Postnatal depression: a bad case of the blues
New evidence now suggests that a simple supplement could be the key to preventing postnatal depression (PND), a devastating condition that affects 10 to 15 per cent of women after having a baby.
Selenium—a trace mineral found naturally in foods such as Brazil nuts and fish—has previously been shown to reduce the risk of cancer, infertility and a range of other conditions. Now, researchers have found that taking 100 mcg/day of selenium during pregnancy can effectively ward off PND.
In a randomized, double-blind, placebo-controlled trial (considered the ‘gold standard’ for scientific evaluation), 166 women, pregnant for the first time and in their first trimester of pregnancy, took either selenium or a dummy pill every day until delivery. After delivery, the women were monitored for symptoms of PND over a period of eight weeks, using the Edinburgh Postnatal Depression Scale.
The researchers found that the women who had supplemented with selenium had significantly higher levels of the nutrient in their blood by the time they gave birth. More important, their ratings of depress-ion were significantly lower com-pared with the controls.
“These findings suggest that supplementation with selenium during pregnancy might be an effective approach for the prevention of postpartum depression,” the researchers concluded (J Matern Fetal Neonatal Med, 2010 Jun 8; Epub ahead of print).
Although more research is needed to confirm these results, this study was not the first to suggest a link between nutrition and PND. Indeed, almost 20 years ago, a UK study proposed that low levels of zinc might play a role in the mood disorder (J Nutr Environ Med, 1992; 3: 35–42). In addition, other evidence suggests that inadequate intakes of vitamin B12 and folate, iron and calcium—commonly seen in preg-nant women who consume a typical Western diet—could also be contrib-uting to PND (J Am Diet Assoc, 2009; 109: 1566–75).
Most of the research, however, has focused on omega-3 fatty acids. Numerous studies have found a correlation between low levels of these essential fats—found in oily fish and flaxseed—and a higher incidence of maternal depression (J Am Diet Assoc, 2009; 109: 1566–75).
In one study, Belgian researchers compared 10 women with PND and 38 women without the condition. They found that those with the disorder were more likely to have low concentrations of omega-3s, as well as a higher ratio of omega-6 (found in vegetable oils, mayonnaise, almonds, chicken and turkey) to omega-3 fats (Life Sci, 2003; 73: 3181–7).
Another study looked at fish consumption during pregnancy and found that women with the lowest intakes were more likely to be taking antidepressants for PND (Am J Clin Nutr, 2009; 90: 149–55).
These studies suggest that supplementing with omega-3 might be a simple way to prevent and treat PND. In fact, a preliminary trial showed that PND symptoms were cut nearly in half with eight-week supplementation of eicosapenta-enoic acid (EPA) and docosapenta-enoic acid (DHA) (Acta Psychiatr Scand, 2006; 113: 31–5). Taking a daily multivitamin/mineral supplement may also be beneficial.
Treatments that work
Good nutrition is not the only way to counteract PND. Studies show a variety of ways to deal with the disorder without resorting to dangerous antidepressants.
• Breastfeeding. According to a recent review, breastfeeding is one of the best ways to prevent and treat PND, providing it does not cause pain or other problems. When breastfeeding goes well, it protects mothers against stress (Int Breastfeed J, 2007; 2: 6). One US study found that breastfeeding women had lower perceived stress, depression and anger, and reported more positive life events, than did formula-feeders (Biol Res Nurs, 2005; 7: 106–17). In another study, women with PND were significantly less likely to be breastfeeding, and more likely to report that they were suffering from greater life stress and anxiety (Psychoneuroendocrinology, 2007; 32: 133–9).
• Exercise. Regular exercise is known to have stress-reducing and antidepressant effects (Prev Med, 2000; 30: 17–25). Indeed, aerobic exercise proved to be just as effective as the antidepressant sertraline for major depressive disorder—and with lower rates of relapse (Psychosom Med, 2000; 62: 633–8). In new mothers, a pro-gramme of exercise and health-care education was found to improve postnatal wellbeing and cut the risk of developing PND by 50 per cent (Phys Ther, 2010; 90: 348–55).
As it may be difficult for new mothers to find the time to exercise, joining a pram-walking group may be more feasible than joining a gym. One trial found that just such a pram-walking programme was more effective than attending a social-support group for reducing symptoms of PND. A bonus was that, as the women’s fitness levels improved, so did their symptoms (Int J Nurs Pract, 2004; 10: 177–94).
u Massage. Studies show that attending a baby-massage class can improve PND as well as mother–infant interactions (J Affect Disord, 2008; 109: 189–92).
Giving massage to mothers may also have benefits. Mothers who received aromatherapy mass-age showed significant improve-ments in both physical and mental status compared with those who did not (J Midwifery Womens Health, 2006; 51: e21–7). Also, pregnant women given two massage therapy sessions a week for 12 weeks by their partner were less depressed than controls after giving birth, and also showed lower levels of cortisol, the stress hormone. Their newborns were also less likely to be born prematurely and to have low birth weights (Infant Behav Dev, 2009; 32: 454–60).
• Bright-light therapy. Introduced to treat SAD (seasonal affective disorder), phototherapy may also help in PND. Controlled trials are lacking, but the case studies of two women with postpartum depression showed significant reductions (by 75 per cent) in depression scores, using the Hamilton Rating Scale for Depression, after just four weeks of daily, 10,000-lux, bright-light therapy (Am J Psychiatry, 2000, 157: 303–4).
• Transcranial magnetic stimula-tion (TMS). This non-invasive brain-stimulation technique was recently tested on nine anti-depressant-free women with PND. After receiving 20 repetitive TMS sessions for four weeks, the new mothers were then assessed after 30 days, three months and six months.
The results showed a signifi-cant reduction in depression symptoms by the end of the second week of treatment. After four weeks, eight out of nine patients had complete remission of symptoms and, at the six-month follow-up, seven of these patients were still depression-free (Brain Stimul, 2010; 3: 36–41).
• Acupuncture. This can work just as well as the proven conventional treatments for major depression (Complement Ther Med, 2001; 9: 216–8), and one trial even found acu-puncture to be promising for the treatment of depression during the pregnancy (J Affect Disord, 2004; 83: 89–95).
• St John’s wort. This herb (Hypericum perforatum) is a well-known treatment for depression. However, some experts note that long-term studies are needed to determine its safety during breastfeeding (Pharmacopsychiatry, 2002; 35: 29–30). Nevertheless, in one Canadian study with a follow-up period of two years, the herb had no adverse effects on either milk production or infant growth (J Clin Psychiatry, 2003; 64: 966–8).
• Cognitive therapy. Several studies have found that ‘talking’ therapies can help women with PND. Indeed, women who received therapy focused on interpersonal relationships and role changes were more likely to recover from their depressive episodes than women not so treated (44 per cent vs 14 per cent, respectively) (BMJ, 2003; 327: 1003–4).
• Peer and midwife support. In fact, just talking to someone who has experienced PND and suc-ceeded in overcoming it can be effective in preventing it. A Canadian study found that women who spoke to volunteer mothers over the phone were less likely to be depressed after giving birth compared with those who received the standard care (BMJ, 2009; 338: a3064).
Midwives can also play a role in reducing the risk of developing PND. A British study compared conventional postnatal care—regular visits by the midwife for the first two weeks, followed by health-visitor checks and a GP appointment within six to eight weeks—with midwife-led person-alized care for three months. The women receiving the midwife-led care showed significantly better psychological wellbeing, with an overall 40-per-cent reduction in the risk of depression (Lancet, 2002; 359: 370–1, 378–85).
PND: an inflammatory response
Recent research has pinpointed inflammation as a key factor in depression. One review, carried out by University of New Hampshire researcher Kathleen Kendall-Tackett, noted that increased inflammation in the blood is not simply a risk factor for depression, but is the risk factor that underlies all others. In other words, inflammation is the mechanism by which previously identified risk factors—such as psychological trauma, sleep problems, low income and lack of social support—increase the risk of depression.
Postnatal women are particularly vulnerable because their inflammation levels are naturally and inevitably elevated in the last trimester of pregnancy, and this increase persists after giving birth. Moreover, the common experiences of new motherhood, such as sleep disturbance, postnatal pain and past or current psychological trauma, act as stressors to cause inflammation levels to rise even further.
According to Kendall-Tackett, treatments that reduce inflammation and lower maternal stress—such as breastfeeding, omega-3 supplements and exercise—are particularly effective against PND. If left untreated, however, it can persist for a year or more.
One new avenue of research would be to determine whether or not anti-inflammatory approaches—used proactively—can stop depression from arising in the first place (Int Breastfeed J, 2007; 2: 6).
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