AA and DHA are also required for the endothelial lining of the blood vessels. These fatty acids are highly susceptible to peroxidation. Sixty percent of the structural material of the brain is lipid.
Fetal growth takes place at a low oxygen tension which favours lipid anabolism for brain growth.
The placenta extracts AA and DHA from the maternal circulation to pass to the fetus. A preterm baby is denied the placental enrichment of AA and DHA and are physiologically unprepared to breathe atmospheric oxygen. Blood levels of AA and DHA at birth in preterm babies are below what is expected at term. SOD activity is still less than two-thirds of a term baby at expected date of delivery. The preterm baby is, in consequence, born with deficits of AA and DHA and anti-oxidant protection.