Women with gestational diabetes mellitus exhibit a distinct temporal pattern of glucagon-like peptide-1 response during an oral glucose tolerance test, according to a matched nested case-control study published in Diabetology & Metabolic Syndrome. The research, led by Yangying Wu and colleagues, indicates that while absolute circulating levels of this incretin hormone do not differ significantly between women with gestational diabetes and those with normal glucose tolerance, the shape of the response curve over time is markedly different.
The study addressed a gap in understanding where previous findings regarding circulating GLP-1 in gestational diabetes have been inconsistent.
The investigation was nested within a larger cohort of pregnant women undergoing the standard 75-gram oral glucose tolerance test. The analysis included 154 women diagnosed with gestational diabetes mellitus and 154 women with normal glucose tolerance, creating a matched case-control design. Researchers measured plasma glucose, insulin, and total GLP-1 concentrations at three specific intervals: fasting, one hour after glucose ingestion, and two hours after ingestion. This design allowed for a direct comparison of the hormonal responses between the two groups under identical testing conditions.
Statistical analysis employed linear mixed-effects models to compare the temporal profiles of GLP-1 between the groups. The results showed that absolute GLP-1 concentrations did not differ significantly between the gestational diabetes group and the normal glucose tolerance group at any of the measured time points. However, a significant interaction between time and gestational diabetes status was observed, with a P-value of 0.016, indicating that the trajectory of the hormone changed differently over time for the two groups.
The temporal pattern revealed an upward trend in GLP-1 levels in women with normal glucose tolerance, whereas women with gestational diabetes displayed a relatively flat pattern across the measured time points. The study also evaluated exploratory ratios of GLP-1 area under the curve to glucose area under the curve and to insulin area under the curve. Both of these denominator-dependent ratios were significantly lower in the gestational diabetes group compared to the normal glucose tolerance group, with adjusted P-values less than 0.001 for both comparisons.
When examining specific glycemic phenotypes, the researchers categorized participants into normal glucose tolerance, isolated fasting hyperglycemia, isolated post-load hyperglycemia, and combined hyperglycemia. The absolute GLP-1 area under the curve did not differ among these four phenotypes. However, the exploratory ratios of GLP-1 to glucose and GLP-1 to insulin were lower in the isolated post-load and combined hyperglycemia groups than in the normal glucose tolerance group. In contrast, these ratios did not differ significantly between the isolated fasting hyperglycemia group and the normal glucose tolerance group, nor were there significant differences in direct pairwise comparisons among the various hyperglycemia phenotypes for either ratio.
The study also assessed the relationship between GLP-1 measures and broader metabolic indices, finding only negligible to weak correlations. Regarding pregnancy outcomes, no GLP-1-related measure was independently associated with the evaluated outcomes after applying false discovery rate correction for multiple testing. The authors emphasized that the limited number of obstetric events in the cohort precluded the ability to exclude clinically relevant associations with pregnancy outcomes, a limitation that must be considered when interpreting the lack of significant findings in this domain.
The authors explicitly stated that the denominator-dependent ratios, such as GLP-1 area under the curve divided by glucose or insulin area under the curve, should not be interpreted as validated measures of GLP-1 secretion, responsiveness, or overall incretin function.
Subject of Research: Temporal GLP-1 response patterns in gestational diabetes mellitus
Article Title: Altered relative GLP-1 response patterns in gestational diabetes mellitus: a matched nested case-control study
Article References: Wu, Y., Luo, P., Qin, K., Lin, Z., Yang, Y., Gao, X., & Mei, B. (2026). Altered relative GLP-1 response patterns in gestational diabetes mellitus: a matched nested case-control study. Diabetology & Metabolic Syndrome. https://doi.org/10.1186/s13098-026-02303-z
Image Credits: AI Generated
DOI: 10.1186/s13098-026-02303-z
Keywords: gestational diabetes, GLP-1, incretin function, oral glucose tolerance test, case-control study, pregnancy outcomes, metabolic syndrome, glycemic phenotypes, Altered, relative, response, patterns
News Source: Ophelia Keating. (November 9, 2026). GDM Shows Flat GLP-1 Response During Glucose Test. Scienmag.
