Gestational diabetes mellitus (GDM) traditionally refers to abnormal glucose tolerance with onset or first recognition during pregnancy. GDM has long been associated with obstetric and neonatal complications primarily relating to higher infant birthweight and is increasingly recognized as a risk factor for future maternal and offspring cardiometabolic disease. The prevalence of GDM continues to rise internationally due to epidemiological factors including the increase in background rates of obesity in women of reproductive age and rising maternal age and the implementation of the revised International Association of the Diabetes and Pregnancy Study Groups’ criteria and diagnostic procedures for GDM. The current lack of international consensus for the diagnosis of GDM reflects its complex historical evolution and pragmatic antenatal resource considerations given GDM is now 1 of the most common complications of pregnancy. Regardless, the contemporary clinical approach to GDM should be informed not only by its short-term complications but also by its longer term prognosis. Recent data demonstrate the effect of early in utero exposure to maternal hyperglycemia, with evidence for fetal overgrowth present prior to the traditional diagnosis of GDM from 24 weeks’ gestation, as well as the durable adverse impact of maternal hyperglycemia on child and adolescent metabolism. The major contribution of GDM to the global epidemic of intergenerational cardiometabolic disease highlights the importance of identifying GDM as an early risk factor for type 2 diabetes and cardiovascular disease, broadening the prevailing clinical approach to address longer term maternal and offspring complications following a diagnosis of GDM.

OBJECTIVE Recent guidelines recommend testing at <24 weeks of gestation for maternal dysglycemia in “high-risk” women. Evidence to support the early identification and treatment of gestational diabetes mellitus (GDM) is, however, limited. We examined the prevalence, clinical characteristics, and pregnancy outcomes of high-risk women with GDM diagnosed at <24 weeks of gestation (early GDM) and those with pre-existing diabetes compared with GDM diagnosed at ≥24 weeks of gestation, in a large treated multiethnic cohort. RESEARCH DESIGN AND METHODS Outcomes from 4,873 women attending a university hospital antenatal diabetes clinic between 1991 and 2011 were examined. All were treated to standardized glycemic targets. Women were stratified as pre-existing diabetes (n = 65) or GDM diagnosed at <12 weeks of gestation (n = 68), at 12–23 weeks of gestation (n = 1,247), or at ≥24 weeks of gestation (n = 3,493). RESULTS Hypertensive disorders in pregnancy including pre-eclampsia, preterm delivery, cesarean section, and neonatal jaundice (all P < 0.001) were more prevalent in women with pre-existing diabetes and early GDM. Macrosomia (21.8% vs. 20.3%, P = 0.8), large for gestational age (39.6% vs. 32.8%, P = 0.4), and neonatal intensive care admission (38.5% vs. 39.7%, P = 0.9) in women in whom GDM was diagnosed at <12 weeks of gestation were comparable to rates seen in women with pre-existing diabetes. CONCLUSIONS Despite early testing and current best practice treatment, early GDM in high-risk women remains associated with poorer pregnancy outcomes. Outcomes for those in whom GDM was diagnosed at <12 weeks of gestation approximated those seen in pre-existing diabetes. These findings indicate the need for further studies to establish the efficacy of alternative management approaches to improve outcomes in these high-risk pregnancies.

The original nutrition approach for the treatment of gestational diabetes mellitus (GDM) was to reduce total carbohydrate intake to 33–40% of total energy (EI) to decrease fetal overgrowth. Conversely, accumulating evidence suggests that higher carbohydrate intakes (60–70% EI, higher quality carbohydrates with low glycemic index/low added sugars) can control maternal glycemia. The Institute of Medicine (IOM) recommends ≥175 g/d of carbohydrate intake during pregnancy; however, many women are consuming lower carbohydrate (LC) diets (<175 g/d of carbohydrate or <40% of EI) within pregnancy and the periconceptual period aiming to improve glycemic control and pregnancy outcomes. This report systematically evaluates recent data (2018–2020) to identify the LC threshold in pregnancy in relation to safety considerations. Evidence from 11 reports suggests an optimal carbohydrate range of 47–70% EI supports normal fetal growth; higher than the conventionally recognized LC threshold. However, inadequate total maternal EI, which independently slows fetal growth was a frequent confounder across studies. Effects of a carbohydrate intake <175 g/d on maternal ketonemia and plasma triglyceride/free fatty acid concentrations remain unclear. A recent randomized controlled trial (RCT) suggests a higher risk for micronutrient deficiency with carbohydrate intake ≤165 g/d in GDM. Well-controlled prospective RCTs comparing LC (<165 g/d) and higher carbohydrate energy-balanced diets in pregnant women are clearly overdue.

Objective: We examined whether first trimester aneuploidy and pre-eclampsia screening markers predict gestational diabetes mellitus (GDM) in a large multi-ethnic cohort and the influence of local population characteristics on markers. Methods: Clinical and first trimester markers (mean arterial pressure (MAP), uterine artery pulsatility index (UtA PI), pregnancy associated plasma protein A (PAPP-A), free-β human chorionic gonadotropin (free-hCGβ)) were measured in a case-control study of 980 women (248 with GDM, 732 controls) at 11 to 13 + 6 weeks’ gestation. Clinical parameters, MAP-, UtA PI-, PAPP-A-, and free-hCGβ-multiples-of-the-median (MoM) were compared between GDM and controls; stratified by ethnicity, parity, and GDM diagnosis <24 versus ≥24 weeks’ gestation. GDM model screening performance was evaluated using AUROC. Results: PAPP-A- and UtA PI-MoM were significantly lower in GDM versus controls (median ((IQR) PAPP-A-MoM 0.81 (0.58–1.20) versus 1.00 (0.70–1.46); UtA PI-MoM 1.01 (0.82–1.21) versus 1.05 (0.84–1.29); p < .05). Previous GDM, family history of diabetes, south/east Asian ethnicity, parity, BMI, MAP, UtA PI, and PAPP-A were significant predictors in multivariate analysis (p < .05). The AUC for a model based on clinical parameters was 0.88 (95%CI 0.85–0.92), increasing to 0.90 (95%CI 0.87–0.92) with first trimester markers combined. The combined model best predicted GDM <24 weeks’ gestation (AUC 0.96 (95%CI 0.94–0.98)). Conclusions: Addition of aneuploidy and pre-eclampsia markers is cost-effective and enhances early GDM detection, accurately identifying early GDM, a high-risk cohort requiring early detection, and intervention. Ethnicity and parity modified marker association with GDM, suggesting differences in pathophysiology and vascular risk.

Article published by the Endocrine Society Article published by the Endocrine Society