Why are omega-3 fats important to take in the third trimester?

Omega-3 fats are particularly important from the third trimester through the first 18 months of life for development of the brain, retina, and central nervous system. During this time period, the developing fetus accumulates 50 to 70 milligrams of DHA per day,^[1] and this process continues to occur through 18 months of age.^[2] This is why most studies initiate supplementation during the third trimester. It is generally recommended that fish oil fats are supplemented from the onset of pregnancy,^[3] so there’s no need to omit supplementation outside of the third trimester.