Effects of maternal Mediterranean diet on fetal cardiac function in high-risk pregnancies: a secondary analysis of the IMPACT BCN randomized trial.

BACKGROUND

Maternal suboptimal nutrition and high stress levels are associated with altered fetal cardiovascular function.

OBJECTIVE

This study aimed to assess the effect of structured maternal lifestyle interventions based on a Mediterranean diet or mindfulness-based stress reduction during pregnancy on fetal cardiac function.

STUDY

DESIGN

This was a secondary analysis of the IMPACT BCN (Improving Mothers for a better PrenAtal Care Trial BarCeloNa) randomized clinical trial, which was conducted at a university hospital in Barcelona, Spain, from February 2017 to March 2020. A total of 1221 singleton pregnancies (19-23 weeks' gestation) with high risk of delivering small-for-gestational-age newborns were randomly allocated into 3 groups in a 1:1:1 ratio: a Mediterranean diet intervention, a stress reduction program, or usual care. Participants in the Mediterranean diet group received monthly individual and group educational sessions and free provision of extra-virgin olive oil and walnuts. Those in the stress reduction group underwent an 8-week mindfulness-based stress reduction program adapted for pregnancy. Individuals in the usual care group received pregnancy care per institutional protocols. Fetal cardiac function was assessed using cord blood NT-proBNP (N-terminal probrain natriuretic peptide) and fetal echocardiography. NT-proBNP was measured in cord blood collected at delivery and considered high if >90th centile. Fetal echocardiography was performed at 33 to 34 weeks' gestation. Data were analyzed from January to July 2024.

RESULTS

Fetal echocardiography and cord blood NT-proBNP measurements were obtained in 990 and 746 pregnancies, respectively. Whereas fetuses in the stress reduction group showed similar fetal cardiac results, the proportion of fetuses with high cord blood NT-proBNP concentrations was significantly lower in the Mediterranean diet group (6.4% vs 12%; P=.03) compared with the usual care group. Additionally, fetuses whose mothers followed the Mediterranean diet exhibited higher right ventricular fractional area change (mean [standard deviation], 30.4% [8.3] vs 28.1% [8.9]; P=.03) and thinner myocardial walls (mean [standard deviation], 2.95 [0.55] vs 3.16 [0.58] mm; P=.006) compared with the usual care group.

CONCLUSION

Promotion of a maternal Mediterranean diet intervention during pregnancy seems to be associated with a less overloaded and more efficient fetal heart. Future research is warranted to elucidate the mechanism(s) underlying these findings.