Department of Pediatrics, School of Medicine, University of Occupational and Environmental Health, Kitakyushu 807-8555, Japan.
Kitakyushu Yahata Higashi Hospital, Kitakyushu 805-0061, Japan.
Nutrients. 2020 Mar 16;12(3):780. doi: 10.3390/nu12030780.
Vitamin K is essential for the synthesis of few coagulation factors. Infants can easily develop vitamin K deficiency owing to poor placental transfer, low vitamin K content in breast milk, and poor intestinal absorption due to immature gut flora and malabsorption. Vitamin K deficiency bleeding (VKDB) in infancy is classified according to the time of presentation: early (within 24 h), classic (within 1 week after birth), and late (between 2 week and 6 months of age). VKDB in infancy, particularly late-onset VKDB, can be life-threatening. Therefore, all infants, including newborn infants, should receive vitamin K prophylaxis. Exclusive breastfeeding and cholestasis are closely associated with this deficiency and result in late-onset VKDB. Intramuscular prophylactic injections reduce the incidence of early-onset, classic, and late-onset VKDB. However, the prophylaxis strategy has recently been inclined toward oral administration because it is easier, safer, and cheaper to administer than intramuscular injection. Several epidemiological studies have shown that vitamin K oral administration is effective in the prevention of VKDB in infancy; however, the success of oral prophylaxis depends on the protocol regimen and parent compliance. Further national surveillance and studies are warranted to reveal the optimal prophylaxis regimen in term and preterm infants.
维生素 K 是合成少数凝血因子所必需的。由于胎盘转运不良、母乳中维生素 K 含量低以及肠道菌群不成熟和吸收不良导致的吸收不良，婴儿很容易发生维生素 K 缺乏症。婴儿维生素 K 缺乏出血症（VKDB）根据发病时间分类：早期（出生后 24 小时内）、经典（出生后 1 周内）和晚期（出生后 2 周至 6 个月）。婴儿期 VKDB，特别是晚发性 VKDB，可危及生命。因此，所有婴儿，包括新生儿，均应接受维生素 K 预防。纯母乳喂养和胆汁淤积症与这种缺乏症密切相关，导致晚发性 VKDB。肌内预防性注射可降低早发性、经典性和晚发性 VKDB 的发生率。然而，由于口服给药比肌内注射更容易、更安全、更便宜，因此最近预防策略倾向于口服给药。几项流行病学研究表明，口服维生素 K 可有效预防婴儿期 VKDB；然而，口服预防的成功取决于方案方案和家长的依从性。需要进一步的全国性监测和研究来揭示足月和早产儿的最佳预防方案。
