Metabolic status in mothers with gestational diabetes mellitus and the effects on fetal and neonatal outcomes – a cohort study

BACKGROUND: Research on gestational diabetes mellitus has mainly focused on glucose metabolism, but improving glycemic control has not eliminated the complication rate in these pregnancies. The aim of this study was therefore to investigate how other metabolic and cardiovascular risk factors in women with gestational diabetes mellitus contribute to adverse pregnancy outcomes, thereby giving a more nuanced characterization of maternal metabolic status and the effects on fetal outcome. METHODS: This cohort study included mother-infant pairs with maternal gestational diabetes mellitus (n = 722) in the Central Region of Denmark from 2019 to 2022. Anthropometric and metabolic data were collected during a pregnancy visit at week 34-38. Offspring data were collected from an audit of the participants' medical records. Large for gestational age (LGA) was defined as birth weight above the 90th centile for gestational age and sex. Logistic and linear regression were performed to determine the association between maternal metabolic cardiovascular risk factors and adverse pregnancy outcomes. Analyses were adjusted for age, ethnicity, and parity. Exposures unrelated to weight were adjusted for pregestational body mass index. Furthermore, outcome rates were stratified by treatment (insulin vs. diet-only). RESULTS: (adjusted odds ratio (aOR)) = 2.26 [1.37;3.73]), increasing diagnostic oral glucose tolerance test 2-h glucose value (aOR = 1.20 [1.05;1.38]), 3rd trimester total cholesterol (aOR = 1.25 [1.05;1.49]), 3rd trimester triglycerides (aOR = 1.28 [1.07;1.53]), 3rd trimester HbA1c (aOR = 1.13 [1.07;1.18]), high gestational weight gain (aOR = 1.76 [1.07;2.87]), and insulin-treatment compared to diet-only treatment (risk ratio = 2.51[1.89;3.33]). CONCLUSION: Strong associations between pre-pregnancy body mass index, glycemic measures, and lipid profiles with adverse neonatal outcomes, particularly large for gestational age, underscore the importance of a broader risk assessment in women with gestational diabetes mellitus, not only based on glycemic parameters but also including weight prior to and during pregnancy and lipid status.