This cluster of papers explores the impact of gestational diabetes mellitus (GDM) and related factors such as maternal obesity, hyperglycemia, and metabolic syndrome on pregnancy outcomes, fetal development, and long-term health implications for both mothers and offspring. It covers topics such as diagnosis, classification, treatment, prevention, and long-term consequences of GDM, as well as the association with type 2 diabetes and cardiovascular disease. Additionally, it investigates the influence of maternal weight gain, macrosomia, and metabolic imprinting on offspring health.