Health Sciences Centre, Memorial University of Newfoundland, St. John's, NL, Canada.
Annu Rev Nutr. 2012 Aug 21;32:97-123. doi: 10.1146/annurev-nutr-071811-150742. Epub 2012 Apr 5.
Maternal adaptations during pregnancy and lactation appear to provide calcium to fetus and neonate without relying on vitamin D or calcitriol. Consequently, the blood calcium, calciotropic hormones, and skeleton appear normal at birth in the offspring of mothers who are severely vitamin D deficient or who lack calcitriol or its receptor. It remains unclear whether skeletal or extraskeletal problems will develop postnatally from exposure to vitamin D deficiency in utero. During the neonatal period, calcitriol-stimulated intestinal calcium absorption becomes the dominant mechanism of calcium delivery. The vitamin D-deficient neonate is at risk to develop hypocalcemia, rickets, and possibly extraskeletal disorders (e.g., type 1 diabetes). Breastfed babies are at higher risk of vitamin D deficiency because normally little vitamin D or 25-hydroxyvitamin D passes into breast milk. Dosing recommendations during pregnancy and lactation should ensure that the baby is born vitamin D sufficient and maintained that way during infancy and beyond.
妊娠和哺乳期的母体适应性似乎可以在不依赖维生素 D 或 1,25-二羟维生素 D3 的情况下向胎儿和新生儿提供钙。因此，在严重缺乏维生素 D 或缺乏 1,25-二羟维生素 D3 及其受体的母亲所生的后代中，出生时血液中的钙、钙调节激素和骨骼似乎正常。目前尚不清楚，在子宫内暴露于维生素 D 缺乏的情况下，骨骼或骨骼外问题是否会在出生后出现。在新生儿期，1,25-二羟维生素 D 刺激的肠道钙吸收成为钙输送的主要机制。维生素 D 缺乏的新生儿有发生低钙血症、佝偻病和可能的骨骼外疾病（例如，1 型糖尿病）的风险。母乳喂养的婴儿患维生素 D 缺乏症的风险更高，因为正常情况下，维生素 D 或 25-羟维生素 D 很少进入母乳。妊娠和哺乳期的剂量建议应确保婴儿出生时维生素 D 充足，并在婴儿期及以后保持这种状态。
