Frontiers in Nutrition, January 2026 | William Yakah et al., Columbia University
Women who took omega-3 supplements alongside prenatal vitamins had meaningfully lower rates of preterm birth and small-for-gestational-age birth than women on prenatal vitamins alone, according to a study of 9,461 pregnancies published in Frontiers in Nutrition. Researchers led by William Yakah of Columbia University analyzed data from the nuMoM2b cohort across eight US medical centers.
The preterm-birth rate among women on prenatal multivitamins plus omega-3s was 5.0%, compared with 8.4% among those on prenatals alone. Small-for-gestational-age rates were only 2.8% versus a much higher 4.5% for those supplementing with vitamins alone. The preterm-birth association held up after researchers adjusted for income, age, and health status.
DHA, the omega-3 fatty acid most critical during pregnancy, is a primary structural building block of the developing fetal brain and lungs. The fetus draws its entire supply from the mother. Many prenatal vitamins contain little or no DHA, and dietary sources are often inadequate or deliberately avoided during pregnancy due to mercury concerns in fatty fish.
Only 13% of women in the study were taking both vitamin and omega-3 supplements. Unfortunately, the gap this study points to is the rule, not the exception.
Tip: Quality prenatal supplementation involves two components. The multivitamin should be comprehensive, covering both vitamins and essential minerals at clinically validated levels, with attention to mineral bioavailability, which varies significantly across brands. The omega-3 addition, as this study suggests, should center on DHA. A prenatal omega-3 supplement should provide a substantial dose of DHA alongside EPA, sourced from coldwater fish oil that has been molecularly distilled to remove mercury and other contaminants naturally present in marine sources. As always, discuss changes to prenatal supplementation with your obstetrician.
