Higher folic acid intake linked to early pregnancy bleeding in new study
25 Aug 2026
Experts say the findings need to be interpreted carefully and should not change the established advice on folic acid use.
Researchers examined information from more than 2,400 first-time mothers. They compared women who were recruited before and after Australia introduced mandatory folic acid fortification of bread-making flour in 2009.
Women in the later group were more likely to use higher-dose folic acid supplements and generally had higher folate levels.
The study found that women taking 800 micrograms or more of folic acid a day were more likely to report spotting or mild vaginal bleeding during the first 16 weeks of pregnancy.
The association was stronger among pregnancies involving a male baby, where the reported risk of vaginal bleeding was more than twice as high compared with women who did not take folic acid supplements.
Researchers stressed that the findings do not change the well-established role of folic acid in reducing the risk of serious birth defects. Instead, they said the results suggest that supplement doses may need further investigation, particularly in countries where foods are fortified with folic acid.
RACGP NSW&ACT Chair Dr Rebekah Hoffman said pregnant women should continue to be advised to take folic acid and iodine supplements.
She explained that standard folic acid supplementation is generally around 400–500 micrograms, while a much higher dose of 5 milligrams may be recommended for women at increased risk of neural tube defects.
The researchers said the findings may be important for reviewing how much folic acid women receive from both supplements and fortified foods.
Study senior author Professor Claire Roberts said around 400 micrograms a day may be enough for many women in countries where folic acid is added to foods, but more research is needed to understand the findings.
Dr Hoffman also said the study highlights the need for GPs to ask pregnant patients about all supplements they are taking, including vitamins, as these may not always be considered medicines by patients.
Researchers also identified a possible relationship between folic acid intake, fetal sex and pregnancy outcomes. However, they said more research is needed to understand why the association with bleeding appeared different between pregnancies involving boys and girls.
Dr Hoffman said the findings may show a correlation rather than a direct cause of bleeding.
Experts emphasised that the study should not discourage pregnant women from taking folic acid. Instead, supplementation should be discussed with a GP or other healthcare professional.
Higher folic acid intake linked to early pregnancy bleeding in new study
Source: Flinders University study and RACGP newsGP