Background: Docosahexaenoic acid (DHA) and arachidonic acid (ARA) are relevant polyunsaturated fatty acids (PUFA) derived from alpha-linolenic acid (ALA) and linoleic acid (LA), respectively. These are important in pregnancy and lactation periods because of their benefits to the developing fetus and infant. Currently, the high prevalence of gestational obesity has led to a revision of PUFAs recommendations in these periods, due to changes in the lipid profile of women marked by a higher consumption of n-6 PUFA. Objective: This review aims to present an updated compilation of evidence on DHA and ARA during gestation and lactation. Methods: The literature review was performed in different databases, PubMed, Scopus, Web of Science, Scielo, ISI, and Ovid MedLine, highlighting the importance of DHA and ARA for newborn development. Results: An adequate intake of n-3 PUFA, especially DHA, in the mother during pregnancy and the postnatal period is important for the normal development of the child's brain. Maternal DHA supplementation increases DHA levels in mothers, but its direct link to infant neurodevelopment remains unclear. Obesity generates changes in the FA profile of pregnant women, causing an imbalance of n-3 and n-6 PUFA. An adequate level of DHA benefits children's cognitive function. However, a potential connection exists to the infants' inflammatory profile. Conclusion: During gestation and lactation periods, an adequate DHA intake and n-6/ n-3 PUFA ratio (especially for obese women) are important for the optimal growth and brain development of the child.