Maternal DHA levels tend to significantly decline during the third trimester of pregnancy. Maternal DHA supplementation seems to decrease the DHA decline during the third trimester. Some evidence suggests that infants that do not obtain DHA from breast milk or formula have delayed development of visual acuity compared to those that do receive an adequate amount of DHA. DHA is thought to be important for normal neural function and might play a key role in the structural development of neural and synaptic membranes.
During pregnancy, DHA is the most important nutrient for brain building. Omega-3 DHA makes up 97% of total omega 3 in the brain. It’s often said that women can become forgetful during pregnancy. This is thought to be due to the decrease in brain size that women with insufficent DHA will suffer from as the brain of the foetus develops.
There is some evidence that suggests the DHA can affect things like memory function, learning ability, and visual health. This is not surprising when one considers that long-chain polyunsaturated fatty acids (like DHA and other omega-3 fats), account for a third of the total fat in the brain’s grey matter.
DHA accrues rapidly in the human brain during the third trimester of pregnancy and during the early postnatal period. Accrual of DHA and other fatty acids at this time results in rapid brain tissue development and growth. Inadequate availability of polyunsaturated fatty acids such as DHA during fetal and infant development is thought to be a factor in development of behavioural, functional, and neurological disorders. Higher plasma DHA levels in women during birth might also be associated with greater central nervous system maturity in newborns, based on sleep-wake patterns.
Clinical research suggests that, when given to atopic women during pregnancy, DHA may protect against some respiratory symptoms in the infant. Maternal supplementation with DHA 400 mg daily from 18-22 weeks gestation until delivery reduces the incidence of phlegm with nasal discharge or nasal congestion by approximately 22% and the incidence of fever with phlegm and nasal discharge or nasal congestion by approximately 47% compared with placebo in the infants
There is some evidence to suggest that maternal supplementation with DHA 214mg daily may improve infant sleep patterning on the first day of life. Also, maternal supplementation with DHA 400mg daily from 16 weeks gestation until delivery may reduce the risk of poor language development in the infant at age 14 and 18 months and the risk of lower visual acuity at 2 months compared to placebo.
Overall, most evidence shows that maternal supplementation with DHA is not beneficial for infant cognitive development. However, due to the lack of significant safety concerns with DHA supplementation and the potential for some cognitive benefit, many experts recommend pregnant women take DHA 200mg daily.
Sources of DHA
Some seaweeds contain a small amount of DHA but would have to consume large amounts to get enough. Flax seeds and chia seeds contain alpha-lipoic acid which can convert to DHA, however this conversion is virtually insignificant. Generally, fish is the recommended source for omega-3, however, the only reason fish contain omega-3 is because they eat algae. Supplementing the algae form of DHA is not only better as it comes from the direct source, without potential contaminants from the sea such as dioxins or mercury, but it is also more sustainable for the fish.
This information is especially important for vegan mothers who would not eat the typically recommended 2 portions of fish per week.
Natural Medicine Database.