Patterns of glycemia in normal pregnancy: should the current therapeutic targets be challenged?

Premeal Whey Protein Lowers Postprandial Blood Glucose in Women With Gestational Diabetes Mellitus: A Randomized, Crossover Clinical Trial

OBJECTIVE

To examine how whey protein served as a premeal affects postprandial glucose excursions in women with gestational diabetes mellitus (GDM).

RESEARCH DESIGN AND METHODS

A placebo-controlled, single-blinded, crossover, randomized trial including women with and without GDM (20-36 weeks' gestation) was performed. Participants were studied in the laboratory and at home. In the laboratory, women were randomized to consume 20 g of whey or placebo 30 min before undergoing, 7-14 days later, a 75-g oral glucose tolerance test (OGTT). Blood was sampled consecutively 3 hours following the OGTT. The primary end point was the incremental area under the curve (iAUC) for glucose. At home, participants wore continuous glucose monitors and, on subsequent days, randomly consumed 0, 10, 15, 20, and 30 g of whey 30 min before breakfast.

RESULTS

Twelve women with GDM and 12 pregnant women with normal glucose tolerance (NGT) to part in the trials. Intake of premeal whey resulted in lowered peak glucose by -1.0 mmol/L (95% CI -1.6 to -0.4) in women with GDM and -0.7 mmol/L (95% CI -1.3 to -0.1) in women without GDM compared with placebo. Insulin, glucose-dependent insulinotropic polypeptide, and glucagon-like peptide-1 levels increased rapidly after whey consumption in both groups. At home, a premeal of 30 g of whey dose-dependently reduced incremental glucose peaks with a maximum of -2.0 mmol/L (95% CI -2.5 to -1.5) in women with GDM compared with placebo.

CONCLUSIONS

Premeal whey consumption acutely lowers postprandial blood glucose in women with GDM and those with NGT, with 15-30 g lowering the glucose iAUC of women with GDM. These findings emphasize the need for long-term studies to assess the impact of whey premeals in pregnancies affected by GDM.

American Diabetes Association Professional Practice Committee, ElSayed NA, McCoy RG, Aleppo G, Balapattabi K, Beverly EA, Briggs Early K, Bruemmer D, Echouffo-Tcheugui JB, Ekhlaspour L, Garg R, Khunti K, Lal R, Lingvay I, Matfin G, Pandya N, Pekas EJ, Pilla SJ, Polsky S, Segal AR, Seley JJ, Stanton RC, Bannuru RR. 15. Management of Diabetes in Pregnancy: Standards of Care in Diabetes-2025

The American Diabetes Association (ADA) "Standards of Care in Diabetes" includes the ADA's current clinical practice recommendations and is intended to provide the components of diabetes care, general treatment goals and guidelines, and tools to evaluate quality of care. Members of the ADA Professional Practice Committee, an interprofessional expert committee, are responsible for updating the Standards of Care annually, or more frequently as warranted. For a detailed description of ADA standards, statements, and reports, as well as the evidence-grading system for ADA's clinical practice recommendations and a full list of Professional Practice Committee members, please refer to Introduction and Methodology. Readers who wish to comment on the Standards of Care are invited to do so at professional.diabetes.org/SOC.

A framework to classify gestational diabetes diagnosed by routine antenatal 75g glucose tolerance testing

OBJECTIVE

To create an objective framework to classify gestational diabetes mellitus diagnosed by routine antenatal 75 g diabetes testing results to provide an alternative to current treatment-based classification.

METHODS

A framework was created to classify gestational diabetes according to the severity of glycemic abnormalities after routine antenatal 75 g GTT (classes 1 through 4, determined by fasting and post-test glycemic abnormalities). A retrospective cohort chart review was used to correlate clinically how often diet therapy alone maintained glycemic targets throughout pregnancy in each class. Chi-square analysis was used to assess inter-class differences in the success of diet therapy alone maintaining glycemic targets throughout pregnancy.

RESULTS

Seventy-four of 228 (33%), 35/228 (15%), 76/228 (33%), and 43/228 (19%) of the study population were classified as Class 1, 2, 3, or 4, respectively. Of eighty-nine patients who maintained glycemic targets throughout pregnancy with diet alone 51/89 (57%) were Class 1, 20/89 (22.5%) were Class 2, 11/89 (12.5%) were Class 3, and 7/89 (8%) were Class 4. Chi-square analysis showed statistically significant inter-class differences in the likelihood of diet therapy alone maintaining glycemic targets throughout pregnancy.

CONCLUSION

In this framework classifying gestational diabetes according to the severity of glycemic abnormalities after routine antenatal 75 g GTT (an objective proxy for disease severity), the higher the assigned class, the less likely that diet therapy alone maintained glycemic targets throughout pregnancy (a clinical proxy for disease severity).

Insulin Management for Gestational and Type 2 Diabetes in Pregnancy

Insulin is preferred as the first-line agent for glucose management of gestational diabetes mellitus and type 2 diabetes in pregnancy when nutritional and lifestyle modifications are unable to achieve pregnancy-specific glucose targets. Individual heterogeneity in defects of insulin secretion or sensitivity in liver and muscle, unique genetic influences on pregnancy glycemic regulation, and variable cultural and lifestyle behaviors that affect meal, activity, sleep, and occupational schedules necessitate a personalized approach to insulin regimens. Newer insulin preparations have been developed to mimic the physiologic release of endogenous insulin, maintaining appropriate basal levels to cover hepatic gluconeogenesis and simulate the rapid, meal-related, bolus rise of insulin. Such physiologic basal-bolus dosing of insulin can be administered safely, achieving tighter glycemic control while reducing episodes of hypoglycemia. Insulin initiation and titration require understanding the pharmacodynamics of different insulin preparations in addition to a patient's glycemic profiles, effect of variable nutritional intake and mealtimes, physical activity, stress, timing of sleep cycles, and cultural habits. Educating and empowering patients to learn how their glucose responds to insulin, portion and content of meals, and physical activity can increase personal engagement in therapy, flexibility in eating patterns, and improved glycemic control. This Clinical Expert Series article is focused on optimizing insulin management (initiation, dosing, and titration) of gestational and type 2 diabetes in pregnancy.

Continuous Glucose Monitor Metrics That Predict Neonatal Adiposity in Early and Later Pregnancy Are Higher in Obesity Despite Macronutrient-Controlled Eucaloric Diets

BACKGROUND

Fasting glucose is higher in pregnancies with obesity (OB); less is known about postprandial (PP) and nocturnal patterns when the diet is eucaloric and fixed or about the continuous-glucose-monitor (CGM) metrics that predict neonatal adiposity (NB%fat). We hypothesized that continuous glucose monitors (CGMs) would reveal higher glycemia in OB vs. normal weight (NW) during Early (14-16 weeks) and Later (26-28 weeks) gestation despite macronutrient-controlled eucaloric diets and elucidate unique predictors of NB%fat.

METHODS

In a prospective, parallel-group comparative study, a eucaloric diet (NW: 25 kcal/kg; OB: 30 kcal/kg) was provided (50% carbohydrate [20% simple/30% complex; of total calories], 35% fat, 15% protein) to Early and Later gestation groups wearing a blinded CGM for three days. CGM metrics (mean fasting; 1 h and 2 h PP; daytime and nocturnal glucose; percent time-in-range (%TIR: 63-140 mg/dL); PP excursions; and area-under-the-curve [AUC]) were interrogated between groups and as predictors of NB%fat by dual X-ray absorptiometry(DXA).

RESULTS

Fifty-four women with NW (BMI: 23 kg/m2; n = 27) and OB (BMI: 32; n = 27) provided their informed consent to participate. Early, the daytime glucose was higher in OB vs. NW (mean ± SEM) (91 ± 2 vs. 85 ± 2 mg/dL, p = 0.017), driven by 2 h PP glucose (95 ± 2 vs. 88 ± 2, p = 0.004). Later, those with OB exhibited higher nocturnal (89 ± 2 vs. 81 ± 2), daytime (95 ± 2 vs. 87 ± 2), 1 h (109 ± 3 vs. 98 ± 2), and 2 h PP (101 ± 3 vs. 92 ± 2) glucose (all p < 0.05) but no difference in %TIR (95-99%). Postprandial peak excursions for all meals were markedly blunted in both the Early (9-19 mg/dL) and Later (15-26 mg/dL). In OB, the Later group's 24 h AUC was correlated with NB%fat (r = 0.534, p = 0.02). Despite similar weight gain, infants of OB had higher birthweight (3528 ± 107 vs. 3258 ± 74 g, p = 0.037); differences in NB%fat did not reach statistical significance (11.0 vs. 8.9%; p > 0.05).

CONCLUSIONS

Despite macronutrient-controlled eucaloric diets, pregnancies with OB had higher glycemia Early and Later in gestation; the Later 24 h glucose AUC correlated with NB%fat. However, glycemic patterns were strikingly lower than current management targets.

From Standard of Care to Emerging Innovations: Navigating the Evolution of Pharmacological Treatment of Gestational Diabetes

The incidence of gestational diabetes mellitus (GDM) continues to increase in the United States and globally. While the first-line treatment of GDM remains diet and exercise, 30% of patients with GDM will require pharmacotherapy. However, many controversies remain over the specific glycemic threshold values at which pharmacotherapy should be started, how intensified the therapy should be, and whether oral agents are effective in GDM and remain safe for long-term offspring health. This review will summarize recently completed and ongoing trials focused on GDM pharmacotherapy, including those examining different glycemic thresholds to initiate therapy and treatment intensity. KEY POINTS: · The incidence of GDM continues to increase in the United States and globally.. · While the first-line treatment of GDM remains diet, 30% of patients require pharmacotherapy.. · Controversies remain over the specific glycemic threshold values at which pharmacotherapy is needed.. · Another controversy is how tightly to control GDM.. · Additional controversies are the safety of metformin and incretins in terms of offspring's long-term health..

Clinical Risk Factors and First Gestational 75 g OGTT May Predict Recurrent and New-Onset Gestational Diabetes in Multiparous Women

Background: Women who experience gestational diabetes mellitus (GDM) during their first pregnancy are at a high risk of developing GDM again in subsequent pregnancies. Even mothers with no previous history of GDM may develop the condition in a new pregnancy. Methods: In this retrospective cross-sectional observational study, 759 multiparous women tested for GDM in two successive pregnancies using the 75 g OGTT (IADPSG criteria) were enrolled. The OGTT was performed at 24-28 weeks' gestation or earlier if there was a history of GDM. Participants were categorized into four groups: women with normal glucose tolerance (NGT) in both pregnancies (n = 493), women with a first occurrence of GDM in their second pregnancy (n = 74), women with non-recurrent GDM in their second pregnancy (n = 92), and women with recurrent GDM in their second pregnancy (n = 100). Results: Intergroup comparisons revealed clinical predictors of GDM in the first pregnancy (family history of type 2 diabetes, PCOS, advanced maternal age, pregravid obesity) and in the second pregnancy (interpregnancy BMI gain), as well as predictors of recurrent GDM (pregravid obesity, PCOS). A positive correlation was observed between the OGTT glucose levels of consecutive pregnancies. Adjusted logistic regression indicated that a higher 1-h post-load glucose level (≥130 mg/dL) during the first pregnancy significantly increased the likelihood of new-onset GDM in the second pregnancy (OR: 2.496), whereas a higher 2-h post-load glucose level (≥153 mg/dL) at the first diagnostic OGTT increased the likelihood of recurrent GDM (OR: 2.214). Conclusions: Clinical risk factors and post-load glucose levels during the first gestational 75 g OGTT can help predict new-onset or recurrent GDM in multiparous women.

Correlation Between the First Trimester Two-Hour Postprandial Blood Glucose Greater Than 110 mg/dL for the Prediction of Gestational Diabetes Mellitus

AIM

To determine the correlation between first-trimester two-hour postprandial blood glucose (PPBG) > 110 mg/dL for predicting gestational diabetes mellitus (GDM).

METHODS

This prospective cohort study enrolled 200 women between 8 and 10 weeks of gestation from February 2022 to February 2024. All recruited pregnant women underwent testing for two-hour PPBS at 8-10 weeks and were followed up till delivery. GDM screening was done during 14-16, 24-28, and 32-34 weeks of gestation.

RESULTS

Amongst women having PPBS > 110 mg/dL, 95.9% developed GDM, while in the group with PPBS < 110 mg/dL, only 4% developed GDM. In the PPBS > 110 mg/dL group, a significantly higher number of women were in the older age group (p < 0.049), had a higher BMI (p < 0.001), a family history of diabetes (p < 0.001), and previous history of abortion (p < 0.001). Women with PPBS > 110 mg/dL had significantly higher rates of cesarean section (p < 0.01), preterm delivery (p < 0.001), and macrosomia (p < 0.001). A positive correlation (r = 0.677; p < 0.001) was observed between first trimester two-hour PPBS and cord blood glucose levels. Similarly, a positive correlation (r = 0.465; p < 0.001) was present between insulin levels measured during the first trimester with cord blood insulin. The area under the curve (AUC) for PPBS was 0.969 (p < 0.001) with 95% CI: 0.933-0.988. PPBS > 110 mg/dL has a sensitivity of 95.9%, specificity of 95.6%, positive predictive value (PPV) of 95.9%, negative predictive value (NPV) of 95.7%, and diagnostic accuracy of 95.77% to predict GDM.

CONCLUSION

PPBS > 110 mg/dL at two hours exhibits high levels of diagnostic accuracy for the prediction of GDM and is associated with adverse fetomaternal outcomes. PPBG is a superior, physiologic, and low-cost option compared to HbA1c for early prediction of GDM and can also be performed as a simple point-of-care test with a glucometer at home or in the periphery by healthcare workers (HCW) and in wellness centers.

Continuous Glucose Monitoring Profiles in Pregnancies With and Without Gestational Diabetes Mellitus

OBJECTIVE

To determine whether continuous glucose monitoring (CGM)-derived glycemic patterns can characterize pregnancies with gestational diabetes mellitus (GDM) as diagnosed by standard oral glucose tolerance test at 24-28 weeks' gestation compared with those without GDM.

RESEARCH DESIGN AND METHODS

The analysis includes 768 individuals enrolled from two sites prior to 17 weeks' gestation between June 2020 and December 2021 in a prospective observational study. Participants wore blinded Dexcom G6 CGMs throughout gestation. Main outcome of interest was a diagnosis of GDM by oral glucose tolerance test (OGTT). Glycemic levels in participants with GDM versus without GDM were characterized using CGM-measured glycemic metrics.

RESULTS

Participants with GDM (n = 58 [8%]) had higher mean glucose (109 ± 13 vs. 100 ± 8 mg/dL [6.0 ± 0.7 vs. 5.6 ± 0.4 mmol/L], P < 0.001), greater glucose SD (23 ± 4 vs. 19 ± 3 mg/dL [1.3 ± 0.2 vs. 1.1 ± 0.2 mmol/L], P < 0.001), less time in range 63-120 mg/dL (3.5-6.7 mmol/L) (70% ± 17% vs. 84% ± 8%, P < 0.001), greater percent time >120 mg/dL (>6.7 mmol/L) (median 23% vs. 12%, P < 0.001), and greater percent time >140 mg/dL (>7.8 mmol/L) (median 7.4% vs. 2.7%, P < 0.001) than those without GDM throughout gestation prior to OGTT. Median percent time >120 mg/dL (>6.7 mmol/L) and time >140 mg/dL (>7.8 mmol/L) were higher as early as 13-14 weeks of gestation (32% vs. 14%, P < 0.001, and 5.2% vs. 2.0%, P < 0.001, respectively) and persisted during the entire study period prior to OGTT.

CONCLUSIONS

Prior to OGTT at 24-34 weeks' gestation, pregnant individuals who develop GDM have higher CGM-measured glucose levels and more hyperglycemia compared with those who do not develop GDM.

Continuous Glucose Monitoring Metrics for Pregnancies Complicated by Diabetes: Critical Appraisal of Current Evidence

Ascertaining the utility of continuous glucose monitoring (CGM) in pregnancy complicated by diabetes is a rapidly evolving area, as the prevalence of type 1 diabetes (T1D), type 2 diabetes (T2D), and gestational diabetes mellitus (GDM) escalates. The seminal randomized controlled trial (RCT) evaluating CGM use added to standard care in pregnancy in T1D demonstrated significant improvements in maternal glycemia and neonatal health outcomes. Current clinical guidance recommends targets for percentage time in range (TIR), time above range (TAR), and time below range (TBR) during pregnancy complicated by T1D that are widely used in clinical practice. However, the superiority of CGM over blood glucose monitoring (BGM) is still questioned in both T2D and GDM, and whether glucose targets should be different than in T1D is unknown. Questions requiring additional research include which CGM metrics are superior in predicting clinical outcomes, how should pregnancy-specific CGM targets be defined, whether CGM targets should differ according to gestational age, and if CGM metrics during pregnancy should be similar across all types of diabetes. Limiting the potential for CGM to improve pregnancy outcomes may be our inability to maintain TIR > 70% throughout gestation, a goal achieved in the minority of patients studied. Adverse pregnancy outcomes remain high in women with T1D and T2D in pregnancy despite CGM technology, and this review explores the potential reasons and questions yet to be investigated.

Glucose levels measured with continuous glucose monitoring in uncomplicated pregnancies

INTRODUCTION

To characterize glucose levels during uncomplicated pregnancies, defined as pregnancy with a hemoglobin A1c <5.7% (<39 mmol/mol) in early pregnancy, and without a large-for-gestational-age birth, hypertensive disorders of pregnancy, or gestational diabetes mellitus (ie, abnormal oral glucose tolerance test).

RESEARCH DESIGN AND METHODS

Two sites enrolled 937 pregnant individuals aged 18 years and older prior to reaching 17 gestational weeks; 413 had an uncomplicated pregnancy (mean±SD body mass index (BMI) of 25.3±5.0 kg/m2) and wore Dexcom G6 continuous glucose monitoring (CGM) devices throughout the observed gestational period. Mealtimes were voluntarily recorded. Glycemic levels during gestation were characterized using CGM-measured glycemic metrics.

RESULTS

Participants wore CGM for a median of 123 days each. Glucose levels were nearly stable throughout all three trimesters in uncomplicated pregnancies. Overall mean±SD glucose during gestation was 98±7 mg/dL (5.4±0.4 mmol/L), median per cent time 63-120 mg/dL (3.5-6.7 mmol/L) was 86% (IQR: 82-89%), median per cent time <63 mg/dL (3.5 mmol/L) was 1.8%, median per cent time >120 mg/dL (6.7 mmol/L) was 11%, and median per cent time >140 mg/dL (7.8 mmol/L) was 2.5%. Mean post-prandial peak glucose was 126±22 mg/dL (7.0±1.2 mmol/L), and mean post-prandial glycemic excursion was 36±22 mg/dL (2.0±1.2 mmol/L). Higher mean glucose levels were low to moderately associated with pregnant individuals with higher BMIs (103±6 mg/dL (5.7±0.3 mmol/L) for BMI ≥30.0 kg/m2 vs 96±7 mg/dL (5.3±0.4 mmol/L) for BMI 18.5-<25 kg/m2, r=0.35).

CONCLUSIONS

Mean glucose levels and time 63-120 mg/dL (3.5-6.7 mmol/L) remained nearly stable throughout pregnancy and values above 140 mg/dL (7.8 mmol/L) were rare. Mean glucose levels in pregnancy trend higher as BMI increases into the overweight/obesity range. The glycemic metrics reported during uncomplicated pregnancies represent treatment targets for pregnant individuals.

Intensive glycaemic targets in overweight and obese individuals with gestational diabetes mellitus: clinical trial protocol for the iGDM study

INTRODUCTION

The prevalence of both obesity and gestational diabetes mellitus (GDM) has increased, and each is associated with adverse perinatal outcomes including fetal overgrowth, neonatal morbidity, hypertensive disorders of pregnancy and caesarean delivery. Women with GDM who are also overweight or obese have higher rates of pregnancy complications when compared with normal-weight women with GDM, which may occur in part due to suboptimal glycaemic control. The current recommendations for glycaemic targets in pregnant women with diabetes are based on limited evidence and exceed the mean fasting (70.9±7.8 mg/dL) and 1-hour postprandial (108.9±12.9 mg/dL) glucose values in pregnant individuals without diabetes. Our prior work demonstrated that the use of intensive (fasting <90 mg/dL and 1-hour postprandial <120 mg/dL) compared with standard (fasting <95 mg/dL and 1-hour postprandial <140 mg/dL) glycaemic targets resulted in improved glycaemic control without increasing the risk for hypoglycaemia in pregnant individuals with GDM, but the impact of intensive glycaemic targets on perinatal outcomes is unknown.

METHODS AND ANALYSIS

The Intensive Glycemic Targets in Overweight and Obese Women with Gestational Diabetes Mellitus: A Multicenter Randomized Trial (iGDM Trial) is a large, pragmatic randomised clinical trial designed to investigate the impact of intensive versus standard glycaemic targets on perinatal outcomes in women with GDM who are overweight and obese. During the 5-year project period, a multidisciplinary team of investigators from five medical centres representing regions of the USA with high rates of obesity will randomise 828 overweight and obese women with GDM to either intensive or standard glycaemic targets. We will test the central hypothesis that intensive glycaemic targets will result in lower rates of neonatal composite morbidity including large for gestational age birth weight, neonatal hypoglycaemia, respiratory distress syndrome and need for phototherapy when compared with standard glycaemic targets using the intention-to-treat approach to analysis.

ETHICS AND DISSEMINATION

The Institutional Review Board (IRB) at Indiana University School of Medicine approved this study (IRB# 11435; initial approval date 25 August 2021). We will submit the results of the trial for publication in peer-reviewed journals and presentations at international scientific meetings.

TRIAL REGISTRATION NUMBER

NCT05124808.

American Diabetes Association Professional Practice Committee, ElSayed NA, Aleppo G, Bannuru RR, Bruemmer D, Collins BS, Ekhlaspour L, Hilliard ME, Johnson EL, Khunti K, Lingvay I, Matfin G, McCoy RG, Perry ML, Pilla SJ, Polsky S, Prahalad P, Pratley RE, Segal AR, Seley JJ, Stanton RC, Gabbay RA. 15. Management of Diabetes in Pregnancy: Standards of Care in Diabetes-2024

The American Diabetes Association (ADA) "Standards of Care in Diabetes" includes the ADA's current clinical practice recommendations and is intended to provide the components of diabetes care, general treatment goals and guidelines, and tools to evaluate quality of care. Members of the ADA Professional Practice Committee, an interprofessional expert committee, are responsible for updating the Standards of Care annually, or more frequently as warranted. For a detailed description of ADA standards, statements, and reports, as well as the evidence-grading system for ADA's clinical practice recommendations and a full list of Professional Practice Committee members, please refer to Introduction and Methodology. Readers who wish to comment on the Standards of Care are invited to do so at professional.diabetes.org/SOC.

Flash glucose monitoring system in gestational diabetes: a study of accuracy and usability

PURPOSE

Studies of flash glucose monitoring systems (FGMSs) in pregnancy are insufficient, especially in gestational diabetes (GD). Our aim was to evaluate Freestyle Libre's usability and accuracy (compared to self-monitoring of blood glucose [SMBG]) for GD patients in real-life conditions.

METHODS

This is a prospective study with pregnant women diagnosed with GD (n = 24 for the usability analysis; n = 19 for the accuracy analysis). The study duration was up to 28 days (lifetime of two sensors). Participants executed a minimum of four daily FGMS readings obtained immediately after capillary SMBG. Analytical accuracy was assessed with mean absolute relative difference (MARD) and mean absolute difference (MAD); clinical accuracy was assessed with Surveillance Error Grid (SEG). Usability was evaluated with a user acceptability questionnaire.

RESULTS

The mean pregestational BMI was 25.21 ± 5.15 kg/m2 (mean ± SD), the mean gestational age was 30.31 ± 2.02 weeks, and the mean glucose values were 76.63 ± 7.49 mg/dL. A total of 1339 SMBG-FGMS pairs of values were obtained. Analytical accuracy was good with an overall MARD of 14.07% and an in-target MARD of 13.79%. The number of SMBG-FMGS pairs for above-target values was low (122 of 1339) with an associated MARD of 17.95%. Clinical accuracy of the FGMS was demonstrated, with 94.4% of values in the no-risk or slight, lower risk zones of the SEG. FGMS accuracy was unaffected by pregestational BMI or gestational age. The user acceptability questionnaire showed high levels of satisfaction, with 95.8-100% preferring FGMS to SMBG. No unexpected or severe adverse effects occurred.

CONCLUSION

FGMS showed good performance in GD regarding accuracy and usability. Larger studies are needed to corroborate our results, verify the analytical accuracy of above-target values as this glucose range might lead to initiation or adjustment of pharmacological therapy, and ultimately establish definitive recommendations regarding prescription of FGMS for GD patients.

Roadmap to the Effective Use of Continuous Glucose Monitoring in Pregnancy

The landscape for managing type 1 diabetes during pregnancy has been transformed by increasing use of continuous glucose monitoring (CGM). Women are aiming for pregnancy-specific glucose targets or 70% time in range for pregnancy (TIRp; 63-140 mg/dL) as soon as possible, knowing that every extra 5% TIRp has benefits for reducing the risks of complications in their babies. Ongoing monitoring of maternal A1C (at pregnancy confirmation and at 20, 28, and 36 weeks' gestation) remains useful. Intensification of glycemic management and instruction in using CGM (if not already used) is recommended for individuals with an A1C >6.0% after 20 weeks. A better understanding of CGM-documented glycemic changes throughout pregnancy is needed to inform future management of gestational diabetes and pregnancy in people with type 2 diabetes. Research regarding overcoming barriers to CGM use and optimal TIRp targets for pregnant individuals with type 2 diabetes from diverse racial/ethnic groups is urgently needed.

Randomization to a Provided Higher-Complex-Carbohydrate Versus Conventional Diet in Gestational Diabetes Mellitus Results in Similar Newborn Adiposity

OBJECTIVE

Nutrition therapy for gestational diabetes mellitus (GDM) has conventionally focused on carbohydrate restriction. In a randomized controlled trial (RCT), we tested the hypothesis that a diet (all meals provided) with liberalized complex carbohydrate (60%) and lower fat (25%) (CHOICE diet) could improve maternal insulin resistance and 24-h glycemia, resulting in reduced newborn adiposity (NB%fat; powered outcome) versus a conventional lower-carbohydrate (40%) and higher-fat (45%) (LC/CONV) diet.

RESEARCH DESIGN AND METHODS

After diagnosis (at ∼28-30 weeks' gestation), 59 women with diet-controlled GDM (mean ± SEM; BMI 32 ± 1 kg/m2) were randomized to a provided LC/CONV or CHOICE diet (BMI-matched calories) through delivery. At 30-31 and 36-37 weeks of gestation, a 2-h, 75-g oral glucose tolerance test (OGTT) was performed and a continuous glucose monitor (CGM) was worn for 72 h. Cord blood samples were collected at delivery. NB%fat was measured by air displacement plethysmography (13.4 ± 0.4 days).

RESULTS

There were 23 women per group (LC/CONV [214 g/day carbohydrate] and CHOICE [316 g/day carbohydrate]). For LC/CONV and CHOICE, respectively (mean ± SEM), NB%fat (10.1 ± 1 vs. 10.5 ± 1), birth weight (3,303 ± 98 vs. 3,293 ± 81 g), and cord C-peptide levels were not different. Weight gain, physical activity, and gestational age at delivery were similar. At 36-37 weeks of gestation, CGM fasting (86 ± 3 vs. 90 ± 3 mg/dL), 1-h postprandial (119 ± 3 vs. 117 ± 3 mg/dL), 2-h postprandial (106 ± 3 vs. 108 ± 3 mg/dL), percent time in range (%TIR; 92 ± 1 vs. 91 ± 1), and 24-h glucose area under the curve values were similar between diets. The %time >120 mg/dL was statistically higher (8%) in CHOICE, as was the nocturnal glucose AUC; however, nocturnal %TIR (63-100 mg/dL) was not different. There were no between-group differences in OGTT glucose and insulin levels at 36-37 weeks of gestation.

CONCLUSIONS

A ∼100 g/day difference in carbohydrate intake did not result in between-group differences in NB%fat, cord C-peptide level, maternal 24-h glycemia, %TIR, or insulin resistance indices in diet-controlled GDM.

Different intensities of glycaemic control for women with gestational diabetes mellitus

BACKGROUND

Gestational diabetes mellitus (GDM) has major short- and long-term implications for both the mother and her baby. GDM is defined as a carbohydrate intolerance resulting in hyperglycaemia or any degree of glucose intolerance with onset or first recognition during pregnancy from 24 weeks' gestation onwards and which resolves following the birth of the baby. Rates for GDM can be as high as 25% depending on the population and diagnostic criteria used, and overall rates are increasing globally. There is wide variation internationally in glycaemic treatment target recommendations for women with GDM that are based on consensus rather than high-quality trials.

OBJECTIVES

To assess the effect of different intensities of glycaemic control in pregnant women with GDM on maternal and infant health outcomes.

SEARCH METHODS

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register, ClinicalTrials.gov, the World Health Organization International Clinical Trials Registry Platform (26 September 2022), and reference lists of the retrieved studies.

SELECTION CRITERIA

We included randomised controlled trials (RCTs), cluster-RCTs, and quasi-RCTs. Trials were eligible for inclusion if women were diagnosed with GDM during pregnancy and the trial compared tighter and less-tight glycaemic targets during management. We defined tighter glycaemic targets as lower numerical glycaemic concentrations, and less-tight glycaemic targets as higher numerical glycaemic concentrations.

DATA COLLECTION AND ANALYSIS

We used standard Cochrane methods for carrying out data collection, assessing risk of bias, and analysing results. Two review authors independently assessed trial eligibility for inclusion, evaluated risk of bias, and extracted data for the four included studies. We assessed the certainty of evidence for selected outcomes using the GRADE approach. Primary maternal outcomes included hypertensive disorders of pregnancy and subsequent development of type 2 diabetes. Primary infant outcomes included perinatal mortality, large-for-gestational-age, composite of mortality or serious morbidity, and neurosensory disability.

MAIN RESULTS

This was an update of a previous review completed in 2016. We included four RCTs (reporting on 1731 women) that compared a tighter glycaemic control with less-tight glycaemic control in women diagnosed with GDM. Three studies were parallel RCTs, and one study was a stepped-wedged cluster-RCT. The trials took place in Canada, New Zealand, Russia, and the USA. We judged the overall risk of bias to be unclear. Two trials were only published in abstract form. Tight glycaemic targets used in the trials ranged between ≤ 5.0 and 5.1 mmol/L for fasting plasma glucose and ≤ 6.7 and 7.4 mmol/L postprandial. Less-tight targets for glycaemic control used in the included trials ranged between < 5.3 and 5.8 mmol/L for fasting plasma glucose and < 7.8 and 8.0 mmol/L postprandial. For the maternal outcomes, compared with less-tight glycaemic control, the evidence suggests a possible increase in hypertensive disorders of pregnancy with tighter glycaemic control (risk ratio (RR) 1.16, 95% confidence interval (CI) 0.80 to 1.69, 2 trials, 1491 women; low certainty evidence); however, the 95% CI is compatible with a wide range of effects that encompass both benefit and harm. Tighter glycaemic control likely results in little to no difference in caesarean section rates (RR 0.98, 95% CI 0.82 to 1.17, 3 studies, 1662 women; moderate certainty evidence) or induction of labour rates (RR 0.96, 95% CI 0.78 to 1.18, 1 study, 1096 women; moderate certainty evidence) compared with less-tight control. No data were reported for the outcomes of subsequent development of type 2 diabetes, perineal trauma, return to pre-pregnancy weight, and postnatal depression. For the infant outcomes, it was difficult to determine if there was a difference in perinatal mortality (RR not estimable, 2 studies, 1499 infants; low certainty evidence), and there was likely no difference in being large-for-gestational-age (RR 0.96, 95% CI 0.72 to 1.29, 3 studies, 1556 infants; moderate certainty evidence). The evidence suggests a possible reduction in the composite of mortality or serious morbidity with tighter glycaemic control (RR 0.84, 95% CI 0.55 to 1.29, 3 trials, 1559 infants; low certainty evidence); however, the 95% CI is compatible with a wide range of effects that encompass both benefit and harm. There is probably little difference between groups in infant hypoglycaemia (RR 0.92, 95% CI 0.72 to 1.18, 3 studies, 1556 infants; moderate certainty evidence). Tighter glycaemic control may not reduce adiposity in infants of women with GDM compared with less-tight control (mean difference -0.62%, 95% CI -3.23 to 1.99, 1 study, 60 infants; low certainty evidence), but the wide CI suggests significant uncertainty. We found no data for the long-term outcomes of diabetes or neurosensory disability. Women assigned to tighter glycaemic control experienced an increase in the use of pharmacological therapy compared with women assigned to less-tight glycaemic control (RR 1.37, 95% CI 1.17 to 1.59, 4 trials, 1718 women). Tighter glycaemic control reducedadherence with treatment compared with less-tight glycaemic control (RR 0.41, 95% CI 0.32 to 0.51, 1 trial, 395 women). Overall the certainty of evidence assessed using GRADE ranged from low to moderate, downgraded primarily due to risk of bias and imprecision.

AUTHORS' CONCLUSIONS

This review is based on four trials (1731 women) with an overall unclear risk of bias. The trials provided data on most primary outcomes and suggest that tighter glycaemic control may increase the risk of hypertensive disorders of pregnancy. The risk of birth of a large-for-gestational-age infant and perinatal mortality may be similar between groups, and tighter glycaemic targets may result in a possible reduction in composite of death or severe infant morbidity. However, the CIs for these outcomes are wide, suggesting both benefit and harm. There remains limited evidence regarding the benefit of different glycaemic targets for women with GDM to minimise adverse effects on maternal and infant health. Glycaemic target recommendations from international professional organisations vary widely and are currently reliant on consensus given the lack of high-certainty evidence. Further high-quality trials are needed, and these should assess both short- and long-term health outcomes for women and their babies; include women's experiences; and assess health services costs in order to confirm the current findings. Two trials are ongoing.

MAGIC (maternal glucose in pregnancy) understanding the glycemic profile of pregnancy, intensive CGM glucose profiling and its relationship to fetal growth: an observational study protocol

BACKGROUND

Continuous glucose monitoring (CGM) provides the most objective method of assessing glucose in daily life. Although there have been small, short-term physiologic studies of glucose metabolism in 'healthy' pregnant women a comprehensive, longitudinal description of changes in glucose over the course of pregnancy and how glucose dysregulation earlier in pregnancy relates to traditional third trimester screening for gestational diabetes, fetal growth and pregnancy outcomes is lacking. This study aims to characterise longitudinal changes in glycemia across gestation using CGM, in order to understand the evolution of dysglycemia and its relationship to fetal growth.

METHOD/DESIGN

A multi-centre, prospective, observational, cohort study of 500 healthy pregnant women, recruited in the first trimester of pregnancy. Masked CGM will be performed for a 14-day period on five occasions across pregnancy at ~ 10-12, 18-20, 26-28, 34-36 weeks gestation and postnatally. Routinely collected anthropometric and sociodemographic information will be recorded at each visit including: weight, height, blood pressure, current medication. Age, parity, ethnicity, smoking will be recorded. Blood samples will be taken at each visit for HbA1c and a sample stored. Details on fetal growth from ultrasound scans and the OGTT results will be recorded. Maternal and neonatal outcomes will be collected. CGM glucose profiling is the exposure of interest, and will be performed using standard summary statistics, functional data analysis and glucotyping. The primary maternal outcome is clinical diagnosis of GDM. The primary neonatal outcome is large for gestational age (LGA) (> 90th centile defined by customised birthweight centile). The relationship of glucose to key secondary maternal and neonatal outcomes will be explored.

DISCUSSION

This study will ascertain the relationship of maternal dysglycemia to fetal growth and outcomes. It will explore whether CGM glucose profiling can detect GDM before the OGTT; or indeed whether CGM glucose profiling may be more useful than the OGTT at detecting LGA and other perinatal outcomes.

TRIAL REGISTRATION

ISRCTN 15,706,303 https://www.isrctn.com/ISRCTN15706303 Registration date: 13th March 2023.

Achievement of Target Glycemic Goal with Simple Basal Insulin Regimen in Women with Gestational Diabetes: A Prospective Cohort Study

There is little evidence concerning the need to treat gestational diabetes (GDM) in the same way as pregestational diabetes. We evaluated the efficacy of the simple insulin injection (SII) regimen for achieving the target glucose goal without increasing adverse perinatal outcomes in singleton pregnant women with GDM. All subjects underwent self-monitoring of blood glucose (SMBG), and insulin therapy was indicated according to the SMBG profile. Insulin was initially started with the SII regimen, in which one daily injection of NPH insulin before breakfast was used, and another NPH injection was added at bedtime, if necessary. We used the target glucose as <95 mg/dL at fasting and <120 mg/dL postprandial and accepted <130 mg/dL for the latter. If the target glucose did not reach with the regimen, we switched to the multiple daily injection (MDI) with additional prandial insulin aspart. We compared the SMBG profile before delivery as well as the perinatal outcomes between the SII and MDI groups. Among 361 women (age 33.7 years, nullipara 41%, prepregnancy body mass index 23.2 kg/m²) with GDM, 59%, 18%, and 23% were in the diet-alone, SII, and MDI groups, respectively. Consequently, regarding women requiring insulin therapy, 43% were treated with the SII regimen throughout pregnancy. The severity of baseline hyperglycemia according to the SMBG data at baseline was the MDI>the SII>the diet group. The rate of achieving target glucose levels before delivery in the SII group at fasting, postprandial < 120 mg/dL and <130 mg/dL were 93%, 54% and 87%, respectively, which were similar to that in the MDI group (93%, 57%, and 93%, respectively), with no significant differences in perinatal outcomes. In conclusion, more than 40% of women with GDM requiring insulin therapy achieved the target glucose goal with this simple insulin regimen without any increase in adverse effects.

Re-examination of the estimated average requirement for carbohydrate intake during pregnancy: Addition of placental glucose consumption

Evidence-based dietary reference intakes for nutrients in healthy individuals were last set in 2005 by the Institute of Medicine. For the first time, these recommendations included a guideline for carbohydrate intake during pregnancy. The recommended dietary allowance (RDA) was set at ≥175 g/d or 45%-65% of total energy intake. In the decades since, carbohydrate intake has been declining in some populations, and many pregnant women consume carbohydrates below the RDA. The RDA was developed to account for both maternal brain and fetal brain glucose requirements. However, the placenta also requires glucose as its dominant energy substrate and is as dependent on maternal glucose as the brain. Prompted by the availability of evidence demonstrating the rate and quantity of human placental glucose consumption, we calculated a potential new estimated average requirement (EAR) for carbohydrate intake to account for placental glucose consumption. Further, by narrative review, we have re-examined the original RDA by applying contemporary measurements of adult brain and whole-body fetal glucose consumption. We also propose, using physiologic rationale, that placental glucose consumption be included in pregnancy nutrition considerations. Calculated from human in vivo placental glucose consumption data, we suggest that 36 g/d represents an EAR for adequate glucose to support placental metabolism without supplementation by other fuels. A potential new EAR of 171 g/d accounts for maternal (100 g) and fetal (35 g) brain, and now placental glucose utilization (36 g), and with extrapolation to meet the needs of nearly all healthy pregnant women, would result in a modified RDA of 220 g/d. Lower and upper safety thresholds for carbohydrate intake remain to be determined, of importance as preexisting and gestational diabetes continue to rise globally, and nutrition therapy remains the cornerstone of treatment.

15. Management of Diabetes in Pregnancy: Standards of Care in Diabetes-2023

The American Diabetes Association (ADA) "Standards of Care in Diabetes" includes the ADA's current clinical practice recommendations and is intended to provide the components of diabetes care, general treatment goals and guidelines, and tools to evaluate quality of care. Members of the ADA Professional Practice Committee, a multidisciplinary expert committee, are responsible for updating the Standards of Care annually, or more frequently as warranted. For a detailed description of ADA standards, statements, and reports, as well as the evidence-grading system for ADA's clinical practice recommendations and a full list of Professional Practice Committee members, please refer to Introduction and Methodology. Readers who wish to comment on the Standards of Care are invited to do so at professional.diabetes.org/SOC.

Association of ambient fine particulate matter exposure with gestational diabetes mellitus and blood glucose levels during pregnancy

BACKGROUND

Previous studies have examined the associations between ambient fine particulate matter (PM_2.5) exposure and gestational diabetes mellitus (GDM). However, limited studies explored the relationships between PM_2.5 exposure and blood glucose levels during pregnancy, especially in highly polluted areas.

OBJECTIVES

To examine the associations of prenatal ambient PM_2.5 exposure with GDM and blood glucose levels, and to identify the sensitive exposure windows in a highly air-polluted area.

METHODS

From July 2016 to October 2017, a birth cohort study was conducted in Beijing, China. Participants were interviewed in each trimester regarding demographics, lifestyle, living and working environment, and medical conditions. Participant's daily ambient PM_2.5 levels from 3 m before last menstrual period (LMP) to the third trimester was estimated by a hybrid spatiotemporal model. Indoor air quality index was calculated based on environmental tobacco smoke, ventilation, cooking, painting, pesticide, and herbicide use. Distributed lag non-linear model was applied to explore the sensitive weeks of PM_2.5 exposure.

RESULTS

Of 165 pregnant women, 23 (13.94%) developed GDM. After adjusting for potential confounders, PM_2.5 exposure during the 1^st trimester was associated with higher odds of GDM (10 μg/m³ increase: OR = 1.89, 95% CI: 1.04-3.49). Each 10 μg/m³ increase in PM_2.5 during the 2^nd trimester was associated with 17.70% (2.21-33.20), 15.99% (2.96-29.01), 18.82% (4.11-33.52), and 17.10% (3.28-30.92) increase in 1-h, 2-h, Δ1h-fasting (1-h minus fasting), and Δ2h-fasting (2-h minus fasting) blood glucose levels, respectively. PM_2.5 exposure at 24^th-27^th weeks after LMP was associated with increased GDM risk. We identified sensitive exposure windows of 21^st-24^th weeks for higher 1-h and 2-h blood glucose levels and of 20^th-22^nd weeks for increased Δ1h-fasting and Δ2h-fasting.

CONCLUSIONS

Ambient PM_2.5 exposure during the second trimester was associated with higher odds of GDM and higher blood glucose levels. Avoiding exposure to high air pollution levels during the sensitive windows might prevent women from developing GDM.

A Clinical Update on Gestational Diabetes Mellitus

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.

Perceptions of Key Informant Health Professionals before implementing tighter glycaemic targets for women with gestational diabetes mellitus in New Zealand

Background

Tighter glycaemic targets may be of benefit for women with GDM and their infants. Barrier and enabler identification prior to implementation of tighter glycaemic targets for women with GDM may support a successful transition.

Methods

A cross-sectional questionnaire survey was conducted among Key Informant Health Professionals in ten hospitals in New Zealand. The survey assessed what was currently working using less tight glycaemic targets; what barriers and enablers were considered likely when introducing tighter glycaemic targets and whether these perceptions differed by health professional groups.

Results

Sixty Key Health Informant Health Professionals completed the survey. When using the lower glycaemic targets, participants considered that women with GDM found the targets easy to use and that collaborative collegial support was effective. No significant barriers were identified. Perceived enablers identified prior to implementation of tighter targets included receiving collegial support (40, 67%), attending education sessions (38, 63%), use of pocket prompt cards (31, 52%), availability of wall charts (25, 42%) and glycaemic target reminder stickers (24, 40%). For health professionals referring into the Diabetes in Pregnancy Service effective communication (50, 83%) was considered important. Perceived barriers were confusion over glycaemic targets use (27 (45%), not being informed of the glycaemic target change (31, 52%), non-involvement with multidisciplinary decisions (29, 48%) and increased difficulty of blood glucose control for women (48, 80%). Overall, barriers and enablers between Health Professional groups did not differ.

Discussion

Key Informant Health Professionals reported effective communication as a key perceived enabler and that woman would find it more difficult to control their blood glucose concentrations. Education sessions, multidisciplinary engagement, wall charts and stickers were considered effective to overcome the perceived barriers. Further research is needed to assess if the barriers perceived were realised and if the perceived enablers supported the implementation of the tighter glycaemic targets effectively.

Hyperinsulinaemia in pregnancy and gestational outcomes: A case series

Background: Pathological insulin resistance in pregnancy is associated with an increased risk for complications such as gestational diabetes mellitus and pre-eclampsia. Individuals with pathological insulin resistance also exhibit hyperinsulinaemia. Currently, there are no diagnostic criteria for pathological hyperinsulinaemia in pregnancy that may be used to indicate risk of adverse outcomes.Aim: This case series aimed to explore the relationship between first trimester insulin response patterns and gestational outcomes.Setting: Auckland, New Zealand.Methods: Participants included four pregnant women with prepregnancy body mass index ≥ 25 kg/m2 and aged 25–35 years. Glucose and insulin response patterns were examined following a 120 min oral glucose tolerance test (OGTT) at 12–15 weeks of gestation using a modified Kraft methodology. Outcomes assessed at 25 and 35 weeks of gestation included gestational weight gain (GWG), blood pressure, fasting capillary blood glucose and foetal growth. Lifestyle and medical information were collected at each trimester. After delivery, total GWG, infant size, delivery method and clinical outcomes were recorded.Results: Kraft pattern IIB hyperinsulinaemia was identified in two cases. Amongst them, Case #1 experienced excessive GWG, induction of labour and surgically assisted delivery. Case #4 delivered by emergency caesarean, and the neonate required intensive care admission for 17 h. No cases developed hyperglycaemia or hypertension. Infant weights were between 3.75 kg and 3.86 kg.Conclusion: Dynamic insulin assay provides a promising template to assess metabolic risk in the first trimester of pregnancy. Diagnosing hyperinsulinaemia early in pregnancy means that lifestyle-based initiatives could be introduced earlier to mitigate excess GWG and potential adverse outcomes.

Determinants of Small for Gestational Age in Women With Type 2 Diabetes in Pregnancy: Who Should Receive Metformin?

OBJECTIVE

In the MiTy (Metformin in Women With Type 2 Diabetes in Pregnancy) randomized trial of metformin versus placebo added to insulin, we found numerous benefits with metformin but identified an increased proportion of infants who were small for gestational age (SGA). We aimed to determine the predictors of SGA in order to individualize care.

RESEARCH DESIGN AND METHODS

Using logistic regression, we assessed baseline maternal characteristics as predictors of SGA. We compared maternal/neonatal outcomes in SGA metformin and placebo groups using the t, χ2, or Fisher exact test, as appropriate.

RESULTS

Among the 502 mothers, 460 infants were eligible for this study. There were 30 infants with SGA in the metformin group (12.9%) and 15 in the placebo group (6.6%) (P = 0.026). Among SGA infants, those in the metformin group were delivered significantly later than those in the placebo group (37.2 vs. 35.3 weeks; P = 0.038). In adjusted analyses, presence of a comorbidity (chronic hypertension and/or nephropathy) (odds ratio [OR] 3.05; 95% CI 1.58-5.81) and metformin use (OR 2.26; 95% CI 1.19-4.74) were predictive of SGA. The absolute risk of SGA was much higher in women receiving metformin with comorbidity compared with women receiving metformin without comorbidity (25.0% vs. 9.8%).

CONCLUSIONS

In this study, we observed a high percentage of SGA births among women with type 2 diabetes and chronic hypertension and/or nephropathy who were treated with metformin. Therefore, with the aim of reducing SGA, it is reasonable to be cautious in our use of metformin in those with type 2 diabetes and chronic hypertension or nephropathy in pregnancy.

Residual risk associations between initial hyperglycemia and adverse pregnancy outcomes in a large cohort including 6709 women with gestational diabetes

AIMS

. - To estimate the residual risk associations between hyperglycemia and adverse pregnancy outcomes after glycemia-controlling intervention.

METHODS

. - Among 41,067 Chinese women, those with gestational diabetes mellitus (GDM), according to the IADPSG criteria, received standard interventions to control glycemia. Risk associations of plasma glucose (PG) levels with excess newborn birth weight, primary cesarean section, and preterm delivery were estimated and compared with those in the Hyperglycemia and Adverse Pregnancy Outcomes (HAPO) study, where hyperglycemia was left untreated.

RESULTS

. - A total of 6,709 (16.3%) women developed GDM and thus received predominantly lifestyle interventions. The incidence of excess newborn birth weight, primary cesarean section, and preterm delivery was 6.1%, 19.1%, and 4.0%, respectively. Higher fasting and higher post-load PG levels during 75-g oral glucose tolerance test (OGTT) were statistically significantly associated with increased risks of excess newborn birth weight and pre-term delivery. Compared with the HAPO study, the association of fasting PG level with excess newborn birth weight showed similar strength and dose-response pattern, contrasting with considerably weakened associations for post-load PG levels that involved glycemic control. Contrary risk associations were seen across GDM subtypes compared with non-GDM, isolated fasting GDM was associated with increased, whereas isolated post-load GDM was associated with decreased, risks of excess newborn birth weight and primary cesarean section. Limiting the analysis to non-GDM women and GDM women with low HbA1c (<6.0%) ≥30 days after interventions overall attenuated the risk associations.

CONCLUSIONS

. - Residual risk associations exist between hyperglycemia and adverse pregnancy outcomes despite seemingly appropriate glycemic control.

American Diabetes Association Professional Practice Committee. 15. Management of Diabetes in Pregnancy: Standards of Medical Care in Diabetes-2022

The American Diabetes Association (ADA) "Standards of Medical Care in Diabetes" includes the ADA's current clinical practice recommendations and is intended to provide the components of diabetes care, general treatment goals and guidelines, and tools to evaluate quality of care. Members of the ADA Professional Practice Committee, a multidisciplinary expert committee (https://doi.org/10.2337/dc22-SPPC), are responsible for updating the Standards of Care annually, or more frequently as warranted. For a detailed description of ADA standards, statements, and reports, as well as the evidence-grading system for ADA's clinical practice recommendations, please refer to the Standards of Care Introduction (https://doi.org/10.2337/dc22-SINT). Readers who wish to comment on the Standards of Care are invited to do so at professional.diabetes.org/SOC.

Clinical Characteristics, Outcomes, and Progression to Type 2 Diabetes in Women with Hyperglycemia in Pregnancy

CONTEXT

Women with hyperglycemia in pregnancy (HIP) are at increased risk of developing type 2 diabetes (T2D).

AIM

The present study intended to study the incidence of postpartum diabetes among HIP women and predict its risk factors.

SETTINGS AND DESIGN

This was a prospective observational study done on 178 women with HIP diagnosed after the first trimester, attending the tertiary care hospitals between December 2018 and March 2020.

MATERIALS AND METHODS

Demographics, clinical variables, and feto-maternal outcomes were recorded. The postpartum glycemic status was determined using a 75 g oral glucose tolerance test (OGTT) at 1 and 6 months.

STATISTICAL ANALYSIS

All analyses were performed with SPSS software (version 21.0).

RESULTS

The mean age of women with HIP was 30.2 ± 6.1 years, with 38% having a family history of diabetes. Eighty percent of the women delivered full-term babies and 71.3% underwent a cesarean section. Gestational hypertension was present in 21.9% of patients. Macrosomia was present in 4.6% of the babies, hypoglycemia in 6.7%, and spontaneous abortion occurred in 7.7%. Postpartum OGTT at 6 months was completed by 76.4% of participants. The incidence of diabetes and glucose intolerance postpartum was 11.7 and 16.2%, respectively at 6 months. Logistic regression analysis showed that maternal obesity, diagnosis of HIP at an earlier trimester (<24 weeks), need for insulin treatment during pregnancy, signs of insulin resistance and fasting and 2-h plasma glucose >100 (>5.6 mmol/L) and >195 mg/dL (>10.9 mmol/L), respectively, and glycated hemoglobin > 6.5% (>48 mmol/mol) increased the risk of having postpartum diabetes significantly.

CONCLUSION

The incidence of postpartum glucose intolerance in women with HIP is high. Prospective diabetes evaluation is required and intervention should be considered in women with HIP who have obesity, diagnosis of HIP at an earlier trimester, signs of insulin resistance, and require insulin treatment during pregnancy.

The diagnosis of Gestational Diabetes Mellitus and its impact on In Vitro Fertilization pregnancies. A pilot study

BACKGROUND

In Vitro Fertilization (IVF) is increasingly becoming a necessary mode of reproduction. This high risk group is prone to Gestational Diabetes Mellitus (GDM) which further exposes these pregnancies to an increased risk of adverse outcomes. In light of the limited data in the current literature, further investigation is needed regarding the time of GDM diagnosis in IVF pregnancies as well as the outcome of IVF pregnancies complicated by GDM.

METHODS

In this three center pilot cross sectional study, the data of 101 singleton IVF pregnancies complicated by GDM were analyzed. Prompt GDM diagnosis in IVF pregnancies was accomplished by self-blood glucose monitoring (SMBG) from the first antenatal visit and confirmed by an OGTT. To evaluate pregnancy outcome, maternal and fetal complications in the 101 GDM IVF group was compared to 101 IVF as well as 101 spontaneous conceptions (SC). The three groups were matched by age. The effect of demographic and glycemic parameters on the outcome of GDM IVF pregnancies was investigated.

RESULTS

GDM diagnosis was made before the 24th week in 37.6% of the GDM IVF group. The week of delivery was earlier for the GDM IVF group (37 ± 1.7) relative to the IVF (37.9 ± 0.9, p < 0.001) and the SC group (38.1 ± 0.8, p < 0.001). GDM IVF pregnancies exhibited greater preeclampsia rates and 84.8% underwent caesarian section. No significant difference regarding LGA and SGA birth weights was found. Complications of GDM IVF pregnancies were associated with the 1-h postprandial BG (r = 0.267, p = 0.007).

CONCLUSION

GDM screening in IVF pregnancies may be considered earlier than the 24th week. IVF pregnancies affected by GDM are prone to increased maternal and fetal complications which are associated with 1-h postprandial BG.

Time in Range in Pregnancy: Is There a Role?

Continuous glucose monitoring (CGM) is being used with increasing frequency as an adjunct to self-monitoring of blood glucose in pregnancy, and novel targets based on CGM data are becoming standardized. This adoption of CGM is the result of its improving accuracy, patient preference, and evolving data demonstrating associations of novel targets such as time in range (TIR) with pregnancy and neonatal outcomes. A greater understanding of the relationship of various CGM metrics to outcomes in pregnancy complicated by diabetes is needed. It is clear that TIR parameters need to be uniquely lower for pregnant women than for nonpregnant individuals. CGM technology is also an integral part of hybrid closed-loop insulin delivery systems. These insulin delivery systems will be a significant advance in the management of diabetes during pregnancy if they can achieve the pre- and postprandial targets required for pregnancy and optimize TIR.

Insulin Dosing, Glycemic Control, and Perinatal Outcomes in Pregnancies Complicated by Type-2 Diabetes

OBJECTIVE

This study aimed to evaluate the prevalence of severe insulin resistance (insulin requirements ≥2 units/kg) at delivery and the relationship between severe insulin resistance, glycemic control, and adverse perinatal outcomes in pregnant women with type-2 diabetes mellitus.

STUDY DESIGN

This is a retrospective cohort study of women with type-2 diabetes mellitus who delivered between January 2015 and December 2017 at a tertiary academic medical center. Maternal demographic information, self-monitored blood sugars, and insulin doses were abstracted from the medical record. Multivariable logistic regression was used to identify maternal baseline characteristics associated with severe insulin resistance at delivery.

RESULTS

Overall 72/160 (45%) of women had severe insulin resistance. Women in the severe insulin resistance group demonstrated evidence of suboptimal glycemic control as evidenced by higher mean hemoglobin A1c (HbA1c) values (7.2 [ ±  1.1] vs. 6.6 [ ±  1.3%], p = 0.003), higher mean fasting (104.0 [ ±  17.4] vs. 95.2 [ ±  11.7 mg/dL], p < 0.001) and postprandial glucose values (132.4 [ ±  17.2] vs. 121.9 [ ± 16.9 mg/dL]), p < 0.001), and a higher percentage of total glucose values that were elevated above targets (37.7 [95% confidence interval (CI): 26.8-50] vs. 25.6 [95% CI: 13.3-41.3%], p < 0.001). Maternal HbA1c ≥6.5% and insulin use prior to pregnancy were associated with a higher prevalence of severe insulin resistance, while Hispanic ethnicity and non-White race were associated with a lower prevalence of severe insulin resistance. The rates of adverse perinatal outcomes including large for gestational age (LGA) birth weight, cesarean delivery, and hypertensive disorders of pregnancy did not differ between groups.

CONCLUSION

Severe insulin resistance is common among pregnant women with type-2 diabetes, and it is associated with suboptimal glycemic control. Future studies are necessary to develop strategies to identify women with severe insulin resistance early in pregnancy and facilitate adequate insulin dosing.

KEY POINTS

· Severe insulin resistance is common.. · BMI does not predict severe insulin resistance.. · Suboptimal glycemic control is common..

GLU: a software package for analysing continuously measured glucose levels in epidemiology

Continuous glucose monitors (CGM) record interstitial glucose levels 'continuously', producing a sequence of measurements for each participant (e.g. the average glucose level every 5 min over several days, both day and night). To analyse these data, researchers tend to derive summary variables such as the area under the curve (AUC), to then use in subsequent analyses. To date, a lack of consistency and transparency of precise definitions used for these summary variables has hindered interpretation, replication and comparison of results across studies. We present GLU, an open-source software package for deriving a consistent set of summary variables from CGM data. GLU performs quality control of each CGM sample (e.g. addressing missing data), derives a diverse set of summary variables (e.g. AUC and proportion of time spent in hypo-, normo- and hyper- glycaemic levels) covering six broad domains, and outputs these (with quality control information) to the user. GLU is implemented in R and is available on GitHub at https://github.com/MRCIEU/GLU. Git tag v0.2 corresponds to the version presented here.

Continuous glucose monitoring during pregnancy in healthy mice

During pregnancy, metabolic adaptations occur to maintain the balance between maternal and foetal growth, including increased insulin secretion and decreased insulin sensitivity. When the body fails to adjust, gestational diabetes mellitus develops. To gain insight in the pregnancy-induced adaptations, we applied continuous glucose monitoring via telemetric transmitters. We show that continuous glucose monitoring in conscious, non-stressed, freely moving mice throughout the full pregnancy is feasible, accurate and safe. We show that healthy mice during a full pregnancy develop adaptations in glucose homeostasis reminiscent of those in pregnant women. Furthermore, continuous glucose monitoring allows the complete analysis of all aspects of glucose excursions associated with spontaneous feeding episodes, and the thorough analysis of glycaemic variability. In conclusion, continuous glucose monitoring allows a detailed description of the glycaemic status during pregnancy, which will help to unravel specific mechanisms for gestational diabetes mellitus.

Prenatal exposure to ambient air pollution and adverse pregnancy outcomes in Ahvaz, Iran: a generalized additive model

OBJECTIVE

There is some evidence about the short-term effects of air pollutants on adverse pregnancy outcomes. The aim of this study was to determine the association between air pollutants and spontaneous abortion, stillbirth, gestational hypertension, preeclampsia, gestational diabetes and macrosomia in Ahvaz, which is one of the most polluted cities in the Middle East.

METHODS

Data on adverse pregnancy outcomes and air pollutants including ozone (O3), nitric oxide (NO), nitrogen dioxide (NO2), sulfur dioxide (SO2), carbon monoxide (CO), particles with a diameter of less than 10 µm (PM10) and particles with a diameter less than 2.5 µm (PM2.5) were inquired from the Health Department of Ahvaz Jundishapur University of Medical Sciences and the Environmental Protection Agency of Khuzestan Province for the years 2008-2018. A time series analysis using the generalized additive model (GAM) with up to 6-day lags was used.

RESULTS

The results showed that the SO2 pollutant on 0, 1, 3, 4, and 6-day lags and PM10 on lag 0 had direct and significant associations with spontaneous abortion. NO, NO2 and CO on 0-6-day lags, and O3 on 6-day lags showed direct and significant associations with preeclampsia. NO and NO2 pollutants showed significant and direct associations with gestational diabetes, during 0- and 6-day lags. NO on 0-, 3- and 4-day lags, CO in all 0-6-day lags and PM2.5 on 1-, 3-, 5-, and 6-day lags showed direct and significant associations with macrosomia. None of the pollutants showed significant associations with stillbirth or gestational hypertension.

CONCLUSIONS

The results of this study suggest that some air pollutants are associated with spontaneous abortion, preeclampsia, gestational diabetes and macrosomia. This study further emphasizes the need to control ambient air pollution.

Searching for Utopia, the Challenge of Standardized Medical Nutrition Therapy Prescription in Gestational Diabetes Mellitus Management: A Critical Review

Gestational diabetes mellitus (GDM) is a common pregnancy disorder and the incidence is increasing worldwide. GDM is associated with adverse maternal outcomes which may be reduced with proper management. Lifestyle modification in the form of medical nutrition therapy and physical activity, as well as self-monitoring of blood glucose levels, is the cornerstone of GDM management. Inevitably, the search for the "ultimate" diet prescription has been ongoing. Identifying the amount and type of carbohydrate to maintain blood glucose levels below targets while balancing the nutritional requirements of pregnancy and achieving gestational weight gain within recommendations is challenging. Recent developments in the area of the gut microbiota and its impact on glycemic response add another layer of complexity to the success of medical nutrition therapy. This review critically explores the challenges to dietary prescription for GDM and why utopia may never be found.

14. Management of Diabetes in Pregnancy: Standards of Medical Care in Diabetes-2021

The American Diabetes Association (ADA) "Standards of Medical Care in Diabetes" includes the ADA's current clinical practice recommendations and is intended to provide the components of diabetes care, general treatment goals and guidelines, and tools to evaluate quality of care. Members of the ADA Professional Practice Committee, a multidisciplinary expert committee (https://doi.org/10.2337/dc21-SPPC), are responsible for updating the Standards of Care annually, or more frequently as warranted. For a detailed description of ADA standards, statements, and reports, as well as the evidence-grading system for ADA's clinical practice recommendations, please refer to the Standards of Care Introduction (https://doi.org/10.2337/dc21-SINT). Readers who wish to comment on the Standards of Care are invited to do so at professional.diabetes.org/SOC.

The effects of health care programs for gestational diabetes mellitus in South Korea: a systematic review

Purpose

The purpose of this study was to investigate the effects and characteristics of health care programs for pregnant women with gestational diabetes mellitus (GDM) in Korea.

Methods

This study was conducted according to the Cochrane Collaboration's systematic literature review handbook and the Preferred Reporting Items for Systematic Reviews and Meta-Analyses reporting guideline. We searched eight international and domestic electronic databases for relevant studies. Two reviewers independently selected the studies and extracted data. For each study, information on the research method, participants, characteristics of the program, and results were extracted using a previously established coding table. The National Evidence-based Healthcare Collaborating Agency's risk of bias assessment tool for non-randomized studies was used to assess the risk of bias of the included articles. A qualitative review of the selected studies was performed because the interventions differed considerably and the measured outcomes varied.

Results

Out of 128 initially identified papers, seven were included in the final analysis. The risk of bias was evaluated as generally low. Health care programs for pregnant women with GDM showed positive effects on blood glucose control. Anxiety and depression were reduced, and self-management and self-care behavior, self-efficacy, and maternal identity improved.

Conclusion

Our study provides clinical evidence for the effectiveness of health care programs for pregnant women with GDM, and its results can be used to support the development of health care programs for GDM. More well-designed research is needed on GDM, especially studies that deal with emotional stress and apply a family-oriented approach.

Glycemic profile of women with normoglycemia and gestational diabetes mellitus during early pregnancy using continuous glucose monitoring system

AIM

We studied women between 8 and 20 weeks of gestation with the aim of evaluating and comparing those having normoglycemia and GDM according to WHO 2013 criteria.

METHODS

In this cross-sectional study (2017-2019), eligible pregnant women underwent a 75-g OGTT, followed by placement of a CGMS.

RESULTS

Women (n = 96, 58 with normoglycemia and 38 with GDM) were enrolled at 14.0 ± 3.2 weeks of gestation. Mean preprandial, 1-h and 2-h postprandial and peak glucose values were significantly higher in women with GDM. Peak glucose value was achieved 60.0 ± 12.3 and 64.3 ± 11.6 min after meal in the normoglycemia and GDM group, respectively. 24-h mean glucose (5.8 ± 0.6 vs. 5.3 ± 0.4 mmol/L), mean daytime glucose (6.0 ± 0.6 vs. 5.5 ± 0.4 mmol/L) and mean nocturnal glucose (5.4 ± 0.7 vs. 5.0 0 ± 0.5 mmol/L) were significantly higher in women with GDM. Total time spent in range was significantly lower in the GDM group compared to the normoglycemia group (92.1 vs. 98.2%).

CONCLUSIONS

This study highlights differences in glycemic patterns between women with normoglycemia and GDM in the context of a South Asian population where burden of GDM is high but good quality data in early pregnancy are limited.

Continuous Glucose Monitoring Versus Self-Monitoring of Blood Glucose to Assess Glycemia in Gestational Diabetes

Background: Gestational diabetes mellitus (GDM) management using self-monitoring blood glucose (SMBG) does not normalize pregnancy outcomes. Objective: We aimed to conduct an observational study to explore if continuous glucose monitoring (CGM) could identify elevated glucose levels not apparent in women with GDM managed using SMBG. Study Design: A 7-day masked-CGM (iPro; Medtronic) was performed within 2 weeks of GDM diagnosis, immediately post-GDM education, but before insulin commencement as determined by SMBG. CGM data regarding hyperglycemia (sensor glucose >126 mg/dL [06:00-00:00 h] and >99 mg/dL [00:00-06:00 h] for >10% of time), time with health care professionals, treatment, and pregnancy outcome were collected. Comparisons (Mann-Whitney test) were performed between subjects subsequently commenced on insulin versus those continued with diet and lifestyle measures alone. Results: Ninety women of mean (standard deviation) gestational age weeks 27(1) were studied. Those prescribed insulin (n = 34) compared with those managed with diet and lifestyle alone (n = 56) had a greater time in hyperglycemia (P = 0.0001). Of those not prescribed insulin, 35/56 (61%) breached CGM cutoffs between 00:00 and 06:00 h; 11/56 (20%) breached 6.00-00.00 h CGM cutoffs for >10% of the time; and 21/45 (47%) with optimal CGM glucose levels during the daytime spent >10% time in hyperglycemia between 00.00 and 06:00 h. In contrast, SMBG measurements exceeded the clinical targets of <120 mg/dL postdinner in 5.4% and <100 mg/dL fasting in 0% of the subjects. Conclusions: CGM provides a more comprehensive assessment of nocturnal hyperglycemia than SMBG and could improve targeting of interventions in GDM. Larger studies to better define CGM targets are required, which once established will inform studies aimed at targeting nocturnal glucose levels.

Ambient air pollution exposure associated with glucose homeostasis during pregnancy and gestational diabetes mellitus

BACKGROUND

To investigate the effects of air pollution exposure during pregnancy on the indicators of glucose homeostasis and gestational diabetes mellitus (GDM).

METHODS

We conducted a birth cohort study in Foshan, China during 2015-2019. Oral glucose tolerance test (OGTT) was administered to each participant during pregnancy. GDM was defined according to the International Association of Diabetes and Pregnancy Study Groups criteria (IADPSG). Air pollutant (fine particulate matter (PM_2.5), particulate matter with an aerodynamic diameter of 10 μm or less (PM₁₀), sulfate dioxide (SO₂), nitrogen dioxide (NO₂) and ozone (O₃)) concentrations from the air monitoring stations in Foshan were used to estimate individual air pollutant exposure during the first two trimesters. Linear and logistic regression models were employed to estimate the associations between air pollution exposure during the first two trimesters and OGTT glucose levels and GDM.

RESULTS

Of 12,842 pregnant women, 3055 (23.8%) had GDM. A 10 μg/m³ increase in PM_2.5, PM₁₀ and SO₂ during trimester 1, trimester 2 and two trimesters were associated with 0.07 mmol/L to 0.29 mmol/L increment in OGTT-fasting glucose levels in single-pollutant model. A 10 μg/m³ increase in NO₂ and O₃ during two trimesters were associated with 0.15 mmol/L and 0.12 mmol/L decrease in OGTT-fasting glucose in single-pollutant model. However, no significant or weaker effects of O₃ during two trimesters on OGTT-fasting glucose were observed in two-pollutant models. Moreover, exposure to PM_2.5, PM₁₀ and SO₂ were associated with increased risk of GDM in both single- and two-pollutant models.

CONCLUSIONS

Our study suggests PM_2.5, PM₁₀ and SO₂ exposure during the first two trimesters might increase the risk of GDM.

Insulin Therapy and Diabetic Pregnancy

BACKGROUND

A good metabolic control before conception and throughout pregnancy with diabetes decreases the risk of short- and long-term adverse outcomes of the mothers and their offsprings. Insulin treatment remains the gold standard treatment recommended for any type of diabetes. New technologies including new insulins and insulin analogues, continuous subcutaneous insulin infusion without and with sensors, the low-glucose predictive suspension function, and closed-loop systems that persistently and automatically self-adjust according to patients' continuous glucose monitoring readings have expanded the offer to clinicians for achieving tight glucose control.

AREAS OF UNCERTAINTY

Unsafe effects of insulin and insulin analogues in pregnancy with diabetes could be linked with changes in insulin immunogenicity, teratogenicity, and mitogenicity. Second-generation insulin analogues need to be tested and proven. Effectiveness and safety of new insulin delivery systems in real life of diabetic women in pregnancy need further confirmations.

SOURCES

MEDLINE, EMBASE, Web of Science, Cochrane Library, randomized controlled trials, systematic review and meta-analysis, observational prospective and retrospective studies, case series reports for the most recent insulin analogues, published in English impacted journals, and consensus statements from scientific societies I excluded 60 from 221 papers as not suitable for the purpose of the subject.

RESULTS

Subcutaneous insulin infusion can be safely used during pregnancy and delivery of well-trained women. Sensors are increasingly accurate tools that improve the efficacy and safety of integrated systems' functioning. Continuous glucose monitoring provides metrics ("time in range" time in "hypoglycemia" and in "hyperglycemia," glucose variability, average glucose levels in different time intervals) used as a guide to diabetes management; these new metrics are object of discussion in special populations. Randomized controlled trials have shown that sensor-augmented pump therapy improves pregnancy outcomes in women with type 1 diabetes. Closed-loop insulin delivery provides better glycemic control than sensor-augmented pump therapy during pregnancy, before, and after delivery.

CONCLUSION

Second-generation insulin analogues and newer insulin infusion systems that automatically self-adjust according to patients continuous glucose monitor readings are important tools improving the treatment and quality of life of these women. Multi-institutional and disciplinary teams are working to develop and evaluate a pregnancy-specific artificial pancreas.

Intensive glycemic control in gestational diabetes mellitus: a randomized controlled clinical feasibility trial

BACKGROUND

Overweight and obese women with gestational diabetes mellitus are at increased risk for adverse perinatal outcomes, and they are also more likely to have suboptimal glycemic control. However, there is a paucity of data evaluating whether lower glycemic targets could improve outcomes.

OBJECTIVE

To evaluate the feasibility of intensive glycemic control in overweight and obese women with gestational diabetes mellitus.

MATERIALS AND METHODS

We randomized 60 overweight or obese women with gestational diabetes mellitus, diagnosed between 12 and 32 weeks' gestation to either intensive (fasting <90 mg/dL, 1 hour postprandial <120 mg/dL) or standard (fasting <95 mg/dL, 1 ho postprandial <140 mg/dL) glycemic targets. Maternal glucose was assessed in 2 ways: blinded continuous glucose monitors, worn for 5 days at 2 time points (at 12-32 weeks and again at 32-36 weeks), and self-monitored glucose measurement 4 times per day. All women underwent standardized dietary counseling, and medical therapy was prescribed as needed to achieve glycemic control.

RESULTS

Between December 2015 and December 2017, we randomized 60 women to either intensive (n = 30) or standard (n = 30) glycemic control. Baseline characteristics including maternal age, body mass index, and gestational age at diagnosis were similar between the intensive and standard groups. Medical therapy was more common in women in the intensive group than those in the standard group (83 vs 57%, P = .02). Women in the intensive glycemic control group had lower glucose values as assessed by continuous glucose monitors at including 24-hour mean (-8.1; 95% confidence interval, -12.0 to -4.3 mg/dL; P < .0001) and 1-h postprandial (-11.8; 95% confidence interval, -19.7 to -3.9 mg/dL, P = .004) values. Hypoglycemia <60 mg/dL was uncommon and did not differ between groups.

CONCLUSION

Intensive glycemic targets can be used in overweight and obese women with minimal hypoglycemia, and this approach results in improved glycemic control when compared to standard glycemic targets. Further studies are needed to determine whether intensive glycemic targets can improve maternal and neonatal outcomes in high-risk women with gestational diabetes mellitus.

CLINICAL TRIAL IDENTIFIER

NCT02530866; clinicaltrials.gov.

Continuous glucose monitoring targets in type 1 diabetes pregnancy: every 5% time in range matters

With randomised trial data confirming that continuous glucose monitoring (CGM) is associated with improvements in maternal glucose control and neonatal health outcomes, CGM is increasingly used in antenatal care. Across pregnancy, the ambition is to increase the CGM time in range (TIR), while reducing time above range (TAR), time below range (TBR) and glycaemic variability measures. Pregnant women with type 1 diabetes currently spend, on average, 50% (12 h), 55% (13 h) and 60% (14 h) in the target range of 3.5-7.8 mmol/l (63-140 mg/dl) during the first, second and third trimesters, respectively. Hyperglycaemia, as measured by TAR, reduces from 40% (10 h) to 33% (8 h) during the first to third trimester. A TIR of >70% (16 h, 48 min) and a TAR of <25% (6 h) is achieved only in the final weeks of pregnancy. CGM TBR data are particularly sensor dependent, but regardless of the threshold used for individual patients, spending ≥4% of time (1 h) below 3.5 mmol/l or ≥1% of time (15 min) below 3.0 mmol/l is not recommended. While maternal hyperglycaemia is a well-established risk factor for obstetric and neonatal complications, CGM-based risk factors are emerging. A 5% lower TIR and 5% higher TAR during the second and third trimesters is associated with increased risk of large for gestational age infants, neonatal hypoglycaemia and neonatal intensive care unit admissions. For optimal neonatal outcomes, women and clinicians should aim for a TIR of >70% (16 h, 48 min) and a TAR of <25% (6 h), from as early as possible during pregnancy.