Prevention of rickets in preterm infants.
D006801:Humans; D006887:Hydroxycholecalciferols / Q000627:therapeutic use*; D007230:Infant, Low Birth Weight; D007231:Infant, Newborn; D007235:Infant, Premature, Diseases / Q000517:prevention & control*; D012279:Rickets / Q000517:prevention & control*
D006887:Hydroxycholecalciferols; C008088:alfacalcidol