The global prevalence of maternal obesity has increased dramatically, with approximately 39 million pregnancies annually complicated by maternal obesity. This review examines the multifaceted risks associated with excessive gestational weight gain and maternal obesity, exploring both established complications and emerging concerns through current research evidence. Methods: We conducted a comprehensive analysis of recent literature on maternal obesity, focusing on epidemiological trends, pathophysiological mechanisms, and clinical outcomes. The review synthesizes findings from systematic reviews, meta-analyses, and randomized controlled trials published primarily within the last decade to provide an evidence-based assessment of obesity-related pregnancy complications. Results: Maternal obesity demonstrates strong associations with numerous adverse outcomes, including fertility impairment, early pregnancy loss, hypertensive disorders, and gestational diabetes. For every 5 kg/m² increase in BMI above the ideal range, stillbirth risk increases by 24%. Obese women exhibit 3.69-fold higher risk of gestational hypertension and significantly elevated pre-eclampsia risk through mechanisms involving adiposopathy, insulin resistance, and complement system dysregulation. Labor complications include threefold higher odds of induction failure and cesarean rates reaching 52.3% in morbidly obese women. Importantly, maternal obesity programs lasting metabolic dysfunction in offspring, with effects detectable even at age 60. Conclusion: The evidence demonstrates that maternal obesity represents a significant modifiable risk factor affecting both immediate pregnancy outcomes and long-term health trajectories of mothers and offspring. While dietary interventions show greater efficacy than physical activity alone in managing gestational weight gain, intervention timing is critical, with implementation before 20 weeks’ gestation yielding superior outcomes. These findings underscore the importance of preconception counseling and early pregnancy interventions to mitigate obesity-related pregnancy complications.