Taking high dose supplements of folic acid does not protect pregnant women from pre-eclampsia, a new study has found.
Experts have expressed disappointment in the findings and say the vital search for a strategy to prevent the potentially deadly condition must now go on.
“It’s disappointing that it hasn’t shown a reduction in pre-eclampsia and it just tells us that we need to keep looking”
Pre-eclampsia affects about 3-5% of pregnancies and is a leading cause of maternal and perinatal mortality and morbidity globally.
The international clinical study, published in the British Medical Journal, was launched to find definitive answers as to whether folic acid can provide women with protection after previous observational research had offered hope.
The trial involved 2,301 women who were between eight and 16 weeks’ pregnant at the start of the trial and had at least one risk factor for pre-eclampsia. The Folic Acid Clinical Trial featured women from Canada, the UK, Jamaica, Argentina and Australia.
The women all took up to 1.1mg of folic acid throughout pregnancy and around half were randomly chosen to receive an additional high daily dose (4mg) of the supplement. The other half were given a placebo.
The authors found that pre-eclampsia occurred in 169 out of 1,144 (14.8%) women in the folic acid group and 156 out of 1,157 (13.5%) in the placebo group.
As a result, they concluded that that high dose folic acid supplementation beyond the first trimester has no benefit for preventing pre-eclampsia.
“The search for an effective and acceptable strategy to prevent pre-eclampsia must continue”
They stated: “The lack of demonstrated benefit of high dose folic acid supplementation beyond the first trimester for women at high risk of developing pre-eclampsia indicates that high dose recommendation should now cease, and the search for an effective and acceptable strategy to prevent pre-eclampsia must continue.”
Guidelines currently still recommend that women take low dose supplements of folic acid before pregnancy and in the first trimester to help prevent certain birth defects in babies, such as spina bifida and anencephaly.
Lucy Chappell, National Institute for Health Research professor in obstetrics based at King’s College London, contributed to an editorial on the study.
Speaking to Nursing Times, she said: “It’s a really important study to have asked that question because there were very good reasons to think that folic acid might be a reasonable option to prevent pre-eclampsia.
“It’s obviously disappointing that it hasn’t shown a reduction in pre-eclampsia and it just tells us that we need to keep looking for other preventative treatments,” she said.
Professor Chappell said many studies previously conducted into possible preventative treatments of pre-eclampsia had started out positive but landed at a dead end.
She said the “jury is still out” on whether calcium could help lower the risk and that a “big trial” was set to be carried out in the UK in 2019. Aspirin has also been proven to offer some protection, Professor Chappell noted.
She said: “We will carry on working to find [preventative treatments], because it’s just so important for us and for the women both in the UK and globally that we can see a reduction in maternal and baby deaths from this disease.”
She said it was “essential” that the results of the study did not “dilute the message” about the benefits of taking folic acid to prevent neural tube defects in babies.