Infants will be randomized to receive the combined enteral DHA/ARA supplement within the first 48 hours after birth to 36 weeks postmenstrual age. The randomization procedure will follow a stratified permuted block scheme to fulfill two goals: (1) randomize infants into one of four arms and (2) ensure an adequate sample size within each week of gestational age. Preterm infants will be randomized using random permuted blocks within each of the 5 birth gestational age strata. When treatment assignment is open and sample size is not overtly large, a block randomization procedure with randomly chosen block sizes can maintain treatment assignment balance and reduce the potential for selection bias. This approach will also ensure that preterm infants of all eligible gestational ages at birth are approximately equally represented in each of 4 arms of the trial, thus ensuring that important comorbidities and standard of care applicable to infants of different gestational ages at birth are also approximately equally distributed across the study arms. There is no placebo for this study. There is no blinding in this study. Consent will also be obtained from the mother of the infant, as they will be asked to provide milk samples if they're breastfeeding their infant, and maternal medical history and demographical data will be recorded.
