Aim: This study aimed to examine dietary intake and decision-making in a cohort of pregnant South-East Queensland women to determine compliance with dietary guidelines and the relationships between dietary intake, decision-making and birth outcomes. Methods: Pregnant women attending maternity services at participating hospitals reported food frequency and motivations using the Maternal Outcomes and Nutrition Tool, a novel digital instrument. Birth outcomes were sourced from hospital records. A cross-sectional cohort design was used to examine the data. Results: Analysis demonstrated suboptimal intake of core food groups; meat and alternatives (median [IQR]) (2.6 [2.0-3.4] serves/day) and grains (3.1 [2.1-4.1]) fell below recommendations; fruit (3.8 [2.5-5.3]) and discretionary foods (3.1 [2.1-4.4]) exceeded them. Hypertensive disorders demonstrated a negative linear relationship with vegetable intake (P =.017). Cultural diversity was significantly associated with decreased birthweight (P =.022) but increased intake of meat and alternatives (3.1 vs 2.6, P <.001) compared to Caucasian women; median intake of meat and alternatives was lower in women who reported smoking in the examined time frame. Smokers were less likely to declare health motives for food selection than non-smokers; smoking and health were inversely associated with increasing maternal age. Food choice was primarily sensory-driven. Conclusions: This cohort demonstrated poor adherence to dietary guidelines. Culturally and linguistically diverse women and smokers exhibit dietary behaviours which may contribute to suboptimal birth outcomes; targeted nutrition counselling may improve outcomes in these women. These findings highlight the need for transdisciplinary maternity care and provide a foundation for further research aimed at optimising nutrition-related birth outcomes in at-risk groups.