Salle B L, Delvin E E, Lapillonne A, Bishop N J, Glorieux F H
Department of Neonatology and Human's Nutrition Center, Hôpital Edouard Herriot, Lyon, France.
Am J Clin Nutr. 2000 May;71(5 Suppl):1317S-24S. doi: 10.1093/ajcn/71.5.1317s.
During pregnancy, maternal serum concentrations of 25-hydroxyvitamin D, the circulating form of vitamin D, correlate with dietary vitamin D intake. Maternal serum concentrations of 1,25-dihydroxyvitamin D, the hormonal circulating and active form of vitamin D, are elevated during pregnancy; 1,25-dihydroxyvitamin D is synthesized mainly by the decidual cells of the placenta and allows for increased calcium absorption. The fetus is entirely dependent on the mother for its supply of 25-hydroxyvitamin D, which is believed to cross the placenta. Hypocalcemia and increased parathyroid hormone secretion induce synthesis of 1,25-dihydroxyvitamin D after birth in both full-term and preterm neonates. Nevertheless, serum concentrations of 25-hydroxyvitamin D are a rate-limiting factor in the synthesis of 1,25-dihydroxyvitamin D. In vitamin D-replete infants, circulating 1,25-dihydroxyvitamin D concentrations are higher than those observed in older infants. In countries where dairy products are not routinely supplemented with vitamin D, maternal vitamin D supplementation during pregnancy is necessary. However, there is no indication for the use of pharmacologic doses of vitamin D or its metabolites in the perinatal period.
孕期，母体血清中维生素D的循环形式25-羟基维生素D的浓度与膳食维生素D摄入量相关。维生素D的激素循环及活性形式1,25-二羟基维生素D在孕期母体血清中的浓度会升高；1,25-二羟基维生素D主要由胎盘的蜕膜细胞合成，可促进钙吸收增加。胎儿完全依赖母体供应25-羟基维生素D，据信其可穿过胎盘。低钙血症和甲状旁腺激素分泌增加会在足月和早产新生儿出生后诱导1,25-二羟基维生素D的合成。然而，25-羟基维生素D的血清浓度是1,25-二羟基维生素D合成的限速因素。在维生素D充足的婴儿中，循环中的1,25-二羟基维生素D浓度高于较大婴儿。在乳制品通常不常规添加维生素D的国家，孕期母体补充维生素D是必要的。然而，在围产期没有使用药理剂量的维生素D或其代谢物的指征。
