Paradox in the research of gestational diabetes mellitus and twin pregnancies: Perspective and future directions

Gestational diabetes mellitus (GDM) is well known to be associated with fetal overgrowth and short- or long-term adverse outcomes in singleton pregnancies; however, its relationship with twin pregnancies remains controversial, posing challenges for clinical management. Despite the heterogeneity in GDM diagnosis and racial differences among populations, two critical issues remain unaddressed. The first issue is methodological, specifically whether data on twins have been analyzed using appropriate approaches. The second issue is the underlying pathophysiology'. Given that both glucose demand and insulin resistance are elevated in twin pregnancies, the optimal level of maternal insulin secretion remains uncertain. In this paper, we summarize the current knowledge on GDM in the context of twin pregnancies, their perinatal outcomes, glucose control, and gestational weight gain management. We then propose methodological considerations for future improvements. Ultimately, we underscore the importance of delving into the glucose requirements of twin pregnancies to gain a profound understanding of their gestational glucose and insulin metabolism. All these questions are key issues in this area, and by answering them we will accelerate the development of high-quality, evidence-based clinical guidelines for GDM management in twin pregnancies.