Association between high fat, sugar, and sodium diet and adverse pregnancy outcomes, modified by fruit and vegetable intake density.

BACKGROUND: We aimed to examine whether fruit and vegetable intake densities modify the association between a periconceptional high-fat, sugar, and sodium diet and adverse pregnancy outcomes. METHODS: We analyzed data from 8,259 participants in the Nulliparous Pregnancy Outcomes Study: Monitoring Mothers-to-Be (2010-2013). Periconceptional diet was assessed via food frequency questionnaire. The outcome was a composite of preeclampsia, gestational diabetes, preterm birth, or small-for-gestational-age birth; individual outcomes were also examined. Effect modification by vegetable and fruit intake densities was evaluated using a doubly robust learner with ensemble machine learning. RESULTS: Approximately 23% of participants experienced an adverse outcome, and 29% consumed a high-fat, sugar, and sodium diet. This dietary pattern was associated with 1.0-2.9 excess cases per 100 pregnancies for the composite outcome and most individual outcomes (except preterm birth), compared with other diets. For the composite outcome, associations varied across levels of vegetable but not fruit intake density, although estimates were imprecise. For example, risk differences decreased from 3.7 (95% CI, -0.7 to 8.0) to 2.6 (95% CI, -1.4 to 6.6) excess cases per 100 pregnancies at 0.5 versus 1.25 cups of vegetables per 1,000 kcal. Attenuation of risk at higher vegetable intake was slightly greater when combined with higher fruit intake density, but estimates remained imprecise, limiting interpretation of joint effect modification. Patterns of associations differed across individual outcomes. CONCLUSIONS: We did not find evidence that the risk of adverse pregnancy outcomes associated with a high-fat, sugar, and sodium dietary pattern was meaningfully different across vegetable and/or fruit intake densities.