Gestational diabetes mellitus (GDM) is the most common cause of hyperglycemia in pregnancy, a condition with rising incidence in recent years alongside obesity, diabetes, and cardiovascular disease. GDM carries the risk of later health complications for both the mother (in terms of developing obesity, diabetes, hypertension, and other cardiovascular issues) and the child (disorders of neurological, cardiovascular, and respiratory system development, slower growth, higher risk of obesity later in life). It is speculated that a history of GDM may serve as a risk factor for the later development of metabolic syndrome (MetS) in women. Over the past ten years, several long-term studies have been conducted with the aim of confirming this hypothesis. The conclusions of the studies indicate that there is a statistically significant association between GDM and MetS, with a notable predictive significance of other factors: those before pregnancy such as abdominal obesity and those during pregnancy such as low plasma adiponectin levels. Other research on the topic of the association between GDM and MetS suggests ways to reduce the risk of developing later complications, such as vitamin D, zinc, and calcium co-suplementation along with adhering to a "Mediterranean" diet. It is of great importance to mitigate the consequences of a pregnancy burdened by GDM by scheduling more frequent check-ups and providing useful and ongoing advice to women at risk.