This prospective cohort study investigates glycaemic variability, assessed by continuous glucose monitoring (CGM), in pregnant women with gestational diabetes mellitus (GDM) and its association with fetal growth and related maternal and neonatal outcomes. Participants will undergo 14 days of CGM during pregnancy to characterise individual glycaemic patterns. Clinical and paraclinical data, including fasting plasma glucose, HbA1c, lipid profile, organ markers of pregnancy-related medical conditions, maternal weight gain, and blood pressure will be collected at two study visits. Oral glucose tolerance test (OGTT) 2-hour values will be obtained at diagnosis. All participants will receive standard GDM care and routine obstetric follow-up for assessment of fetal growth and wellbeing. Birth weight, birth weight z-scores, and relevant neonatal outcomes will be recorded after delivery. Statistical analyses will be performed using Stata statistical software (StataCorp LLC, College Station, TX, USA). Continuous and categorical variables will be summarised using appropriate descriptive statistics. Associations between maternal glycaemic variability and neonatal as well as other maternal metabolic outcomes will be explored using suitable statistical methods, with adjustment for relevant covariates. Exploratory analyses may include additional glycaemic variability metrics and lipid parameters to further characterise maternal metabolic patterns.