If you suffer with allergy and asthma during your pregnancy, then you might be interested in hearing that recent research has shown that babies born to women with low levels of vitamin E in their blood are more likely to suffer wheezing and asthma. This might make you think that it would be a good idea to take a vitamin E supplement during pregnancy - just in case.
"Premature babies tend to be deficient in antioxidants and suffer from oxygen stress, so we thought that they might benefit if their mothers received vitamins during pregnancy," says Professor Anne Greenough of King's College, London. "We also thought that giving mothers antioxidants might help improve lung growth and function in their babies."
Funded by Asthma UK, Prof. Greenough and colleagues at Imperial College, followed up the multi-centre Vitamins in Pregnancy study which included a number of women under the care of St Thomas' Hospital, London. The aim of this study was to prevent pre-eclampsia (high blood pressure in pregnancy) and the 643 women took either high doses of vitamin C and vitamin E or a placebo during their pregnancy. The mothers completed a questionnaire for the researchers when their child reached the age of two. This data showed that taking the vitamins made no difference to the risk of the child wheezing. In fact, a sub-group of 118 women had their medical records analysed and this showed that the children born to women who had received the vitamins actually required more GP care and more emergency hospital treatment.
"These babies were more likely to be delivered prematurely and the costs of their care were higher - but this wasn't due to respiratory problems," Prof. Greenhough said.
So why the contradiction between these results and the earlier trials suggesting that antioxidants should benefit a baby's lungs? The initial trials were not randomised, which means there could be some bias in the results. The Vitamins in Pregnancy trial was randomised - the women and the researchers did not know who was getting vitamins and who was getting a placebo. This makes its results more reliable and robust.
"We do not know what causes asthma in babies - it is probably very complex. Our evidence is important as it suggests that antioxidants are not helpful," says Prof. Greenhough. She adds that women should still take any vitamins that are recommended, such as folic acid, and not to worry about the impact that these high dose vitamins had on the babies in the sub-group. As ever, the best advice on preventing asthma in the unborn child is to avoid general air pollution during pregnancy.
To find out more visit our Asthma Air Purifier Information Page.
Greenough A et al Respiratory outcomes in early childhood following antenatal vitamin C and E supplementation Thorax Online First October 1 2010