Very preterm neonates <= 32+6 weeks GA receiving PN will be randomized to receive their PN prepared with standard trace elements containing 5 mcg/kg/day of manganese, or to PN prepared with no added manganese. Randomization assignment will be double masked. All participants will have whole blood manganese measurements at baseline, at 2 weeks of postnatal age, and at 8 weeks postnatal age. Because manganese is present as a contaminant in many of the ingredients used to prepare neonatal PN, this study hypothesizes that neonates randomized to no added manganese in their PN will maintain whole blood manganese concentrations above the lower limit of normal.

