Post-natal depression (depression after the birth of a child) is something that has broad recognition within the medical profession and even many parts of the community. In recent times, there has been growing awareness too that depression can commonly come on during the pregnancy itself. Depression that comes on during or up to 12 months after pregnancy is sometimes referred to as ‘peri-natal’ depression. The likelihood is that peri-natal depression has several potential causes which include social triggers (e.g. coping with the changes a newborn baby brings) and biological factors (e.g. hormonal changes including low levels of progesterone).
Nutritional factors may be a factor in depression, and for some years there has been considerable attention on the potential role of omega-3 fat as a natural antidepressant. Some scientists have, I suppose inevitably, become interested in whether omega-3 fats, especially those found in oily fish such as salmon and sardines, might have some role to play in peri-natal depression.
For instance, a study published earlier this month looked at the relationship between blood levels of omega-3 fats and depression in 16 depressed and 22 non-depressed women in the final third of their pregnancies [1]. High levels of DHA (one major type of omega-3 fat) and high levels of total omega-3 fats were both significantly associated with a reduced risk of depression. The authors raise the issue that during pregnancy omega-3 fats can be preferentially diverted to the foetus, putting expectant mothers at increased risk of omega-3 deficiency. This, I think, is a plausible mechanism for the underlying cause of peri-natal depression in at least some women.
The idea that peri-natal depression might be caused by a deficiency in omega-3 fats would be strengthened by research which finds the giving of omega-3 fats to pregnant women reduces risk of depression or depressive symptoms. Actually we do have such evidence, in the form of a study which found that 2 months of treatment with high dose omega-3 (3.4 g per day) in pregnant women with ‘major depressive disorder’ reduced depressive symptoms compared to placebo [2]. For more about this study, see here.
The evidence suggests that a good intake of omega-3 fats during and after pregnancy may have benefits for the mental health of women. There may be benefit for children too, in that omega-3 fats are thought to help in the development of the brain and visual function.
While oily fish (or omega-3 supplements) may be generally beneficial during and after pregnancy, there has been some concern in recent years regarding the fact that some fish species are contaminated with mercury. For more on this issue, see here.
References:
1. Rees AM, et al. Omega-3 deficiency associated with perinatal depression: Case control study. Psychiatry Res, 2009 March 4; [Epub ahead of print]
2. Su KP, et al. Omega-3 Fatty Acids for Major Depressive Disorder During Pregnancy: Results From a Randomized, Double-Blind, Placebo-Controlled Trial. J Clin Psychiatry, 2008 Mar 18 [Epub ahead of print].
