Researchers compared the effectiveness of omega-3 polyunsaturated fatty acid supplementation on depression during pregnancy or postpartum depression (PPD) after childbirth. This review suggested that omega-3 deficiency is a causative factor in postpartum depression, affects neurotransmission and induces neuro-inflammation in brain. Beneficial effects of omega-3 supplementation on prenatal and postpartum depression were also noted. The brain neurotransmission function were restored via lengthy replenishment of docosahexaenoic acid in neuronal cellular membrane. Supplementation of eicosapentaenoic acid (EPA) suppresses the omega-6 fatty acids induced neuro-inflammation and depression. During pregnancy or postpartum, dietary supplementation with omega-3 fatty acids rich in EPA annihilates symptoms of depression.