The utility of early gestational OGTT and biomarkers for the development of gestational diabetes mellitus: an international prospective multicentre cohort study

There is no clear consensus regarding accurate risk stratification in early pregnancy for later developing gestational diabetes mellitus (GDM). Therefore, this study aims to evaluate the predictive performance of an OGTT and several biomarkers in the first trimester of pregnancy. Their association with insulin action, beta cell function and requirement for insulin were additionally assessed. In this prospective cohort study, we included 657 pregnant women in six Central European centres. Patient history and anthropometric data were obtained, a blinded 75 g OGTT was performed and biochemical markers were assessed at a median gestational age of 13.4 weeks (IQR 12.7-14.1). Another OGTT was performed in later pregnancy to identify women with GDM. A detailed investigation of glucose homeostasis was performed at both visits in a subgroup of women. Eighty-three women (12.6%) developed GDM. Progression to GDM was fairly well predicted by glucose concentrations during the early OGTT in terms of areas under the receiver operating characteristic curves (OGTT glucose at fasting: 0.68; OGTT glucose at 60 min: 0.74; OGTT glucose at 120 min: 0.72). Some biomarkers showed significant but modest predictive accuracy. Early gestational OGTT glucose concentrations were further associated with impaired insulin sensitivity and beta cell dysfunction, as well as the requirement for insulin in later pregnancy. Although the accurate diagnosis of GDM before 24 weeks remains an ongoing discussion, dynamically assessed glucose concentrations during an early OGTT were closely associated with impaired glucose homeostasis and showed good predictive accuracy for later development of GDM as well as the requirement for insulin. These findings may be used to develop a protocol to distinguish between low- and high-risk mothers. Trial registration ClinicalTrials.gov NCT02035059.