Pregnant women should start taking DHA supplements in the fifth month of pregnancy. After the fifth month of pregnancy, the fetus is developing faster in hearing, vision and touch, which is a critical period. If you take enough DHA during this period, it can promote the development of the fetus’ visual nerve and the division of the central neurons in the brain, which is the fastest maturation period and the period with the greatest demand for DHA. If enough DHA is supplemented during this period, it can promote fetal visual and neurological development, which has different effects on the improvement of fetal intelligence, and the baby’s vision and intelligence will be greatly improved after birth. DHA should be supplemented from the fifth month of pregnancy, until the fetus is born six months, because before six months the baby can not eat supplementary food, so there are certain restrictions on the role of taking drugs, after six months can let the baby eat on their own.