Docosahexaenoic Acid (DHA) is a long-chain omega-3 polyunsaturated fatty acid that plays an important structural role in the body. It is categorized as an essential fatty acid because the human body cannot produce enough of it to meet demands, especially during periods of high need like pregnancy. DHA is transferred across the placenta to the developing baby, making maternal intake a required component of a pregnant individual’s diet or supplement regimen.
The Role of DHA in Fetal Brain and Eye Development
DHA is a major building block for the fetal central nervous system and visual organs. It is highly concentrated in the cerebral cortex, the part of the brain associated with memory, attention, and language, as well as the light-sensing cells of the retina in the eye. The brain is composed of about 60% fat, and DHA is the most prevalent omega-3 fatty acid found within its structure.
This fatty acid helps maintain the necessary fluidity and flexibility of neural cell membranes, which is a structural property that supports communication between brain cells. Membrane fluidity is a factor in the proper signaling and function of synapses, the junctions that allow neurons to pass electrical or chemical signals to one another. Adequate DHA status during gestation is associated with improved fine motor skills and visual acuity in children.
The accumulation of DHA in the fetal brain occurs continuously throughout gestation but becomes most rapid and intense during the third trimester. During this final stage of pregnancy, the fetus requires an estimated 67 milligrams of omega-3 fatty acids daily to support this accelerated growth. Since the fetus cannot synthesize enough DHA on its own, consistent maternal intake is necessary to prevent depletion of the mother’s supply.
Recommended Daily Intake and Dietary Sources
Health authorities generally recommend that pregnant individuals consume a minimum of 200 to 300 milligrams of DHA daily. This baseline recommendation is intended to ensure adequate levels for both maternal health and the accelerated demands of the developing fetus. Some guidelines suggest a total intake of at least 350 to 450 milligrams of combined DHA and EPA (another omega-3 fatty acid) per day.
Dietary sources of DHA primarily include fatty, cold-water fish like salmon, sardines, herring, and anchovies. Consuming two servings of low-mercury fish per week can help meet a portion of the daily requirement. However, the typical diet of many pregnant individuals often falls significantly short of these recommendations.
For those who do not eat fish regularly or are concerned about contaminants, supplementation ensures adequate intake. Plant-based sources, such as flaxseed or walnuts, contain the shorter-chain omega-3 precursor alpha-linolenic acid (ALA). However, the human body is very inefficient at converting ALA into DHA (often less than one percent), making direct sources necessary. Algae-based supplements offer a plant-derived source of pre-formed DHA, suitable for vegetarians or vegans.
Supplement Timing and Quality Considerations
Starting DHA supplementation is recommended before conception or as soon as pregnancy is confirmed to build maternal stores. Since the highest demand occurs late in pregnancy, continuing supplementation throughout all three trimesters and into the breastfeeding period is important. Consistent intake ensures a steady supply of this fatty acid for the baby’s ongoing development.
When selecting a DHA supplement, focusing on quality and purity is important to address concerns about environmental contaminants. Fish oil supplements can be processed through molecular distillation, a technique that effectively removes toxins such as mercury and polychlorinated biphenyls (PCBs). Third-party testing and certification from independent organizations are reliable indicators of high quality.
These third-party certifications, such as the International Fish Oil Standards (IFOS) Program, verify that the supplement meets strict limits for heavy metals, contaminants, and potency. Algal oil supplements, sourced from the microalgae that fish consume, are naturally free of these contaminants and provide a clean source of DHA. Choosing a purified and certified product ensures the benefits of DHA are received without associated risks.