Docosahexaenoic acid (DHA) and arachidonic acid (AA) have a critical effect on the health and neuronal development of the fetus and newborn. Their deficiency has been associated with increased neonatal morbidity, especially in preterm newborns at birth. Direct DHA supplementation during the first few weeks of life could prevent this deficiency.

The aim is to increase DHA levels in the red blood cell membrane while maintaining the fetal proportion to AA in preterm infants through enteral administration of DHA/AA in a safe, tolerated, and effective manner. This approach aims to avoid the decline in DHA/AA levels and the consequences of their deficiency.

The study is a single-center, prospective, randomized, controlled, open-label study involving preterm infants admitted to the Neonatology Department of Vall d'Hebron University Hospital in Barcelona.

Polyunsaturated fatty acids (PUFAs), especially DHA and AA, are essential fatty acids that have a high relevance in the growth and development of the fetus and newborn. Preterm infants are at high risk of suffering from a deficiency of these essential fatty acids. This deficit would cause serious visual impairments and alterations in neuronal development, as well as an increase in morbidity in these patients.

The external contribution after birth is mainly based on that provided through the mother's own milk (premature milk) and when it is not sufficient, it is supplemented with bank milk. This enteral milk intake is not complete until after the first week of life. In addition, the proportion of bank milk administered in this phase is higher than the mother's own milk. This bank milk has a lower concentration of DHA mainly.

If complete enteral feeding is not achieved until 10 days of age and this is mainly done at the expense of bank milk with a lower DHA content than the mother's premature milk, it seems reasonable to directly supplement the preterm infant with DHA and AA from the first days of life as indicated with other fortifications and thus avoid the risk of deficiency and its consequences. This intake should be similar to that of assimilated intrauterine: 50-60 mg/kg/day. Despite these statements, specific and direct supplementation of DHA and AA is not carried out as standard clinical practice in preterm infants. They have only been carried out in the context of studies.

Enteral supplementation of DHA and AA during the first month of life in the preterm newborn will ensure optimal levels of DHA and AA similar to those achieved in intrauterine life, which will be essential for the correct growth of the newborn and its optimal neuronal development.

This supplementation is not a common healthcare practice in the Neonatology Departments. Our study proposes a safe and effective way to avoid DHA and AA deficiency in the first days of life and its consequences.

Inclusion Criteria:

• Newborns with a gestational age between 23 and 32 weeks admitted to the Neonatology Service of the Vall d'Hebron University Hospital and with informed consent signed by the parents or legal guardians.

Exclusion Criteria:

• Severe malformation incompatible with life.
• Impossibility of enteral nutrition during the expected duration of the study (30 days).