In 2020, it is estimated that 7.8% of all live births in the United States were complicated with gestational diabetes, with around 10% of all pregnancies in North America involving gestational diabetes. GDM’s prevalence has been increasing over time, likely due to the population’s rising BMI and increasing maternal age. GDM has been long associated with increased complications in pregnancy, from preeclampsia and macrosomia in the short-term, to long term ramifications including the development of type 2 diabetes mellitus, cardiovascular disease, and potential effects on the offspring, including obesity, insulin resistance, hypertension, and increased risk of autism. Additionally, as the field of epigenetics continuously grows, we are able to further elucidate epigenetic mechanisms at play in the development of GDM and how these changes may affect the offspring. In this narrative review, we have compiled recent and relative clinical studies that highlight the role epigenetics may play in the development and perpetuation of GDM, as well as its possible effects on the offspring.

Background: Gestational diabetes is a common complication during pregnancy that can lead to numerous adverse outcomes. Some studies suggest that probiotics may be used to treat gestational diabetes, however, the results remain controversial. We conducted a systematic review and meta-analysis to evaluate the effect of probiotics on blood glucose and pregnancy outcomes in women with gestational diabetes. Methods: A systematic search of PubMed, Embase, and Cochrane databases was performed (start date to August 22, 2023). Primary outcomes included fasting blood sugar (FBS), fasting serum insulin (FSI), homeostasis model assessment of insulin resistance (HOMA-IR), and quantitative insulin sensitivity check index (QUICKI). Secondary outcomes included pregnancy and neonatal outcomes. Results: 15 articles (n = 1006 women) met the inclusion criteria and were included in the analysis. Compared to a placebo, probiotics can decrease FBS (MD -2.58, 95% CI -4.38 to -0.79, p < 0.01), FSI (MD -2.29, 95% CI -3.40 to -1.18, p < 0.01), HOMA-IR (MD -0.56, 95% CI -0.81 to -0.32, p < 0.01), birthweight (MD -101.20, 95% CI -184.62 to -17.77, p = 0.02), neonatal intensive care unit (NICU) (RR 0.60, 95% CI 0.40 to 0.89, p = 0.01), and hyperbilirubinemia (RR 0.31, 95% CI 0.16 to 0.61, p < 0.01), alongside higher QUICKI (MD 0.01, 95% CI 0.00 to 0.01, p < 0.01). However, no other significant results were obtained. Conclusion: Probiotics may improve blood glucose indicators and reduce neonatal hyperbilirubinemia, NICU admissions, and birth weight in women with GDM.

Placental hypervascularization has been reported in pregnancy-related pathologies such as gestational diabetes mellitus (GDM). Nevertheless, the underlying causes behind this abnormality are not well understood. In this study, we addressed the expression of SUCNR1 (cognate succinate receptor) in human placental endothelial cells and hypothesized that succinate-SUCNR1 axis might play a role in the placental hypervascularization reported in GDM. We measured significantly higher succinate levels in placental tissue lysates from women with GDM relative to matched controls. In parallel, SUCNR1 protein expression was upregulated in GDM tissue lysates as well as in isolated diabetic fetoplacental arterial endothelial cells (FpECAds). A positive correlation of SUCNR1 and vascular endothelial growth factor (VEGF) protein levels in tissue lysates indicated a potential link between succinate-SUCNR1 axis and placental angiogenesis. In our in-vitro experiments, succinate prompted hallmarks of angiogenesis in human umbilical vein endothelial cells (HUVECs) such as proliferation, migration and spheroid sprouting. These results were further validated in fetoplacental arterial endothelial cells (FpECAs), where succinate induced endothelial tube formation. VEGF gene expression was increased in response to succinate in both HUVECs and FpECAs. Yet, knockdown of SUCNR1 in HUVECs led to suppression of VEGF gene expression and abrogated the migratory ability and wound healing in response to succinate. In conclusion, our data underline SUCNR1 as a promising metabolic target in human placenta and as a potential driver of enhanced placental angiogenesis in GDM.

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-hour 50g oGCT (oral glucose challenge test) followed by a 2-hour 75g oGTT if the first was pathological. This analysis examines the correlation of 75g oGTT glucose levels and fetomaternal outcome. Methods: Data of 1664 patients from a gestational diabetes consultation clinic at the Charité University hospital in Berlin, Germany, were analyzed retrospectively from 2015 until 2022. The 75g 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-hour and 2-hour values after glucose application. These subtypes were compared regarding baseline characteristics as well as fetal and maternal outcome. Results: GDM-IFH and GDM-CH women displayed higher preconceptional 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 glucose response pattern in the 75g 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 in prenatal care after a GDM diagnosis.