Diets rich in saturated fats have become a staple globally. Fifty percent of women of childbearing age in the United States are obese or overweight, with diet being a significant contributor. There is increasing evidence of the impact of maternal high-fat diet on the offspring microbiome. Alterations of the neonatal microbiome have been shown to be associated with multiple morbidities, including the development of necrotizing enterocolitis, atopy, asthma, metabolic dysfunction, and hypertension among others. This review provides an overview of the recent studies and mechanisms being examined on how maternal diet can alter the immune response and microbiome in offspring and the implications for directed public health initiatives for women of childbearing age. IMPACT: Maternal diet is important in shaping the offspring microbiome and neonatal immune system.Reviews the current literature in the field and suggests potential mechanisms and areas of research to be targeted.Highlights the current scope of our knowledge of ideal nutrition during pregnancy and consideration for enhanced public health initiatives to promote well-being of the future generation.Fig. 1POTENTIAL MECHANISMS FOR MATERNAL DIET-MEDIATED EFFECTS ON THE FETUS AFFECTING POSTNATAL COLONIZATION AND IMMUNITY.: a Maternal diet may modify the maternal microbiome resulting in altered exposure to live bacteria in utero and at birth via the vaginal canal or skin. b Maternal diet may alter the microbial processing of macro- and micronutrients and microbial colonization resulting in differential exposure in utero to microbial products, immunoglobulins, and cytokines. c Maternal diet can modulate the amount of beneficial and harmful dietary metabolites and dietary TLR ligands which the fetus becomes exposed to in utero. d Potential ways to maximize benefit for offspring microbiota and immune development include enhanced dietary guidelines for gravid women, probiotic supplementation, and nutraceutical supplementation either pre- or post-natally.Fig. 2MACRONUTRIENT CONSUMPTION IN WOMEN OF CHILD BEARING AGE AND RECOMMENDED RANGES IN USA.: Data compiled from the USDA and DHHS dietary intake interviews conducted yearly “What we eat in America” (WWEIA) with average protein, carbohydrate, and fat intake in women aged between 19 and 50 years (green bars) between 2015 and 2016. Red floating bars are recommendation ranges of macronutrient consumption from the ACOG, USDA, and Office of Disease Prevention and Health Promotion.