementation, which normalize by 40 weeks postconception. Protein-induced in vitamin K absence (PIVKA II) was undetectable, indicating adequate vitamin K status.
Area of Science:
- Neonatal Medicine
- Pediatric Nutrition
- Biochemistry
Background:
- Newborn infants are susceptible to vitamin K deficiency.
- Vitamin K status in term infants is well-documented, but data for premature infants is limited.
- Understanding vitamin K status in premature infants is crucial for appropriate supplementation strategies.
Purpose of the Study:
- To assess vitamin K status in premature infants from birth to 40 weeks' postconceptional age.
- To measure plasma vitamin K and protein-induced in vitamin K absence (PIVKA II) levels.
- To evaluate the impact of different feeding methods on vitamin K status.
Main Methods:
- Premature infants (
- All infants received 1 mg intramuscular vitamin K at birth, followed by daily supplementation via total parenteral nutrition (TPN).
- Plasma vitamin K and PIVKA II were measured at birth, 2, 6 weeks, and 40 weeks' postconception.
Main Results:
- At 2 weeks, plasma vitamin K levels were highest in the most premature group (
- By 40 weeks' postconception, vitamin K intake and plasma levels normalized and were similar across all groups.
- No detectable PIVKA II was found in any postnatal plasma samples, indicating adequate vitamin K status.
Conclusions:
- Premature infants exhibit high plasma vitamin K levels early in life due to parenteral supplementation.
- Vitamin K status, as indicated by undetectable PIVKA II, is adequate by 2 weeks of age and remains so at 40 weeks' postconception.
- Consideration should be given to reducing initial parenteral vitamin K doses in premature infants due to potential unforeseen consequences of high levels.
Objective:
Newborn infants are vitamin K deficient. Vitamin K status in full-term infants after intramuscular vitamin K supplementation at birth has been described. Similar information in growing premature infants has not been reported. The objective of this study was to assess vitamin K status in premature infants by measuring plasma vitamin K and plasma protein-induced in vitamin K absence (PIVKA II) from birth until 40 weeks' postconceptional age.
Methods:
Premature infants (/=1000 g) via total parenteral nutrition. After hyperalimentation, most received vitamin K-fortified enteral feedings with the remainder receiving unfortified breast milk. Blood was obtained for PIVKA II in cord blood and for PIVKA II and vitamin K at 2 weeks and 6 weeks after birth and at 40 weeks' postconception.
Results:
Of the 44 infants enrolled, 10 infants in each gestational age group completed the study. The patient characteristics for groups 1, 2, and 3 were as follows: gestational age, 26.3 +/- 1.7, 30.3 +/- 1.3, and 33.9 +/- 1.1 weeks; birth weight, 876 +/- 176, 1365 +/- 186, and 1906 +/- 163 g; and days of hyperalimentation, 28.9 +/- 16, 16.8 +/- 12, and 4.3 +/- 4 days, respectively. At 2 weeks of age, the vitamin K intake and plasma levels were highest in group 1 versus group 3 (intake: 71.2 +/- 39.6 vs 13.4 +/- 16.3 microg/kg/day; plasma levels: 130.7 +/- 125.6 vs 27.2 +/- 24.4 ng/mL). By 40 weeks' postconception, the vitamin K intake and plasma levels were similar in all 3 groups (group 1, 2, and 3: intake, 11.4 +/- 2.5, 15.4 +/- 6.0, and 10.0 +/- 7.0 microg/kg/day; plasma level, 5.4 +/- 3.8, 5.9 +/- 3.9, and 9.3 +/- 8.5 ng/mL). None of the postnatal plasma samples had any detectable PIVKA II.
Conclusions:
Premature infants at 2 weeks of age have high plasma vitamin K levels compared with those at 40 weeks' postconceptional age secondary to the parenteral administration of large amounts of vitamin K. By 40 weeks' postconception, these values are similar to those in term formula-fed infants. Confirming "adequate vitamin K status," PIVKA II was undetectable by 2 weeks of life in all of the premature infants. With the potential for unforeseen consequences of high vitamin K levels, consideration should be given to reducing the amount of parenteral vitamin K supplementation in the first few weeks of life in premature infants.vitamin K, PIVKA II, premature, total parenteral nutrition, enteral nutrition.
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