Pregnant women occasionally experience an increase in blood pressure known as gestational hypertension or pregnancy-induced hypertension (PIH). In a more severe condition called pre-eclampsia, a rise in blood pressure is accompanied by protein in the urine and sometimes by sudden weight gain, swelling in the face or hands, and other symptoms. When left untreated, pre-eclampsia can lead to seizures (called eclampsia) or liver, kidney, or bleeding problems in the mother and distress or growth retardation in the fetus. Unless pre-eclampsia is mild, doctors usually seek to deliver the baby early.


Principal Proposed Natural Treatments

Although there are no fully established natural treatments for the prevention of pre-eclampsia or PIH, calcium has shown significant promise.


A meta-analysis (statistical review) of 11 studies of calcium supplementation in pregnancy, involving a total of more than 6,000 women, found that calcium slightly reduced the risk of pre-eclampsia and hypertension, particularly in two groups of women: those at high risk for hypertension and/or those with low calcium intakes. 1]]>

However, by far the largest single study in the meta-analysis found no benefits. ]]>2]]> In this ]]>double-blind]]> study, researchers gave either 2 g of calcium or placebo daily to 4,589 women from weeks 13 to 21 of their pregnancy onward. In the end, researchers found no ]]>significant]]> decreases in rates of hypertension or pre-eclampsia—not even when they looked specifically at women whose daily calcium consumption mirrored that of women in developing countries.

The meta-analysis included this negative study in its calculations, but still found that calcium seemed to be helpful.

In a subsequent double-blind, placebo-controlled study published in 2006 and conducted by the World Health Organization, calcium supplements (1.5 g per day) were tried in 8,325 pregnant women whose calcium intake was inadequate. ]]>28]]> Calcium failed to reduce the incidence of pre-eclampsia. However, it did appear to reduce the severity of pre-eclampsia episodes.

The bottom line: Calcium might be of some benefit for those pregnant women who are at high risk for hypertension or deficient in calcium. However, for well-nourished, low-risk women, effects are likely to be minimal or nil.

All of the above refers to preventing pre-eclampsia. One double-blind, ]]>placebo-controlled]]> study suggests that calcium supplements are not effective for treating pre-eclampsia that has already developed. ]]>3]]>

Note: Calcium appears to offer the additional benefit of reducing blood levels of lead during pregnancy. ]]>4]]>

Interestingly, weak evidence hints that use of calcium by pregnant mothers might reduce risk of hypertension in their children. ]]>33]]>

For more information, including dosage and safety issues, see the full ]]>Calcium]]> article.


Other Proposed Natural Treatments

Antioxidants]]> are substances that fight free radicals, dangerous naturally occurring molecules that may play a role in pre-eclampsia. For various theoretical reasons, it has been proposed that use of antioxidants by pregnant women may help stop pre-eclampsia from developing. One double-blind, placebo-controlled study found evidence that a combination of the antioxidant ]]>vitamin E]]> (400 IU daily) and ]]>vitamin C]]> (1,000 mg daily) reduced incidence of pre-eclampsia. ]]>5]]> Benefits were also seen in another study of this combination, ]]>25]]> as well as a study using a mixture of numerous antioxidants along with other nutrients. ]]>32]]> Additionally, a double-blind trial found potential preventive effects with the antioxidant substance ]]>lycopene]]> (taken at 2 mg twice daily). ]]>21]]> However, researchers caution that further study is necessary: Many other treatments have shown initial promise for preventing pre-eclampsia, but lost luster when subsequent studies were performed.

The most prominent of these once-promising substances include ]]>folate]]> , ]]>magnesium]]> , ]]>omega-3 fatty acids]]> (fish oil), and ]]>zinc]]> . ]]>7-17,22,24]]> Furthermore, a large follow-up study of vitamin E combined with vitamin C failed to find any benefit, ]]>29]]> and in a review of 10 studies involving a total of 6,533 subjects, antioxidant supplementation (of mostly vitamins E and C) during pregnancy did not reduce the risk of pre-eclampsia or any of its complications. ]]>34]]> In addition, a high-quality randomized trial of 1,365 high-risk pregnant women found that daily supplementation with combination vitamin E (400 IU) and vitamin C (1,000 mg) through delivery was not associated with reduced risk of pre-eclampsia or other serious outcomes. ]]>35]]>

Other studies have looked at possible treatments of pre-eclampsia once it has already occurred. Results are somewhat positive, though mixed on the potential benefits of ]]>arginine]]> for this purpose. ]]>26,27,30]]>]]>Evening primrose oil]]> has failed to prove helpful, ]]>20]]> as has a combination of ]]>vitamin C]]> , ]]>vitamin E]]> , and the drug allopurinol. ]]>6]]> However, ]]>magnesium]]> , taken by injection but not orally, appears to provide meaningful benefits. ]]>18,19,23]]>

One study failed to find n-acetyl cysteine helpful for severe pre-eclampsia. ]]>31]]>