Daisuke Nishi1, Kuan-Pin Su2, and Yutaka Matsuoka1
1National Center of Neurology and Psychiatry, Japan
Depression is one of the leading causes of disability worldwide. The prevalence of depression during pregnancy is around 10% (1, 2), and its consequences can include difficulty performing usual activities, failing to seek prenatal care, not maintaining an adequate diet, and using tobacco, alcohol, and other harmful substances. It can also carry the risk of self-harm or suicide. In addition, fetal growth as well as infant temperament and later behavior in childhood can be affected.
Antidepressants including selective serotonin reuptake inhibitors (SSRIs), cognitive behavioral therapy (CBT), and interpersonal psychotherapy (IPT) are all options for treating depression. Although there are no data from randomized controlled trials (RCTs) assessing the safety of SSRIs in pregnancy, some observational studies have noted an increased risk with SSRIs for congenital cardiac malformations or pulmonary hypertension in newborns(3, 4). In addition, fetuses whose mothers have chronic depression and thus are continuously exposed to SSRIs while in the womb are more likely to be born preterm than infants with partial or no exposure.(5). In a population screening study conducted among pregnant women attending antenatal clinics, only about 1 of 10 pregnant women with depression reported adequate antidepressant medication use (6). Professional guidelines recommend both CBT and IPT for pregnant women with mild or moderate depression (7). However, pregnant women cannot always access CBT and IPT, so it is important to identify alternative safe strategies for managing pregnant women’s depression.
Omega-3 polyunsaturated fatty acids (PUFAs) such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) are fatty acids essential to health that can be obtained only through the diet, from fish especially. During pregnancy, omega-3 fatty acids are used to help form fetal tissues. A study in rats has shown that the amount of omega-3 PUFAs in the brain can be reduced after a single reproductive cycle when there is an insufficient supply of omega-3 PUFAs from the diet, and this can adversely affect neuronal function (8). Another study has shown that the brain decreases in size during pregnancy in humans (9). Taking these results together, a lack of omega-3 PUFAs might cause antenatal and postpartum depression.
Omega-3 PUFAs might also be beneficial in managing depression. A growing number of RCTs have been carried out to verify their efficacy against depression, and the latest evidence does suggest the efficacy of omega-3 PUFAs that contain 60% or more EPA out of the total EPA + DHA content (10, 11). To date, however, most RCTs have failed to prove the efficacy of omega-3 PUFAs specifically for pregnant women with depression, but this is likely because the supplements used in these RCTs did not contain 60% or more EPA. Only one study from Taiwan using supplements with a high ratio of EPA to DHA has shown the efficacy of omega-3 PUFAs for depression in pregnancy (12). There are also reports of some individual cases of pregnant women with depression and psychiatric illness (13) or schizophrenia (14, 15) being helped by omega-3 PUFA supplementation. A small open-label, flexible-dose trial in 15 pregnant depressed women also supports the effectiveness of omega-3 PUFAs (16).
Since omega-3 PUFAs are essential for proper development of the central nervous system, they might be a promising alternative for the prevention and treatment of depression in pregnant women. Because fish consumption varies across countries, which might affect the efficacy of omega-3 PUFAs, we plan to conduct an RCT to examine the efficacy of omega-3 PUFA supplements containing 60% or more EPA for depressive symptoms in pregnant women in Taiwan and Japan, to provide findings in Asian populations. We hope that this study will provide evidence that helps to promote the mental health of mothers and children.
References
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