Women should take folic acid before becoming pregnant and during early pregnancy to prevent certain birth defects. These birth defects occur in the first months of pregnancy, after that there is no proven benefit of taking folic acid; yet most women continue to take folic acid as part of multivitamin throughout pregnancy.
However, concerns have been raised that continuing to take folic acid throughout pregnancy may increase the risk of developing gestational diabetes.
It’s a significant shift that underlines the continuing discovery of new evidence in relatively ‘young’ field of nutritional science.
Flinders University’s Professor Tim Green leads a research program that underlines the need to continue to take folic acid throughout pregnancy and to improve guidelines on folic acid supplementation use during pregnancy.
“Nutritional advice is constantly changing as new evidence becomes available, because it is a very complex science surrounding eating and nutrition,” explains Professor Green. “However, we do know that women who take folic acid supplements before pregnancy and during the first month of pregnancy can reduce certain serious birth defects including spina bifida that leads to various degrees of disability.
“Trials in the 1990s confirmed this, so medical authorities have been rigorously promoting women to take folic acid supplements as a consequence. However, we don’t know the risk of continuing to take folic acid through the later months of pregnancy, after the neural tube has closed at about four weeks after conception.
“Beyond this, we are seeing that gestational diabetes mellitus (GDM) in Australia has more than tripled, rising from 5.6% in 2010 to 19.3% in 2022. There are many reasons for this but continuing to take folic acid beyond the first trimester is one possibility.”
Professor Green’s research team is currently working on the FIG study (Folate In Gestation Study) which aims to optimise prenatal folic acid supplementation that can promote the best outcomes for both mothers and children.
This clinical study – funded by a BLOOM Grant through the Women and Children’s Hospital Foundation – aims to recruit 2,400 women for a large-scale trial in which women are randomised to supplements with and without folic acid after the first trimester, with the goal of informing decisions about folic acid use during later pregnancy.
They currently have about 800 participants, mostly recruited through social media, but Professor Green says it has been hard to convince women to give up their folic acid.
“Public health messaging over the last 20 years has been very effective in getting women to take folic acid to prevent birth defects. However, most people don’t realise what the benefit of taking folic acid is, so there is belief that folic acid should be taken throughout pregnancy. Some observational evidence says continuing to take additional supplements throughout a pregnancy may increase the risk of gestational diabetes.”
The FIG study aims to provide evidence to clarify this situation. This decentralised study can accept women from anywhere in Australia – and Professor Green hopes it can promote more thorough knowledge of folic acid and its effects during pregnancy.
“Public health is a very dynamic area where policy and practice need to consistently evolve as new evidence comes to light,” he says.
“Governments don’t act on observational studies. It requires the rigour of a large-scale clinical study of this type to present the type of evidence that can change policy – and our study into folate perfectly demonstrates this important transition from research into effecting policy and practice.”
Professor Green hopes to finish recruiting participants to the FIG study by the end of 2026, and believes the study will have capacity to broaden its scope of investigation to also cover other important pregnancy issues, such as recording number of pre-term deliveries, baby sizes, and even the cognitive development of children.
“Once we have women in the study, we can apply other outcomes, so there are many benefits that can come from something like the FIG study. Unfortunately, it takes a very long time between compiling evidence and taking action, but we are now underway and can expect very helpful outcomes.”