Gestational glycaemia reflects lifelong glycaemia: the Pune Maternal Nutrition Study

Abstract

Traditionally, gestational diabetes mellitus (GDM) (defined here as hyperglycaemia first detected during pregnancy) has been considered to be a transient condition of pregnancy, but evidence suggests it is often a pre-existing chronic condition. Studies have reported that women diagnosed with GDM were hyperglycaemic, obese and insulin-resistant from before pregnancy. However, little is known about the life-course evolution of glycaemia before pregnancy. Participants in the Pune Maternal Nutrition Study (PMNS) birth cohort underwent serial measurements of glycaemia from early childhood, through puberty, young adulthood, pregnancy and later, providing a unique opportunity to test the hypothesis that pregnancy glycaemia (fasting plasma glucose and/or OGTT AUC) is only a window on a lifetime glycaemic trajectory. Female participants in the PMNS birth cohort, established in 1993, underwent serial glucose measurements at ages 6, 12 and 18 years, and during pregnancy and post-delivery follow-up. Of 366 female cohort members, 171 became pregnant and delivered by February 2020. Given the small number of GDM cases (n=20, IADPSG criteria), we divided women into quartiles of fasting plasma glucose (FPG) and AUC during an OGTT at 28 weeks' gestation to study life-course tracking of pregnancy glycaemia. In this cohort of rural lean Indian women, higher pregnancy glycaemia reflects persistently higher glycaemia since childhood. Coupled with the existing evidence that women with GDM have higher glycaemia from before pregnancy, our results suggest that pregnancy hyperglycaemia is only a window on a life-course of hyperglycaemia and not a de novo phenomenon. This has implications for the timing of diagnosis and management of pregnancy hyperglycaemia (GDM).

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Affiliated Institutions

• University of Southampton GB
• MRC Lifecourse Epidemiology Unit GB
• Cytel (United States) US

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