 Long-chain polyunsaturated fatty acids (LC-PUFA), particularly docosahexaenoic acid (DHA) and arachidonic acid, are, respectively, n-3 and n-6 family members and play an important role in fetal and infant growth and development. Pregnancy and lactation impose special nutritional needs for the mother-fetus situation. Since the LC-PUFA required by the fetus is supplied by preferential placental transfer of preformed LC-PUFA rather than their precursor, it has been hypothesized that additional maternal supply of LC-PUFA, especially DHA, during pregnancy may improve maternal and infant outcomes.