Adherence to four plant-based dietary patterns and associated factors during pregnancy: the INfancia and Medio Ambiente cohort study.

PROPOSE: This study examined adherence to four plant-based dietary patterns (PBDP) and identified sociodemographic and lifestyle predictors among pregnant women.

METHODS

We analysed data from 2,404 participants of the INMA birth cohort study. Dietary intake was assessed using validated food-frequency questionnaires administered in the first and third trimesters. General pro-vegetarian (gPVG), healthful (hPVG), unhealthful (uPVG) dietary patterns and the relative Mediterranean Diet score (rMED) were categorized into tertiles. First tertile was the reference category. Multinomial logistic regression models estimated relative risk ratios (RRR) and 95% confidence intervals (95%CI) to assess predictors of adherence to each PBDP.

RESULTS

Among participants, 61.2% aged ≥30 years, 34.3% had a university degree, and 31.6% reported smoking at the start of pregnancy. Older age (≥ 30 years) was positively associated with hPVG [RRR=2.04 (95%CI: 1.63-2.55)] and rMED [RRR=1.55 (95%CI: 1.25-1.92)], and inversely associated with uPVG [RRR=0.48 (95%CI: 0.39-0.60)]. Higher educational level was inversely associated with gPVG [RRRuniversity=0.69 (95%CI: 0.50-0.96)] and uPVG [RRRuniversity=0.54 (95%CI: 0.38-0.77)], whereas higher social class showed positive associations with gPVG [RRRhigh=1.45 (95%CI: 1.07-1.97)] and rMED [RRRhigh=1.43 (95%CI: 1.04-1.98)]. Latin American origin was positively associated with gPVG and uPVG. Smoking at pregnancy onset was inversely associated with hPVG and rMED, but positively associated with uPVG. Higher physical activity in the first trimester was positively associated with healthier patterns (gPVG, hPVG, rMED) and inversely associated with uPVG.

CONCLUSION

Adherence to healthier PBDP was more common among older, more active and non-smoking women, whereas the uPVG pattern clustered among younger, less educated, less physically active, Latin American and smoking women. These findings may help identify population subgroups for targeted nutritional interventions aimed at improving diet quality during this sensitive life stage.