Gestational Diabetes: Evaluating Diagnostic Criteria and Screening Strategies in Light of Evolving Guidelines

Abstract

Gestational diabetes mellitus (GDM) is the most common metabolic condition of pregnancy with potential lifelong implications for the health of the mother and child, extending its adverse effects into the next generation. Management of women with hyperglycemia reduces both maternal and neonatal risks and may prevent the later development of obesity, diabetes, and cardiovascular disease, highlighting the importance of identifying women with GDM. However, there is no international consensus regarding the optimal approach to screening and diagnosis of GDM. The overarching aim of this thesis was to improve GDM screening strategies by more accurately identifying women to target for testing, balancing benefits and harms for both women and their children, as well as for health care providers and society at large. Data from four Norwegian pregnancy and birth cohorts from the period 2002-2013 were merged, encompassing a total of 2981 women universally screened with a 75-g oral glucose tolerance test (OGTT). Two studies were prospective cohort studies and two were randomized controlled trials, recruiting pregnant women at mean gestational week 16.5. GDM was originally diagnosed and treated according to the World Health Organization (WHO) 1999 criteria, whereas the WHO-2013 and the Norwegian-2017 criteria were retrospectively applied to the same glucose data in the current pooled data analysis. Perinatal outcomes related to GDM, including large-for-gestational-age (LGA) infants, cesarean section, operative vaginal delivery, preterm birth and preeclampsia, were assessed using logistic regression analyses. Diagnostic accuracy analyses were performed to examine the use of fasting plasma glucose and risk factors, for detection of GDM.