Spring may be around the corner, but colds and flu don’t read calendars. In the U.S., influenza activity can rumble on into May, and common colds circulate in every season because they’re driven by viruses, not weather. That’s why simple hygiene—washing hands, minimizing close contact with people who are ill—matters year-round. For those who are pregnant or newly postpartum, it also makes sense to think about the nutrients that help shore up immune defenses for you and your baby. Among them, the marine omega-3s DHA and EPA keep showing up in the research.
A Baby’s Immune System: A Rapid, Orchestrated Debut
Newborn immunity flips on quickly after birth. Using next-generation cell profiling, researchers followed premature and full-term infants and found that the earliest weeks feature a predictable sequence of immune shifts—almost like a choreographed routine. Mapping that “dance” is the first step; the same teams plan to follow children into later childhood to see how early immune patterns connect to conditions like allergies, asthma, and autoimmune disease.
Where Omega-3s Meet Immunity
Omega-3s aren’t just anti-inflammatory; they appear to fine-tune immune function. Laboratory work has shown that EPA and DHA can enhance B-cell activity. These white blood cells help coordinate the antibody response and develop long-term “memory” to past infections—an effect that could matter when you’re aiming to build resilient defenses rather than simply turn inflammation down.
During Pregnancy: Signals for the Baby’s Lungs and Early Infections
One of the most informative trials on this topic comes from the Copenhagen Prospective Studies on Asthma in Childhood. Starting at 24 weeks’ gestation, 736 women were randomized to receive 2.4 grams per day of combined EPA and DHA or an olive-oil placebo through one week postpartum. Over the first three years of life, children in the omega-3 group had a lower risk of persistent wheeze or asthma than those in the placebo group, a relative reduction of about one-third. The benefit was most pronounced when mothers began with the lowest omega-3 blood levels, suggesting that baseline status matters. The researchers also saw fewer lower respiratory tract infections, while outcomes such as eczema and allergic sensitization did not differ significantly.
Findings from Mexico add another piece. In that study, women took 400 mg of DHA daily from mid-pregnancy until birth. When parents reported on their infants’ health at one, three, and six months, the babies in the DHA group tended to get over common illness symptoms faster. At one month, combined cold symptoms were less frequent; across the first half-year, bouts of fever, cough, wheeze, nasal discharge, and other complaints were shorter in duration. The pattern points to a modest but meaningful advantage in early recovery rather than a guarantee against getting sick.
What This Means for Expectant and New Mothers
Taken together, these studies suggest that getting enough DHA—and, in some cases, a higher combined EPA+DHA dose—during late pregnancy can support respiratory health in infancy and may trim the time babies spend under the weather. These are population-level trends, not certainties for every child, and they sit alongside well-established prenatal DHA benefits for preterm birth risk and for brain and eye development.
Day-to-day, the practical steps are straightforward. Keep up the basics of infection control, aim for a nutrient-dense diet, and make conscious room for marine omega-3s. For many, that means eating low-mercury oily fish regularly or choosing an algae- or fish-oil supplement that provides DHA (and, when appropriate, EPA). If fish isn’t on your menu, or if you simply want to know whether your habits are delivering enough for you and your baby, talk with your clinician about your intake and consider objective testing to establish a baseline and track changes over time. As the season changes, the principle doesn’t: consistent, measured support for your immune system is a year-round investment.
