DHA Supplements May Reduce Stress in Pregnant Women

Laura Putre

November 07, 2014

Pregnant women living in high-stress situations may benefit from supplements of the omega-3 fatty acid DHA (docosahexaenoic acid), according to a randomized controlled trial published online November 5 and in the December issue of Obstetrics & Gynecology. The reduction in cortisol output may improve the uterine environment for the developing fetus.

Black women who took DHA supplements reported feeling less stressed at 30 weeks of pregnancy and had lower levels of the stress hormone cortisol than women who did not receive the supplement, according to Kate Keenan, PhD, professor, Department of Psychiatry, University of Chicago, Illinois, and colleagues.

Sixty-four black women who were between 16 and 21 weeks pregnant and who were either receiving or eligible to receive Medicaid enrolled in the study. All participants lived in urban, low-income environments and were between 20 and 30 years old. Researchers randomly assigned the women to receive either 450 mg of DHA per day or a placebo. Research assistants checked on participants three times a week by telephone to determine whether they were taking their supplements on schedule.

The investigators measured participants' stress levels through self-report on questionnaires and through saliva sample tests both at the start of the study and at 24 and 30 weeks of pregnancy. The saliva tests measured the women's cortisol levels before and after they took the Trier Social Stress Test, which measures stress levels in response to various mental exercises, such as solving math problems and giving a speech. The researchers controlled for depression and negative life events.

At 30 weeks of pregnancy, perceived stress was significantly lower among participants supplementing with DHA compared with among women receiving the placebo (P = .029). In addition, cortisol output in response to a stressful situation was 20% lower in the women who received the supplement than in the placebo group (P = .004).

DHA levels of low-income pregnant women are typically much lower, at a quarter to one third of recommended levels, the researchers note.

The investigators note several limitations of the study, including the relatively small sample size and the inclusion of only black women in the study, which may limit the generalizability of the findings. However, they restricted enrollment to African Americans because of previously identified differences between ethnic groups in cortisol responses to stress.

Given the decrease in cortisol outputs, the authors speculate that DHA supplementation might have a positive effect on infants' developmental outcomes. Previous research has shown that newborns of women with high levels of cortisol during the final weeks of pregnancy were more "high reactive," exhibiting more crying and motor activity. In addition, high levels of psychological and environmental stress during pregnancy are linked to developmental problems in children, including increased anxiety, difficulty paying attention, and impaired learning.

"Data from our preliminary study are compelling in terms of the potential effect on health disparities in maternal and neonatal health, a significant public health problem that is poorly understood," the authors write. "The findings, however, are in need of replication."

Supported by the National Institutes of Health and the University of Chicago Institute for Translational Medicine. Nordic Naturals provided the nutritional supplement and placebo. The authors have disclosed no relevant financial relationships.

Obstet Gynecol. Published online November 5, 2014. Abstract


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