Can vitamins prevent pre-eclampsia?

by Sue Gilbert

I recently heard that during the second half of pregnancy women should take vitamins E and C to prevent pre-eclampsia. What should I be taking?

answer

It is too early for a recommendation. The study you are referring to was reported in the 4th September 1999 edition of the Lancet (1999; 354; 788﷓789, 810-816). It is the first study of its kind. Although the findings are promising, no scientific study is ever considered conclusive until similar studies are conducted that replicate the results. The only recommendation that can be made from this study is that more such studies should be carried out.

Results of the recent study, carried out in London, showed that daily supplements of vitamin E and C significantly reduced a pregnant woman's risk of developing pre-eclampsia. The participants of the study were women considered at high risk for this condition. (Women with pre-existing hypertensive disorders or family histories of hypertension are considered at increased risk of pre﷓eclampsia.) Therefore, the study cannot be applied to women not at risk and studies should be carried out with women who do not fall into the high-risk group.

Pre-eclampsia is a condition that generally begins some time after the 20th week of pregnancy. It is characterised by dangerously high blood pressure, protein in the urine and swelling of the face, hands and feet. It can result in detachment of the placenta from the uterine wall, premature birth, smaller babies, an increased risk of needing a Caesarean section and, in the worst case, death of the baby and/or the mother. Because of the seriousness of the condition, studies to find means of preventing and treating pre-eclampsia are very important.

In previous studies, it was found that calcium supplements helped to prevent the condition. However, it is important to note that the level of recommended supplements only ensured that pregnant mums reached the recommended intake or just slightly above.

The most recent US government survey shows that women of child-bearing age are consuming less than 600 milligrams of calcium per day. Vitamin supplements taken during pregnancy cannot supply 100% of the required vitamins and minerals because the pill would become too large to swallow. Therefore supplementing your calcium intake is recommended, either by eating calcium﷓rich foods or taking a calcium supplement. However, total intake should not exceed the 1200 milligrams currently recommended for pregnant women.

If your vitamin supplements do not supply all of your daily needs for vitamins C and E, then taking additional supplements that bring you up to recommended levels is safe and advisable. In the study mentioned earlier, women were given 1000 milligrams of vitamin C and 400 IU of vitamin E, both well above the recommended daily amounts. Vitamin C and vitamin E are both well tolerated at levels above recommended intakes and show few signs of toxicity when taken in high doses by non-pregnant people.

Many people, even scientists who know the evidence is not conclusive, take supplements of both in the hope of taking advantage of the anti-oxidative effects of these two vitamins and their potential for preventing diseases and premature ageing. For pregnant women, taking a supplement beyond the proven safe and adequate intake is putting their unborn babies at possible risk of as yet unknown side effects.

Getting more vitamin C and E from food sources is a safe way to increase your intake of those two vitamins. It is almost impossible to eat enough foods to reach potentially unsafe levels. Foods rich in vitamin C include citrus fruits, green and red peppers, cantaloupe melon, potatoes, tomatoes, strawberries, cabbage and broccoli. Foods rich in vitamin E include vegetable oils — especially corn, soy and wheat germ oil — sunflower seeds, wheat germ, sweetcorn, cashews, almonds, corn oil margarine and peanuts.

If you are at risk of pre-eclampsia, speak to your doctor about this study. Review your diet to be sure you are getting enough calcium, vitamins E and C. For those not at risk, ensuring that you are getting 100% of your recommended intake makes sense, along with enhancing your diet with foods rich in those nutrients.