DHA, also called docosahexaenoic acid, commonly known as brain gold, is a kind of unsaturated fatty acid, DHA is an important component for the maintenance and growth of the cells of the nervous system, is an important component of the retina and brain, and has an important role in the vision and intellectual development of the fetus and infant. The benefits of DHA supplementation for pregnant women are beneficial to both themselves and their fetuses, and the benefits are as follows: 1) promote fetal brain development: optimize the composition of phospholipids in fetal brain cone cells; 2) promote the maturation of retinal photoreceptor cells: mainly due to DHA to increase the maturity of nerve cells; 3) enhance brain cell development: DHA is the main component of nerve conduction cells and cell membrane formation; 4) reduce postpartum depression. 4, reduce postpartum depression: research shows that adequate amounts of DHA can reduce the occurrence of postpartum depression; 5, reduce the risk of preterm birth: DHA supplementation during pregnancy increases the average 2.6 days of pregnancy, reducing the risk of preterm birth before 34 weeks by about 25%. Second, the best time to supplement DHA DHA after pregnancy, should be supplemented in accordance with the three stages of fetal brain development, as follows: 1, the first stage: 3-6 months of pregnancy is the peak stage of brain cell proliferation; 2, the second stage: the seventh month of pregnancy to the birth of the child, is the second important stage of brain cell growth and development; 3, the third stage: 6-12 months after the birth of the baby, is the last peak of brain cell growth. Third, the source of DHA supplementation pregnant women can get DHA through a variety of ways, common sources of supplementation are as follows: 1, sea fish and seafood; 2, dried fruits: such as peanuts, melon seeds, cashew nuts, pistachios, etc.; 3, vegetable oils: including mustard seed oil, flax oil, etc.; 4, DHA products. Fourth, the side effects of DHA overdose DHA overdose can easily lead to a decline in immunity of pregnant women, causing indigestion, such as abdominal distension, belching, etc.. Secondly, it can lead to nutritional imbalance in the body and affect the growth and development of the fetus. In addition, it can also lead to the occurrence of related diseases, such as blood clotting dysfunction. Therefore, when taking DHA should not be excessive, it is best to take it under the guidance of a doctor’s regulation, do not oversupply yourself.