S.K., via email
Preeclampsia is a condition in which abnormally high blood pressure and other problems develop during pregnancy that can threaten the health-and even life-of both mother and child. Around 5 per cent of first-time pregnancies are affected and if you've had the condition once, you're more likely to get it again. Having a family history of preeclampsia also raises the risk of having the problem.
Signs and symptoms of preeclampsia (besides high blood pressure) include excess protein in the urine, swollen hands and face, headaches, abdominal pain and blurred vision.
There is no established way to prevent preeclampsia, and the only cure is to deliver the baby. That said, mounting evidence suggests that a number of nutritional supplements might be able to reduce the risk of this common complication of pregnancy.
Several studies suggest that supplementing with this amino acid may help prevent preeclampsia. A recent review of high-quality trials found that, among women at particular risk, those taking L-arginine were 66 per cent less likely to develop preeclampsia compared with those taking a placebo. The L-arginine takers were also half as likely to give birth prematurely.1
It makes sense that L-arginine supplements are helpful; the amino acid is essential for the production of nitric oxide, which is important for a healthy pregnancy.
In fact, low levels of nitric oxide and of L-arginine have each been linked to preeclampsia.2
Suggested daily dose: 3-4 g
A review by the prestigious Cochrane Collaboration, which pooled the results of 13 studies involving nearly 16,000 women in total, revealed that taking calcium supplements (at least 1 mg/day) reduced the risk of preeclampsia by more than half. The effects were greatest in women with calcium-poor diets and in those at high risk of preeclampsia.3
Suggested daily dose: 1-2 g (depending on the amount of dietary calcium)
It may be worth getting your zinc levels checked. A deficiency in this essential mineral has been found in some women with preeclampsia,4 though it's not yet clear whether zinc supplements can protect against the condition. One trial reported that zinc supplementation failed to prevent preeclampsia in healthy women.5
It could be that supplements are only beneficial in those deficient in the nutrient.
Magnesium is another mineral that might be linked to preeclampsia. One study found that magnesium levels in preeclamptic pregnant women were significantly lower than in pregnant women without the problem, suggesting that magnesium deficiency might be involved in its development.6
Again, it's unclear whether supplements would reduce the risk of preeclampsia, although one study found that magnesium sulphate can halve the risk of eclampsia-the final and most severe phase of preeclampsia-which can arise when preeclampsia is left untreated.7
Getting a daily dose of sunshine-a natural source of vitamin D-could help slash your risk of preeclampsia. In one US study, pregnant women with the lowest vitamin D levels were roughly four times more likely to have severe preeclampsia than pregnant women with higher D levels.8 Likewise, a Norwegian study discovered a 27 per cent reduction in preeclampsia risk among women taking vitamin D supplements during pregnancy compared with those taking no such supplements. No link was found between getting vitamin D from diet alone and having preeclampsia.9
Suggested daily dose: 10-15 mcg
Folic acid and vitamin B6
Supplementing with both these nutrients reduced homocysteine levels in one trial of women with a history of preeclampsia.10 High levels of homocysteine, a sulphur-containing amino acid, are believed to be involved in the development of the condition.
Suggested daily dose: 5 mg folic acid, 250 mg B6
Daily doses of this vitamin-like antioxidant reduced the incidence of preeclampsia by 44 per cent in women at high risk of developing the condition.11 Other research shows that preeclamptic women have lower blood levels of CoQ10 compared to normal pregnant women.12
Suggested daily dose: 200 mg
An holistic approach
Based on all this science, it's clear that a variety of vitamin, minerals and other nutrients are essential for a healthy pregnancy, and that perhaps not getting enough of them could lead to preeclampsia.
Rather than trying your luck with a few individual supplements, it may be best to see a qualified, experienced naturopathic practitioner, who can test you for any deficiencies and suggest a supplement programme tailored to your specific needs.
Ultimately, there's no one-pill-suits-all solution to preeclampsia; its prevention is about eating right and getting the full range of nutrients your body needs to function at optimum during pregnancy.
Other ways to reduce the risk
1 Avoid trans fats. These are found in foods like margarine, cakes, biscuits and fried foods. One study showed that diets high in trans fatty acids are associated with an increased risk of preeclampsia.1
2 Reduce stress. Psychological stress like anxiety and depression during pregnancy may lead to preeclampsia,2 so make time for relaxation techniques such as meditation or yoga.
3 Don't restrict salt or weight gain. Doing so can actually have detrimental effects.3
4 Minimize exposure to lead. Even low levels of this toxic metal are associated with raised blood pressure levels during pregnancy.4 See the US Environmental Protection Agency's website (www.epa.gov/iaq/lead.html) for ways to reduce exposure.
1 J Hum Hypertens, 2014; 28: 230-5
2 Hum Reprod Update, 1998; 4: 25-42; Placenta, 2006; 27: 438-44
3 Cochrane Database Syst Rev, 2014; 6: CD001059
4 Biol Trace Elem Res, 2010; 133: 162-70
5 Acta Obstet Gynecol Scand, 1996; 75: 725-9
6 Arch Gynecol Obstet, 2005; 273: 12-6
7 Lancet, 2002; 359: 1877-90
8 J Clin Endocrinol Metab, 2010; 95: 5105-9
9 Epidemiology, 2009; 20: 720-6
10 Am J Obstet Gynecol, 1998; 179: 135-9
11 Int J Gynaecol Obstet, 2009; 105: 43-5
12 Free Radic Biol Med, 2003; 35: 1453-6
WAYS TO REDUCE THE RISK REFERENCES
1 Gynecol Obstet Invest, 1998; 46: 84-7
2 Med Hypotheses, 2011; 77: 188-91
3 Baillieres Clin Obstet Gynaecol, 1995; 9: 497-507
4 Environ Health Perspect, 2011; 119: 664-9