Researchers studied whether eating a Mediterranean diet during pregnancy could improve a baby’s heart health. They followed over 1,200 pregnant women at high risk for complications and divided them into three groups: one that ate a Mediterranean diet, one that did stress-reduction exercises, and one that received normal pregnancy care. Babies whose mothers ate the Mediterranean diet (rich in olive oil, nuts, and healthy foods) had healthier heart function markers at birth compared to the regular care group. The stress-reduction group didn’t show the same benefits. These findings suggest that what pregnant women eat may directly affect their baby’s heart development, though more research is needed to understand exactly how.

The Quick Take

  • What they studied: Does eating a Mediterranean diet during pregnancy improve a baby’s heart function?
  • Who participated: 1,221 pregnant women (ages 19-23 weeks along) who were at higher risk of having smaller babies. The study took place in Barcelona, Spain between 2017-2020.
  • Key finding: Babies whose mothers ate a Mediterranean diet had better heart function markers at birth. Only 6.4% of these babies showed signs of heart stress, compared to 12% in the regular care group. The Mediterranean diet babies also had stronger right heart chambers and thinner heart muscle walls.
  • What it means for you: If you’re pregnant or planning to become pregnant, eating a Mediterranean-style diet (lots of olive oil, nuts, vegetables, fish, and whole grains) may support your baby’s heart health. However, this is one study, so talk to your doctor before making major diet changes.

The Research Details

This was a secondary analysis of a larger study called IMPACT BCN. Researchers took data from a randomized controlled trial, which is considered the gold standard in medical research. The study randomly divided pregnant women into three equal groups to compare different approaches fairly. One group received education about Mediterranean eating, free olive oil and walnuts, and monthly counseling sessions. Another group completed an 8-week mindfulness and stress-reduction program designed for pregnant women. The third group received standard pregnancy care as a comparison. All participants were followed until delivery, when researchers measured special heart health markers in the baby’s cord blood and performed heart ultrasounds at 33-34 weeks of pregnancy.

This research design is important because it helps prove cause-and-effect relationships rather than just showing that two things happen together. By randomly assigning women to different groups, researchers could compare the Mediterranean diet’s effects while controlling for other factors that might affect baby’s heart health. The study measured both blood markers (NT-proBNP) and actual heart structure/function through ultrasound, giving a complete picture of heart health.

This study has several strengths: it involved over 1,200 participants, used random assignment to reduce bias, measured outcomes in multiple ways, and was conducted at a reputable university hospital. However, not all participants completed all measurements (990 had ultrasounds, 746 had cord blood tests), which is typical but worth noting. The study was published in a respected medical journal, suggesting it passed expert review.

What the Results Show

The most important finding was that babies whose mothers followed the Mediterranean diet had significantly lower rates of heart stress markers at birth. Only 6.4% of babies in the Mediterranean diet group had high levels of NT-proBNP (a protein that indicates heart strain) compared to 12% in the regular care group. This difference was statistically significant, meaning it’s unlikely to have happened by chance. Additionally, these babies showed better heart function on ultrasound: their right heart chambers pumped more efficiently (30.4% versus 28.1% in the regular care group), and their heart muscle walls were thinner and healthier (2.95mm versus 3.16mm). Thinner, more efficient heart walls in fetuses suggest the heart isn’t working as hard to pump blood, which is a good sign of health.

Interestingly, the stress-reduction group (mindfulness-based program) did not show the same improvements in fetal heart function as the Mediterranean diet group. This suggests that diet may be more directly important for fetal heart development than stress reduction alone, though stress reduction may have other pregnancy benefits not measured in this study.

Previous research has shown that poor nutrition and high stress during pregnancy can harm fetal heart development. This study builds on that knowledge by showing that a specific healthy diet pattern—the Mediterranean diet—may actively protect and improve fetal heart function. The Mediterranean diet is already well-known for heart health benefits in adults, so these findings extend that benefit to developing babies.

Several limitations should be considered: not all enrolled women completed all heart measurements, so the final analysis included fewer participants than started the study. The study only looked at pregnancies at high risk for complications, so results may not apply to all pregnancies. The study was conducted in Spain and may reflect local food availability and healthcare practices. Finally, researchers measured heart function at one point in time (birth), so they couldn’t track long-term outcomes in childhood or adulthood.

The Bottom Line

Pregnant women, especially those at higher risk for complications, may benefit from adopting a Mediterranean diet pattern. This includes eating plenty of olive oil, nuts, vegetables, whole grains, fish, and legumes while limiting processed foods and red meat. This recommendation is supported by moderate evidence from this well-designed study, though more research is needed. Discuss dietary changes with your healthcare provider to ensure they fit your individual needs and any dietary restrictions you may have.

This research is most relevant to pregnant women, especially those identified as higher risk for pregnancy complications. It’s also important for partners, family members, and healthcare providers who support pregnant women. Women planning to become pregnant may also benefit from adopting these eating habits. This research is less directly applicable to non-pregnant individuals, though the Mediterranean diet has many general health benefits.

Heart changes begin during pregnancy and continue developing throughout gestation. The benefits measured in this study were evident by the time babies were born (around 33-34 weeks when ultrasounds were done). If you adopt a Mediterranean diet during pregnancy, you may expect to see potential benefits in your baby’s heart health by the third trimester, though individual results may vary.

Want to Apply This Research?

  • Track daily Mediterranean diet adherence by logging servings of olive oil, nuts, vegetables, whole grains, and fish. Set a goal of 5+ servings of vegetables/fruits daily and 2-3 servings of fish weekly. Use the app to monitor consistency week-to-week.
  • Start by adding one Mediterranean element to each meal: drizzle olive oil on salads, add a handful of nuts as a snack, include fish twice weekly, and swap refined grains for whole grains. Use app reminders for meal planning and grocery shopping aligned with Mediterranean principles.
  • Create a weekly Mediterranean diet scorecard tracking: olive oil use, nut consumption, vegetable servings, fish meals, and whole grain choices. Review monthly trends to identify patterns and adjust. If pregnant, share progress with your healthcare provider at prenatal visits.

This research suggests a potential benefit of Mediterranean diet during pregnancy but does not prove it prevents all heart problems. Individual results vary, and this study focused on high-risk pregnancies. Always consult with your obstetrician or midwife before making significant dietary changes during pregnancy, especially if you have existing health conditions, allergies, or dietary restrictions. This information is educational and should not replace personalized medical advice from your healthcare provider. Pregnant women should continue receiving regular prenatal care and follow their doctor’s recommendations.