In the UK, over 90% of women of childbearing age have blood folate levels below recommended thresholds, placing them at risk of folate-sensitive neural tube defects (NTDs). NTDs, including spina bifida, affect approximately 1,000 pregnancies annually, one of the highest rates in Europe, and frequently result in miscarriage or termination. Despite long-standing NHS guidance recommending a 400µg daily folic acid supplement before and during early pregnancy, uptake is low: 75% of women planning pregnancy do not take supplements, and 45% of pregnancies are unplanned. Since 2008, folate status among UK women has declined by over 30%, highlighting the limited effectiveness of supplementation strategies alone.
Mandatory folic acid fortification of white flour is now being implemented in the UK, following international evidence that fortification improves folate status and reduces NTD prevalence. However, uncertainties remain regarding its effectiveness across diverse population groups, particularly ethnic minorities and women from deprived backgrounds, who are at heightened risk of folate deficiency and less likely to benefit from this public health intervention. Furthermore, the wider maternal and infant health impacts of fortification, and its cost-effectiveness, have not been systematically evaluated.
This project will evaluate the impact of the UK folic acid fortification strategy on maternal-infant health outcomes using longitudinal clinical data from national birth cohorts. Interrupted time series (ITS) analysis will be used to assess trends in maternal anaemia, miscarriage, NTDs, and child neurodevelopment before and after fortification. Outcomes will be stratified by ethnicity, socioeconomic status, and geography to identify inequalities. Parallel analyses will investigate changes in maternal folate status in early pregnancy and associations with clinical outcomes. The study will also assess health economic implications and provide real-time evidence to government organisations.
This research will generate policy-relevant evidence on the effectiveness, equity, and value of the UK’s folic acid fortification strategy.

