Independent and synergistic effects of OGTT-based hyperglycemia phenotypes and gestational weight gain on feto-maternal outcomes in GDM

Gestational weight gain (GWG) and hyperglycemia identified via the oral glucose tolerance test (OGTT) are critical factors influencing adverse pregnancy outcomes. However, the applicability of universal management standards for these factors across specific patient populations remains a subject of critical clinical inquiry. The objective of this study is to examine the independent and synergistic effects of different OGTT-based hyperglycemia phenotypes and GWG on adverse feto-maternal outcomes in women with GDM. From a total cohort of 52,942 parturients, this study included 5,593 cases of GDM after applying exclusion criteria. Participants were classified based on 75-g OGTT results and GWG categories. We systematically performed univariate analysis, multivariate logistic regression analysis, and interaction analysis to explore the associations between OGTT-based hyperglycemia phenotypes, GWG groups, and the incidence of adverse feto-maternal outcomes. The incidence of adverse outcomes differed significantly by hyperglycemia phenotypes and GWG categories. Importantly, interaction analysis revealed that the impact of GWG on adverse outcomes varied significantly across different hyperglycemia phenotypes. The risks of preeclampsia, hyperlipidemia, polyhydramnios, large for gestational age infants, and cesarean section were highest in the combined hyperglycemia phenotype. Our findings indicate phenotype-specific epidemiological associations with feto-maternal outcomes. Given the retrospective nature of this study, these observational data are strictly hypothesis-generating. They raise the hypothesis that exploring refined GWG targets—particularly for the isolated fasting hyperglycemia phenotype—warrants future prospective investigation. Furthermore, inadequate GWG was associated with a higher risk of preterm birth exclusively in the isolated post-load hyperglycemia phenotype, indicating a specific correlational trend that merits further exploratory research.