To Örebro University

OBJECTIVE: To investigate the association of timing of commencing glucose management with glycemia, glycemic variability, and pregnancy outcomes among women with early gestational diabetes mellitus (GDM).

RESEARCH DESIGN AND METHODS: In this substudy among participants of a trial of immediate vs delayed treatment of early GDM diagnosed by 2013 World Health Organization criteria, all women treated immediately and those with delayed diagnosis at 24-28 weeks' gestation (treated as if late GDM) were instructed to monitor capillary blood glucose (BG) four times a day (fasting and 2-h postprandial) until delivery. Optimal glycemia was defined as ≥95% of BG measurements between 70 and 140 mg/dL (3.9-7.8 mmol/L).

RESULTS: Overall, 107,716 BG values were obtained from 329 of 549 (59.9%) women (mean age 32.3 ± 4.9 years, BMI 32.0 ± 8.0 kg/m2, 35% European, gestation at GDM diagnosis 15.2 ± 2.4 weeks). Women treated early (n = 213) showed lower mean glucose (MG) and mean fasting glucose (MFG) compared with those treated late (n = 116) (MG: 5.7 ± 0.4 vs. 5.9 ± 0.5, P < 0.001; MFG: 5.2 ± 0.3 vs. 5.3 ± 0.4, P = 0.004), with greater optimal glycemia (74.6% vs. 59.5%, P = 0.006) and similar glycemic variability. MG was similar from 30 weeks' gestation. Overall, optimal glycemia was achieved in 69% of women and associated with lower birth weight, fewer large-for-gestational-age infants (14.4% vs. 26.7%, P = 0.01), more small-for-gestational-age infants (15.3% vs. 5.9%, P = 0.02), and lower gestational weight gain (4.9 ± 6.4 vs. 7.6 ± 6.2 kg, P = 0.001). Suboptimal glycemia was associated with non-European ethnicity, prior GDM, 1-h glucose at booking oral glucose tolerance test, and insulin use.

CONCLUSIONS: Both early and delayed treatment of early GDM resulted in similar glycemia toward the end of pregnancy. Early treatment was associated with improved glycemia overall.

Gestational diabetes remains the most common medical disorder in pregnancy, with short-term and long-term consequences for mothers and offspring. New insights into pathophysiology and management suggest that the current gestational diabetes treatment approach should expand from a focus on late gestational diabetes to a personalised, integrated life course approach from preconception to postpartum and beyond. Early pregnancy lifestyle intervention could prevent late gestational diabetes. Early gestational diabetes diagnosis and treatment has been shown to be beneficial, especially when identified before 14 weeks of gestation. Early gestational diabetes screening now requires strategies for integration into routine antenatal care, alongside efforts to reduce variation in gestational diabetes care, across settings that differ between, and within, countries. Following gestational diabetes, an oral glucose tolerance test should be performed 6-12 weeks postpartum to assess the glycaemic state. Subsequent regular screening for both dysglycaemia and cardiometabolic disease is recommended, which can be incorporated alongside other family health activities. Diabetes prevention programmes for women with previous gestational diabetes might be enhanced using shared decision making and precision medicine. At all stages in this life course approach, across both high-resource and low-resource settings, a more systematic process for identifying and overcoming barriers to preventative care and treatment is needed to reduce the current global burden of gestational diabetes.

BACKGROUND: The World Health Organisation (WHO) 2013 diagnostic criteria for gestational diabetes mellitus (GDM) has been criticised due to the limited evidence of benefits on pregnancy outcomes in different populations when switching from previously higher glycemic thresholds to the lower WHO-2013 diagnostic criteria. The aim of this study was to determine whether the switch from previous Swedish (SWE-GDM) to the WHO-2013 GDM criteria in Sweden following risk factor-based screening improves pregnancy outcomes.

METHODS AND FINDINGS: A stepped wedge cluster randomised trial was performed between January 1 and December 31, 2018 in 11 clusters (17 delivery units) across Sweden, including all pregnancies under care and excluding preexisting diabetes, gastric bypass surgery, or multifetal pregnancies from the analysis. After implementation of uniform clinical and laboratory guidelines, a number of clusters were randomised to intervention (switch to WHO-2013 GDM criteria) each month from February to November 2018. The primary outcome was large for gestational age (LGA, defined as birth weight >90th percentile). Other secondary and prespecified outcomes included maternal and neonatal birth complications. Primary analysis was by modified intention to treat (mITT), excluding 3 clusters that were randomised before study start but were unable to implement the intervention. Prespecified subgroup analysis was undertaken among those discordant for the definition of GDM. Multilevel mixed regression models were used to compare outcome LGA between WHO-2013 and SWE-GDM groups adjusted for clusters, time periods, and potential confounders. Multiple imputation was used for missing potential confounding variables. In the mITT analysis, 47 080 pregnancies were included with 6 882 (14.6%) oral glucose tolerance tests (OGTTs) performed. The GDM prevalence increased from 595/22 797 (2.6%) to 1 591/24 283 (6.6%) after the intervention. In the mITT population, the switch was associated with no change in primary outcome LGA (2 790/24 209 (11.5%) versus 2 584/22 707 (11.4%)) producing an adjusted risk ratio (aRR) of 0.97 (95% confidence interval 0.91 to 1.02, p = 0.26). In the subgroup, the prevalence of LGA was 273/956 (28.8%) before and 278/1 239 (22.5%) after the switch, aRR 0.87 (95% CI 0.75 to 1.01, p = 0.076). No serious events were reported. Potential limitations of this trial are mainly due to the trial design, including failure to adhere to guidelines within and between the clusters and influences of unidentified temporal variations.

CONCLUSIONS: In this study, implementing the WHO-2013 criteria in Sweden with risk factor-based screening did not significantly reduce LGA prevalence defined as birth weight >90th percentile, in the total population, or in the subgroup discordant for the definition of GDM. Future studies are needed to evaluate the effects of treating different glucose thresholds during pregnancy in different populations, with different screening strategies and clinical management guidelines, to optimise women's and children's health in the short and long term.

TRIAL REGISTRATION: The trial is registered with ISRCTN (41918550).

BACKGROUND: A recently undertaken multicenter randomized controlled trial (RCT) "Treatment Of BOoking Gestational diabetes Mellitus" (TOBOGM: 2017-2022) found that the diagnosis and treatment of pregnant women with early gestational diabetes mellitus (GDM) improved pregnancy outcomes. Based on data from the trial, this study aimed to assess the cost-effectiveness of diagnosis and treatment of early GDM (from <20 weeks') among women with risk factors for hyperglycemia in pregnancy compared with usual care (no treatment until 24-28 weeks') from a healthcare perspective.

METHODS: Participants' healthcare resource utilization data were collected from their self-reported questionnaires and hospital records, and valued using the unit costs obtained from standard Australian national sources. Costs were reported in US dollars ($) using the purchasing power parity (PPP) estimates to facilitate comparison of costs across countries. Intention-to-treat (ITT) principle was followed. Missing cost data were replaced using multiple imputations. Bootstrapping method was used to estimate the uncertainty around mean cost difference and cost-effectiveness results. Bootstrapped cost-effect pairs were used to plot the cost-effectiveness (CE) plane and cost-effectiveness acceptability curve (CEAC).

FINDINGS: Diagnosis and treatment of early GDM was more effective and tended to be less costly, i.e., dominant (cost-saving) [-5.6% composite adverse pregnancy outcome (95% CI: -10.1%, -1.2%), -$1373 (95% CI: -$3,749, $642)] compared with usual care. Our findings were confirmed by both the CE plane (88% of the bootstrapped cost-effect pairs fall in the south-west quadrant), and CEAC (the probability of the intervention being cost-effective ranged from 84% at a willingness-to-pay (WTP) threshold value of $10,000-99% at a WTP threshold value of $100,000 per composite adverse pregnancy outcome prevented). Sub-group analyses demonstrated that diagnosis and treatment of early GDM among women in the higher glycemic range (fasting blood glucose 95-109 mg/dl [5.3-6.0 mmol/L], 1-h blood glucose ≥191 mg/dl [10.6 mmol/L] and/or 2-h blood glucose 162-199 mg/dl [9.0-11.0 mmol/L]) was more effective and less costly (dominant) [-7.8% composite adverse pregnancy outcome (95% CI: -14.6%, -0.9%), -$2795 (95% CI: -$6,638, -$533)]; the intervention was more effective and tended to be less costly [-8.9% composite adverse pregnancy outcome (95% CI: -15.1%, -2.6%), -$5548 (95% CI: -$16,740, $1547)] among women diagnosed before 14 weeks' gestation as well.

INTERPRETATION: Our findings highlight the potential health and economic benefits from the diagnosis and treatment of early GDM among women with risk factors for hyperglycemia in pregnancy and supports its implementation. Long-term follow-up studies are recommended as a key future area of research to assess the potential long-term health benefits and economic consequences of the intervention.

OBJECTIVE: To identify factors associated with neonatal respiratory distress (NRD) in early Gestational diabetes mellitus (eGDM).

DESIGN: Nested case-control analysis of the TOBOGM trial.

SETTING: Seventeen hospitals: Australia, Sweden, Austria and India. POPULATION: Pregnant women, <20 weeks' gestation, singleton, GDM risk factors.

METHODS: Women with GDM risk factors completed an oral glucose tolerance test (OGTT) before 20 weeks: those with eGDM (WHO-2013 criteria) were randomised to immediate or deferred GDM treatment. Logistic regression compared pregnancies with/without NRD, and in pregnancies with NRD, those with/without high-dependency nursery admission for ≤24 h with those admitted for >24 h. Comparisons were adjusted for age, pre-pregnancy body mass index, ethnicity, smoking, primigravity, education and site. Adjusted odds ratios (95% CI) are reported.

MAIN OUTCOME MEASURES: NRD definition: ≥4 h of respiratory support (supplemental oxygen or supported ventilation) postpartum. Respiratory distress syndrome (RDS): Supported ventilation and ≥24 h nursery stay.

RESULTS: Ninety-nine (12.5%) of 793 infants had NRD; incidence halved (0.50, 0.31-0.79) if GDM treatment was started early. NRD was associated with Caesarean section (2.31, 1.42-3.76), large for gestational age (LGA) (1.83, 1.09-3.08) and shorter gestation (0.95, 0.93-0.97 per day longer). Among NRD infants, >24 h nursery-stay was associated with higher OGTT 1-h glucose (1.38, 1.08-1.76 per mmol/L). Fifteen (2.0%) infants had RDS.

CONCLUSIONS: Identifying and treating eGDM reduces NRD risk. NRD is more likely with Caesarean section, LGA and shorter gestation. Further studies are needed to understand the mechanisms behind this eGDM complication and any long-term effects.

Gestational diabetes is defined as hyperglycaemia first detected during pregnancy at glucose concentrations that are less than those of overt diabetes. Around 14% of pregnancies globally are affected by gestational diabetes; its prevalence varies with differences in risk factors and approaches to screening and diagnosis; and it is increasing in parallel with obesity and type 2 diabetes. Gestational diabetes direct costs are US$1·6 billion in the USA alone, largely due to complications including hypertensive disorders, preterm delivery, and neonatal metabolic and respiratory consequences. Between 30% and 70% of gestational diabetes is diagnosed in early pregnancy (ie, early gestational diabetes defined by hyperglycaemia before 20 weeks of gestation). Early gestational diabetes is associated with worse pregnancy outcomes compared with women diagnosed with late gestational diabetes (hyperglycaemia from 24 weeks to 28 weeks of gestation). Randomised controlled trials show benefits of treating gestational diabetes from 24 weeks to 28 weeks of gestation. The WHO 2013 recommendations for diagnosing gestational diabetes (one-step 75 gm 2-h oral glucose tolerance test at 24-28 weeks of gestation) are largely based on the Hyperglycemia and Adverse Pregnancy Outcomes Study, which confirmed the linear association between pregnancy complications and late-pregnancy maternal glycaemia: a phenomenon that has now also been shown in early pregnancy. Recently, the Treatment of Booking Gestational Diabetes Mellitus (TOBOGM) trial showed benefit in diagnosis and treatment of early gestational diabetes for women with risk factors. Given the diabesity epidemic, evidence for gestational diabetes heterogeneity by timing and subtype, and advances in technology, a life course precision medicine approach is urgently needed, using evidence-based prevention, diagnostic, and treatment strategies.

OBJECTIVE: To compare the prevalence and clinical characteristics of early gestational diabetes (eGDM) and associated birth outcomes amongst women of different ethnic groups.

RESEARCH DESIGN AND METHODS: This is a secondary analysis of an international, multicentre randomized controlled trial of treating eGDM among pregnant women with GDM risk factors enrolled <20 weeks' gestation. The diagnosis of GDM was made using WHO-2013 criteria. While Europids required at least one risk factor for recruitment, for others, ethnicity itself was a risk factor.

RESULTS: Among women of Europid (n=1,567), South Asian (SA: n=971), East and South-East Asian (ESEA: n=498), Middle Eastern (ME: n=242) and Māori and Pasifika (MP: n=174) ethnicities; MP (26.4%) had the highest eGDM crude prevalence compared with Europid (20.3%), SA (24.7%), ESEA (22.3%) and ME (21.1%) (p<0.001). Compared with Europid, the highest eGDM adjusted odds ratio (aOR) was seen in SA (2.43 [95%CI 1.9-3.11]) and ESEA (aOR 2.28 [95%CI 1.68-3.08]); in late GDM, SA had the highest prevalence (20.4%: aOR 2.16 [95%CI 1.61-2.9]). Glucose patterns varied between ethnic groups and ESEA were predominantly diagnosed with eGDM through post-glucose load values, while all other ethnic groups were mainly diagnosed on fasting glucose values. There were no differences in the eGDM composite primary outcome or neonatal and pregnancy-related hypertension outcomes between the ethnic groups.

CONCLUSIONS: In women with risk factors, eGDM was most prevalent in SA and ESEA women, particularly identified by the post-glucose load samples. These findings suggest an early OGTT should particularly be performed in women from these ethnic groups.