Global Comparison of Erythrocyte EPA and DHA Concentrations in Pregnant Women

BACKGROUND: Adequate concentrations of long-chain omega-3 (LC n-3) PUFAs, specifically EPA and DHA, are critical for maternal health and fetal development during pregnancy. Despite their importance, global data on maternal blood concentrations of EPA+DHA remain sparse and inconsistent, partially due to differences in measurement methodologies. OBJECTIVES: This study assessed global maternal blood concentrations of EPA+DHA during pregnancy by synthesizing data from observational studies and RCTs from the last 20 y (2004-2025). METHODS: Non-red blood cell (RBC) based EPA+DHA blood concentrations from published studies were standardized using conversion equations to estimate relative EPA+DHA percentages in RBCs estimated Omega-3 Index (eO3I). Country mean eO3I levels were classified into 4 categories based on literature-defined thresholds. RESULTS: An analysis of 66 studies involving 33,390 pregnant women from 28 countries revealed significant geographical disparities in eO3I levels. Only the Seychelles, Norway, and Ghana achieved desirable levels (>8%). Some Asian countries (Japan, Taiwan, and Singapore), Malawi, Tanzania, and Northern European nations (Belgium, Netherlands, Iceland, Denmark, and Sweden) exhibited sufficient/moderate levels (>6%-8%). Most countries, including the United States, Canada, Mexico, Brazil, Chile, Australia, the United Kingdom, Germany, Switzerland, Italy, Croatia, and Spain, demonstrated insufficient/low levels (>4%-6%). Meanwhile, China, India, and Iran showed very low/undesirable levels (≤4%). CONCLUSIONS: These findings highlight widespread insufficiency in maternal EPA+DHA status globally, with particularly severe deficiencies observed in Asia and parts of Europe. This study underscores the need for more research to ultimately define the optimal EPA+DHA concentrations during pregnancy using standardized blood biomarkers, along with pregnancy-specific reference ranges, to facilitate targeted nutritional strategies aimed at optimizing health outcomes for both mother and child. Future studies should focus on addressing data gaps, refining intake recommendations, and promoting accessible supplementation strategies.