Glucose Levels of the Oral Glucose Tolerance Test (oGTT) Can Predict Adverse Pregnancy Outcomes in Women with Gestational Diabetes (GDM)

Abstract

Objectives and Background: Gestational diabetes (GDM) is a common pregnancy complication defined as a glucose intolerance diagnosis during pregnancy. GDM is strongly associated with adverse fetal and maternal outcomes. In Germany, to screen and diagnose GDM we use a 1 h 50 g oGCT (oral glucose challenge test) followed by a 2 h 75 g oGTT if the first was pathological. This analysis examines the correlation of 75 g oGTT glucose levels and fetomaternal outcome. Methods: Data from 1664 patients from a gestational diabetes consultation clinic at the Charité University Hospital in Berlin, Germany, were analyzed retrospectively from 2015 to 2022. The 75 g oGTT blood glucose levels were categorized into isolated fasting hyperglycemia (GDM-IFH), isolated post-load hyperglycemia (GDM-IPH) and combined hyperglycemia (GDM-CH), using the levels of the fasting, 1 h and 2 h values, after glucose application. These subtypes were compared based on their baseline characteristics as well as fetal and maternal outcome. Results: GDM-IFH and GDM-CH women displayed higher pre-conceptional BMI and required insulin therapy more frequently (p < 0.001). The GDM-IFH group was at higher risk of having a primary cesarean section (p = 0.047), while GDM-IPH women were significantly more likely to have an emergent cesarean section (p = 0.013). The offspring of GDM-IFH and GDM-CH women were born with a significantly higher mean birthweight (p < 0.001) and birth weight percentiles (p < 0.001) and were at increased risk of being large for gestational age (LGA) (p = 0.004). Women from the GDM-IPH group delivered significantly more neonates who were small for gestational age (p = 0.027) or with low fetal weight <30th percentile (p = 0.003). Conclusion: This analysis shows a strong association between the glucose response pattern in the 75 g oGTT and adverse perinatal fetomaternal outcome. The differences among the subgroups, specifically concerning insulin therapy, mode of delivery and fetal growth, suggest an individualized approach to prenatal care after a GDM diagnosis.

Dietary Intake and Oral Glucose Tolerance Test Results in Women with Gestational Diabetes

“…This approach is innovative and aligns with the recent concept that GDM is a disease with different phenotypes [57]. Several investigators suggest the existence of different metabolic subtypes of GDM, possibly associated with better or worse maternal/perinatal outcomes, which could be identified based on GTT results [14][15][16][58][59][60][61][62]. The study has several limitations.…”

Post‐load glucose is a stronger predictor of adverse pregnancy outcomes than first‐trimester HbA1c in women without gestational diabetes

“…Meanwhile, the association of HbA1c in the first trimester with adverse pregnancy outcomes is still a topic of debate 14 . An oral glucose tolerance test is used to screen and diagnose gestational diabetes mellitus after 24 weeks of gestation 15 . Studies have been focused on the relationship between oral glucose tolerance test and adverse pregnancy outcomes in women with gestational diabetes mellitus 15 .…”

“…An oral glucose tolerance test is used to screen and diagnose gestational diabetes mellitus after 24 weeks of gestation 15 . Studies have been focused on the relationship between oral glucose tolerance test and adverse pregnancy outcomes in women with gestational diabetes mellitus 15 . However, more research is needed to answer the question of whether post‐load glucose levels are associated with adverse pregnancy outcomes in women without gestational diabetes mellitus.…”

The CHANGED Score—A New Tool for the Prediction of Insulin Dependency in Gestational Diabetes

“…However, it can be difficult to foresee the course of disease based on the first consultation and the oral glucose tolerance tests performed at this point. Recent investigations have characterized different manifestations of disease, or so-called metabolic types, depending on the response to the 75 g oral glucose tolerance test (oGTT) [20,21]. It may be possible to utilize these findings by including oGTT patterns, as well as known risk factors, into a new prediction model that clinicians can apply to improve the identification at an early point of pregnancy of patients at risk of iGDM, thereby being able to optimize and individualize treatment plans.…”