DHA through pregnancy for maternal depression and neurodevelopment.
Epidemiological studies from the Uunited States and Europe demonstrate that higher intakes of n-3 long chain polyunsaturated fatty acids (LCPUFA) from fish and seafood during pregnancy are associated with a reduced risk of depressive symptoms in the postnatal period, as well as improved developmental outcomes in the offspring. Of the n-3 LCPUFA, docosahexaenoic acid (DHA) is most commonly associated with these health outcomes.
This double blind multicentre randomised controlled trial aimed to assess whether DHA supplementation during the last half of pregnancy reduced the risk of postpartum maternal depression and improved early cognitive development in offspring. It came under the banner of DHA to Optimize Mother Infant Outcome (DOMInO) trial, conducted in 5 Australian perinatal centres.
The study included 2399 women with singleton pregnancies at less than 21 weeks gestation. Participants were randomised into treatment and control groups. Participants in the treatment group were given three 500 mg capsules of DHA rich fish oil concentrate, providing 800 mg/d of DHA and 100 mg/d of eicosapentaenoic acid (EPA). Participants in the control group were given three 500 mg vegetable oil capsules without DHA. These capsules contained a blend of three non genetically modified oils (rapeseed, sunflower and palm) in equal proportions designed to match the poly-, monounsaturated and saturated fatty acid profile of the average Australian diet. Participants were phoned two weeks after enrolment, then at 28 and 36 weeks gestation to document adverse events and to encourage adherence.
The concentration of DHA in cord blood was measured using capillary gas chromatography, to provide an independent biomarker of adherence. DHA concentration in the plasma phospholipids of cord blood from women in the treatment group was, as expected, greater than control (median 7.22% vs. 6.09% total phospholipid fatty acids P < 0.001).
Although dietary intake of n-3 fatty acids was not assessed in this trial, women in Australia are known to have low dietary intakes of n-3 LCPUFA; this was evidenced by the fact the median plasma phospholipid DHA concentration in cord blood of the DOMInO control group was virtually identical to the concentration observed in a cohort of Dutch pregnant women with biochemical DHA insufficiency.
Participants completed a self administered Edinburgh Postnatal Depression Scale (EPDS) at 6 weeks and 6 months postpartum. The researchers considered this to be the best form of assessing probable depressive disorder. Women with a high score were referred to their general practitioners for more formal medical assessment.
The percentage of women reporting high levels of depressive symptoms during the first 6 months postpartum did not differ significantly between the DHA and control groups (9.67% vs. 11.19%; adjusted RR, 0.85; 95% CI, 0.70-1.02; P = 0.09). The researchers have suggested the possibility that the lower than expected rate of women with high levels of depressive symptoms in the control group is explained by the Hawthorn effect; whereby participating in a trial, with increased contact with researchers, helped to prevent depressive symptoms.
Primary neurodevelopment (at 18 months) was assessed by 1 of 4 study psychologists using the Cognitive and Language Composite Scales of the Bayley Scales of Infant and Toddler Development, Third Edition (BSID-III). All 96 preterm children and 630 randomly selected term children from Adelaide, Australia, were chosen for BSIDIII assessment (n = 726). The families and trial staff did not know which children had been randomly selected for follow up until the infants were 12 months old.
Mean cognitive scores of children from women allocated to the DHA group did not differ significantly from mean scores of children of women from the control group. However fewer children from the DHA group had scores indicating delayed cognitive development when compared with controls.
Secondary analysis showed that fewer children in the DHA treated group had delayed cognitive development compared with the control group. Although girls exposed to higher dose DHA in utero had lower language scores and were more likely to have delayed language development than girls from the control group. There was a smaller incidence of preterm birth (associated with poor neurocognitive outcomes) in the DHA treated group.
The frequency of hemorrhage and antenatal hospitalisations did not differ between groups. Similarly there were no differences between the groups in maternal report of nose bleeds, vaginal blood loss, constipation, nausea or vomiting at 28 and 36 weeks gestation.
The study concluded that while n-3 fatty acid consumption is an important component of maintaining health through gestation and birth, the benefit of higher intake may be less effective than currently thought and should be investigated further.
Kathleen Murphy MNHAA
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|Title Annotation:||Reviews of medical journal articles|
|Publication:||Australian Journal of Medical Herbalism|
|Date:||Dec 22, 2010|
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