Why Preterm Birth Deserves Your Attention
Pregnancy is joyous, but it’s also full of very real worries—finances, nutrition, and the health of both mother and baby. Among the biggest concerns is preterm birth, defined by the CDC as delivery before 37 weeks. In the U.S., more than one in ten infants were born preterm in 2016, and the rate has crept upward after years of decline. Early preterm birth—before 34 weeks—carries even higher risks because every extra day in the womb supports critical growth. Stark disparities persist as well; for example, rates are substantially higher among Black mothers than white mothers. Anything safe and practical that helps extend gestation matters.
Where Omega-3s Fit In
Alongside fundamentals such as keeping a healthy weight, managing blood pressure and blood sugar, and avoiding smoking and alcohol, nutrition plays a meaningful role. The marine omega-3s—EPA (eicosapentaenoic acid) and especially DHA (docosahexaenoic acid)—are of particular interest because they are structural fats in the brain, eyes, and placenta and influence inflammatory and hormonal signaling that can affect timing of birth.
What the Research Is Showing
A large collaboration between Harvard T.H. Chan School of Public Health and Denmark’s Statens Serum Institut examined mothers’ omega-3 status during early and mid-pregnancy. Women with lower blood levels of EPA+DHA had a significantly higher risk of early preterm delivery than those with higher levels. Converting those plasma values to red-blood-cell (RBC) terms—a longer-term indicator—suggests that women whose RBC DHA sits below roughly the mid-3% range face markedly greater odds of delivering before 34 weeks compared with women closer to ~5%. While population differences and genetics mean findings should be replicated, the signal is consistent: identifying and correcting low DHA early in pregnancy could be protective.
Trials That Move From Association to Action
Randomized trials strengthen the case. In one controlled study, pregnant women who took 600 mg of DHA daily from mid-pregnancy to delivery had higher maternal and cord DHA, slightly longer gestation, higher birth weight and head circumference, fewer births before 34 weeks, and shorter neonatal hospital stays. Systematic reviews pooling many trials report fewer early preterm and overall preterm births with omega-3 intake. Ongoing large studies are testing higher daily DHA intakes—around 800–1000 mg—from early pregnancy to confirm optimal dosing.
Testing Matters: Know Your DHA, Then Personalize
Diet records are helpful, but blood tells the truth. Measuring omega-3 status via a simple finger-prick and assessing RBC DHA (or the Omega-3 Index, which is EPA+DHA in RBCs) gives a clear starting point. Early-pregnancy DHA above roughly 4% on an RBC basis is a reasonable protective target, and many programs set a prenatal goal closer to 5%. If results are low, increasing DHA intake through diet and/or supplementation and then retesting provides objective feedback that you’ve moved into a safer range.
Smart Ways to Raise DHA Safely
Food first is a sound approach. Choose low-mercury, DHA-rich fish such as salmon, sardines, herring, and trout, and aim for regular servings across the week. Avoid high-mercury species like shark, swordfish, king mackerel, and limit albacore (white) tuna. If your appetite for fish is limited or nausea makes intake inconsistent, a quality prenatal supplement that clearly lists DHA content can help you reach and maintain protective levels. Many trials used 600 mg DHA daily, and some women with low blood levels may benefit from higher amounts under clinical guidance. Because needs vary, testing before and during pregnancy is the best way to fine-tune your plan.
A Practical, Personalized Plan
Begin by discussing omega-3s with your prenatal provider and arrange an early test of omega-3 status. If your DHA is low, increase dietary fish that are naturally rich in DHA and add a daily DHA supplement; if your level is already in the protective range, maintain that intake. Retest during the second trimester to ensure you’re on track. This measure-adjust-monitor rhythm turns a general recommendation into a plan tailored to your pregnancy.
The Bottom Line
Preterm birth risk has many drivers, but omega-3 status—especially DHA—is one you can measure and modify. Testing early, targeting a protective DHA level, and using a mix of seafood and supplements to maintain it is a simple, evidence-aligned strategy to support a longer, healthier pregnancy for you and your baby.
