Maternal nutrition is a key determinant of fetal development, particularly in the context of neural regulation and maturation. Omega-3 polyunsaturated fatty acids, especially docosahexaenoic acid (DHA), play an essential role in neural differentiation, synaptogenesis, myelination, and neuroprotection. While the neurodevelopmental benefits of DHA are well-documented, the effects of excessive maternal DHA intake and the potential long-term consequences on offspring neurophysiology remain poorly understood. The purpose of this review is to synthesize current findings on the role of DHA in fetal neural development, emphasizing biochemical mechanisms and developmental outcomes. It further explores emerging concerns associated with excessive intake, the varied responses to intake, the varied sources of supplements, and the influence of maternal metabolic conditions, such as diabetes, on DHA bioavailability and fetal brain development. Finally, the review highlights the need for individualized supplementation strategies in maternal nutrition and considers the potential epigenetic implications of prenatal DHA exposure, to ultimately inform future research and therapeutic strategies in maternal–fetal health and neurodevelopmental biology.