INTRODUCTION

Maternal dietary intake in the periconception period affects fertility, prenatal development and pregnancy outcome with long-lasting consequences for offspring health 1-4. In the typical Western diet, the intake of fruits, vegetables and whole grains is generally below recommended levels and the proportion of sodium, fats and carbohydrates is relatively high 5. With the global exponential increase of ultra-processed food (UPF) consumption in the last decade, the nutritional status of women has worsened4, 6, 7. Therefore, there is an urgent need to investigate how UPF consumption impacts prenatal development.
UPF, such as soft drinks, instant meals and confectionery, are produced by various processing techniques, and additives are used to produce durable, appetizing, ready-to-eat packaged foods 8. UPF differ in composition compared to less processed foods as they are generally high in energy and contain higher levels of sodium, sugars and saturated fat 9, 10. Foods rich in simple carbohydrates and saturated fatty acids are typically associated with a negative impact on overall health and promote obesity11. Indeed, several studies have shown a negative effect of high UPF consumption on multiple health domains, including an increased risk of obesity, cardiovascular disease and certain type of cancers 12, 13.
High consumption of UPF in the periconception period is associated with impaired embryonic growth, increased gestational weight gain and higher neonatal body fat 14, 15. Yet research on associations between maternal UPF consumption and obstetric outcomes are scarce and the underlying mechanisms are not fully understood. As the placenta forms the crucial link between the mother and the growing conceptus and is essential for the delivery of oxygen, energy and nutrients16, 17, we hypothesize high UPF consumption impairs the utero-placental vascular development with consequences for pregnancy outcomes and prenatal growth18.
In the present study, our primary aim is to investigate whether periconceptional maternal consumption of UPF impairs first-trimester utero-placental vascular development using recently developed imaging markers 19, 20. We further explore whether the associations can be substantiated by macronutrient intake and the adherence to specific dietary patterns.