Novel Biochemical Markers of Glycemia to Predict Pregnancy Outcomes in Women With Type 1 Diabetes

Mean Glucose and Gestational Weight Gain as Predictors of Large-for-Gestational-Age Infants in Pregnant Women with Type 1 Diabetes Using Continuous Glucose Monitoring

Aims/hypothesis: To compare glycemic metrics during pregnancy between women with type 1 diabetes (T1D) delivering large-for-gestational-age (LGA) and appropriate-for-gestational-age (AGA) infants, and to identify predictors of LGA infants. Materials and Methods: A cohort study including 111 women with T1D using intermittently scanned continuous glucose monitoring from conception until delivery. Average sensor-derived metrics: mean glucose, time in range in pregnancy (TIRp), time above range in pregnancy, time below range in pregnancy, and coefficient of variation throughout pregnancy and in pregnancy intervals of 0-10, 11-21, 22-33, and 34-37 weeks were compared between women delivering LGA and AGA infants. Predictors of LGA infants were sought for. Infant growth was followed until 3 months postdelivery. Results: In total, 53% (n = 59) delivered LGA infants. Mean glucose decreased during pregnancy in both groups, with women delivering LGA infants having a 0.4 mmol/L higher mean glucose from 11-33 weeks (P = 0.01) compared with women delivering AGA infants. Mean TIRp >70% was obtained from 34 weeks in women delivering LGA infants and from 22-33 weeks in women delivering AGA infants. Independent predictors for delivering LGA infants were mean glucose throughout pregnancy and gestational weight gain. At 3 months postdelivery, infant weight was higher in infants born LGA compared with infants born AGA (6360 g ± 784 and 5988 ± 894, P = 0.04). Conclusions/interpretations: Women with T1D delivering LGA infants achieved glycemic targets later than women delivering AGA infants. Mean glucose and gestational weight gain were independent predictors for delivering LGA infants. Infants born LGA remained larger postdelivery compared with infants born AGA.

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.

Serum betaine and dimethylglycine in mid-pregnancy and the risk of gestational diabetes mellitus: a case-control study

PURPOSE

To investigate the associations of choline, betaine, dimethylglycine (DMG), L-carnitine, and Trimethylamine-N-oxide (TMAO) with the risk of Gestational diabetes mellitus (GDM) as well as the markers of glucose homeostasis.

METHODS

We performed a case-control study including 200 diagnosed GDM cases and 200 controls matched by maternal age (±2 years) and gestational age (±2 weeks). Concentrations of serum metabolites were measured by the high-performance liquid chromatography - tandem mass spectrometry (HPLC-MS/MS).

RESULTS

Compared to the control group, GDM group had significantly lower serum betaine concentration and betaine/choline ratio, and higher DMG concentration. Furthermore, decreased betaine concentration and betaine/choline ratio, increased DMG concentration showed significant association with the risk of GDM. In addition, serum betaine concentrations were negatively associated with blood glucose levels at 1-h post-glucose load (OGTT-1h), and both betaine and L-carnitine concentrations were positively associated with 1,5-anhydroglucitol levels. Betaine/choline ratio was negatively associated with OGTT-1h and blood glucose levels at 2-h post-glucose load (OGTT-2h) and serum choline concentrations were negatively associated with fasting blood glucose and positively associated with OGTT-2h.

CONCLUSION

Decreased serum betaine concentrations and betaine/choline ratio, and elevated DMG concentrations could be significant risk factors for GDM. Furthermore, betaine may be associated with blood glucose regulation and short-term glycemic fluctuations.

A review of CONCEPTT study findings including subanalyses in pregnant women using continuous glucose monitoring with type 1 diabetes and their offspring

The main objective of this article is to provide a comprehensive review of continuous glucose monitor (CGM) use in pregnant women with type 1 diabetes (T1D) from the CONCEPTT study including subanalyses. Literature search was accessed through MEDLINE (1966-September 2023) using the key terms: CONCEPTT, pregnancy, women, T1D, and CGM with limitations set to distinguish human subjects written in English. A total of 17 publications including one main clinical trial and 15 subanalyses have been published to date regarding the use of CGM in pregnant women with T1D which were conducted by a research group identified as the CONCEPTT Collaborative Group. While advances in maternal care have resulted in safer pregnancy for both the mother and child, women with preexisting T1D and pregnancy still experience higher rates of complications both in the short and long term. The use of CGM in pregnancy has not been studied extensively until more recently. The CONCEPTT clinical trial was a landmark study that involved several subanalyses. The main trial proved that CGM use in T1D pregnancy resulted in less hyperglycemia in the third trimester, reduced large for gestational age (LGA, >90th percentile), reduced neonatal intensive care unit admissions lasting longer than 24 h, and reduced neonatal hypoglycemia. Although subanalyses showed a variety of results including 'inconclusive' due to lack of prespecification, it is believed that CGM in T1D during pregnancy is to be recommended and used for overall improved outcomes.

Effect of artificial pancreas system use on glycaemic control among pregnant women with type 1 diabetes mellitus: A meta-analysis of randomized controlled trials

AIM

To assess the efficacy of artificial pancreas systems (APS) use among pregnant women with type 1 diabetes mellitus (T1DM) by conducting a meta-analysis.

METHODS

We searched five databases, including EMBASE, Web of Science, PubMed, Cochrane Library and SCOPUS, for literature on APS use among pregnant women with T1DM before October 9, 2023. The primary endpoint was 24-hour time in range (TIR; 3.5-7.8 mmol/L). Secondary endpoints included glycaemic metrics for 24-hour (mean blood glucose [MBG], time above range [TAR], time below range [TBR]), and overnight TIR and TBR.

RESULTS

We identified four randomized controlled trials involving 164 participants; one study with 16 participants focused on overnight APS use, and the other three focused on 24-hour APS use. Compared with standard care, APS exhibited a favourable effect on 24-hour TIR (standard mean difference [SMD] = 0.53, 95% confidence interval [CI] 0.25, 0.80, P < 0.001), overnight TIR (SMD = 0.67, 95% CI 0.39, 0.95, P < 0.001), and overnight TBR (<3.5 mmol/L; SMD = -0.49, 95% CI -0.77, -0.21 P < 0.001), while there was no significant difference in 24-hour TAR, 24-hour TBR, or MBG between the two groups. We further conducted subgroup analyses after removing the trial focused on overnight APS use and showed that 24-hour APS use reduced not only the 24-hour TIR (SMD = 0.41, 95% CI 0.12, 0.71; P = 0.007) but also the 24-hour TBR (<2.8 mmol/L; SMD = -0.77, 95% CI -1.32, -0.23, P = 0.006).

CONCLUSION

Our findings suggest that APS might improve 24-hour TIR and overnight glycaemic control, and 24-hour APS use also significantly reduced 24-hour TBR (2.8 mmol/L) among pregnant women with T1DM.

Continuous glucose monitoring in pregnancies with type 1 diabetes: small increases in time-in-range improve maternal and perinatal outcomes

BACKGROUND

Continuous glucose monitors provide detailed information regarding glycemic control in pregnant patients with type 1 diabetes. Little data have been published examining the association between continuous glucose monitor parameters and perinatal outcomes among gravidas with type 1 diabetes using continuous glucose monitors.

OBJECTIVE

This study aimed to examine the association between perinatal outcomes and time-in-range as assessed by continuous glucose monitors used in pregnant individuals with type 1 diabetes. We hypothesized that higher time-in-range would be associated with lower risk of adverse perinatal outcomes.

STUDY DESIGN

This multicenter retrospective cohort study included all gravidas with type 1 diabetes using continuous glucose monitors who delivered from 2020 to 2022 at 5 University of California sites. Only those with continuous glucose monitor target range set to 70 to 140 mg/dL (±10 mg/dL) were included. Time-in-range (%) was recorded at 12, 16, 20, 24, 28, and 32 weeks. The primary maternal and neonatal outcomes were preeclampsia and large for gestational age, defined as birthweight ≥95th percentile. Kruskal-Wallis tests were used to compare median time-in-range between those with and without the primary outcomes. Log-binomial regression was used to obtain risk ratios, with adjustment for microvascular disease and years with type 1 diabetes.

RESULTS

A total of 91 patients were included. Most used an insulin pump (81%) and did not have diabetic microvascular disease (72%). Median time since diagnosis of type 1 diabetes was 16 years, and median periconception hemoglobin A1c was 6.7%. Compared with those with preeclampsia, normotensive gravidas had significantly higher time-in-range at nearly every time point. A similar pattern was observed for those with normal-birthweight infants compared with large-for-gestational-age infants. On adjusted analyses, every 5-unit increase in time-in-range at 12 weeks was associated with 45% and 46% reductions in the risks of preeclampsia and large for gestational age, respectively (preeclampsia: adjusted risk ratio, 0.55; 95% confidence interval, 0.30-0.99; large for gestational age: adjusted risk ratio, 0.54; 95% confidence interval, 0.29-0.99).

CONCLUSION

Higher time-in-range is associated with lower risk of preeclampsia and large for gestational age. This association is observed early in gestation, when each 5-unit increase in time-in-range is associated with ∼50% reduction in the risk of these complications. These findings can be used to counsel patients regarding the risk of pregnancy complications at specific time-in-range values, and to encourage patients that even small improvements in time-in-range can have significant impact on pregnancy outcomes. Larger studies are needed to further explore these findings and to identify optimal time-in-range to reduce perinatal complication rates.

Association of Continuous Glucose Monitoring Metrics With Pregnancy Outcomes in Patients With Preexisting Diabetes

OBJECTIVE

Continuous glucose monitoring (CGM) improves maternal glycemic control and neonatal outcomes in type 1 diabetes pregnancies compared with self-monitoring of blood glucose. However, CGM targets for pregnancy are based on expert opinion. We aimed to evaluate the association between CGM metrics and perinatal outcomes and identify evidence-based targets to reduce morbidity.

RESEARCH DESIGN AND METHODS

This was a retrospective cohort study of pregnant patients with type 1 or 2 diabetes who used real-time CGM and delivered at a U.S. tertiary center (2018-2021). Multiple gestations, fetal anomalies, and early pregnancy loss were excluded. Exposures included time in range (TIR; 65-140 mg/dL), time above range (TAR), time below range (TBR), glucose variability, average glucose, and glucose management indicator. The primary outcome was a composite of fetal or neonatal mortality, large or small for gestational age at birth, neonatal intensive care unit admission, hypoglycemia, shoulder dystocia or birth trauma, and hyperbilirubinemia. Logistic regression estimated the association between CGM metrics and outcomes, and optimal TIR was calculated.

RESULTS

Of 117 patients, 16 (13.7%) used CGM before pregnancy and 68 (58.1%) had type 1 diabetes. Overall, 98 patients (83.8%) developed the composite neonatal outcome. All CGM metrics, except TBR, were associated with neonatal morbidity. For each 5 percentage-point increase in TIR, there was 28% reduced odds of neonatal morbidity (odds ratio 0.72, 95% CI 0.58-0.89). The statistically optimal TIR was 66-71%.

CONCLUSIONS

Nearly all CGM metrics were associated with adverse neonatal morbidity and mortality and may aid management of preexisting diabetes in pregnancy. Our findings support the American Diabetes Association recommendation of 70% TIR.

Functional analysis of daily glycemic profiles and excessive fetal growth in pregnant patients with well-controlled type 1 diabetes: Retrospective cohort

AIMS

The study objective was to compare daily glycemic profiles throughout gestation between the mothers of large-for-gestational-age (LGA) and non-LGA newborns in patients with type 1 diabetes (T1D).

METHODS

We selected 102 eligible pregnant women who were treated with sensor-augmented pumps in our single-center retrospective cohort study. We used functional data analysis to compare glycemic control across gestation.

RESULTS

Median HbA1c values in the first, second, and third trimester were 6.23 %, 5.49 %, and 5.75 % respectively. Median time-in-range (TIR) exceeded 70 % in each trimester (72.4 %, 72.5 %, and 75.9 %, respectively). From 59 % up to 77 % of women met the criteria for well-controlled T1D defined by the mean HbA1c and TIR in each trimester. Despite that, 27 % (28/102) of pregnancies were complicated by LGA. Mothers of LGA infants had significantly increased HbA1c levels and decreased TIR values in the second and third trimesters. The most significant differences in daily mean glucose values between LGA and non-LGA newborns' mothers occurred between 26 and 32 weeks of pregnancy. These discrepancies were noted in daytime glucose values rather than nocturnal and fasting glucose levels.

CONCLUSIONS

Mothers of LGA newborns present significantly worse glycemic control. Our findings may emphasize the need for more rigorous daytime glycemic control.

Continuous Glucose Monitoring Metrics in High-Risk Pregnant Women with Type 2 Diabetes

Objective: To describe glucose metrics in a high-risk population of women with type 2 diabetes (T2DM) in pregnancy and to explore the associations with neonatal outcomes. Research Design and Methods: Prospective observational study of 57 women. Continuous glucose monitoring (CGM) trajectories were determined from metrics collected in early and late gestation using the first and last two (mean 16 and 35) weeks of Freestyle Libre data. Logistic regression was used to examine associations of CGM metrics with neonatal hypoglycemia (glucose <2.6 mmol/L requiring intravenous dextrose) and large for gestational age (LGA) (>90th percentile for gestational age and sex). Pregnancy-specific target glucose range was 3.5-7.8 mmol/L (63-140 mg/dL). Results: Forty-one women used CGM for 15 weeks (mean age 33 years, 73% Aboriginal or Torres Strait Islander, 32% living remotely). There was limited change in average metrics from early to late pregnancy. For the subgroup with sensor use >50% (n = 29), mean time in range (TIR) increased by 9%, time above range reduced by 12%, average glucose reduced by 1 mmol/L, and time below range increased by 3%. Neonatal hypoglycemia was associated with most CGM metrics, HbA1c and CGM targets, particularly those from late pregnancy. LGA was associated with hyperglycemic metrics from early pregnancy. Each 1% increase TIR was associated with a 4%-5% reduction in risk of neonatal complications. Conclusion: In this high-risk group of women with T2DM, CGM metrics only improved during pregnancy in those with greater sensor use and were associated with LGA in early pregnancy and neonatal hypoglycemia throughout. Culturally appropriate health care strategies are critical for successful use of CGM technology.

Continuous glucose monitoring metrics and pregnancy outcomes in insulin-treated diabetes: A post-hoc analysis of the GlucoMOMS trial

AIM

To investigate the association between continuous glucose monitoring (CGM) metrics and perinatal outcomes in insulin-treated diabetes mellitus in pregnancy.

MATERIALS AND METHODS

In a post-hoc analysis of the GlucoMOMS randomized controlled trial, we investigated the association between the metrics of an offline, intermittent CGM, glycated haemoglobin (HbA1c) and perinatal outcomes per trimester in different types of diabetes (type 1, 2 or insulin-treated gestational diabetes mellitus [GDM]). Data were analysed using multivariable binary logistic regression. Outcomes of interest were neonatal hypoglycaemia, pre-eclampsia, preterm birth, large for gestational age (LGA) and Neonatal Intensive Care Unit (NICU) admission. The glucose target range was defined as 3.5-7.8 mmol/L (63-140 mg/dL).

RESULTS

Of the 147 participants (N = 50 type 1 diabetes, N = 94 type 2 diabetes/insulin-treated GDM) randomized to the CGM group of the GlucoMOMS trial, 115 participants had CGM metrics available and were included in the current study. We found that, in pregnancies with type 1 diabetes, a higher second trimester mean glucose was associated with LGA (odds ratio 2.6 [95% confidence interval 1.1-6.2]). In type 2 and insulin-treated gestational diabetes, an increased area under the curve above limit was associated with LGA (odds ratio 10.0 [95% confidence interval 1.4-72.8]). None of the CGM metrics were associated with neonatal hypoglycaemia, pre-eclampsia, shoulder dystocia, preterm birth and NICU admission rates for pregnancies complicated by any type of diabetes.

CONCLUSION

In this study, in type 2 diabetes or insulin-treated GDM, the glucose increased area under the curve above limit was associated with increased LGA. In type 1 diabetes, the mean glucose was the major determinant of LGA. Our study found no evidence that other CGM metrics determined adverse pregnancy outcomes.

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.

Metabolomic insights into maternal and neonatal complications in pregnancies affected by type 1 diabetes

AIMS/HYPOTHESIS

Type 1 diabetes in pregnancy is associated with suboptimal pregnancy outcomes, attributed to maternal hyperglycaemia and offspring hyperinsulinism (quantifiable by cord blood C-peptide). We assessed metabolomic patterns associated with risk factors (maternal hyperglycaemia, diet, BMI, weight gain) and perinatal complications (pre-eclampsia, large for gestational age [LGA], neonatal hypoglycaemia, hyperinsulinism) in the Continuous Glucose Monitoring in Women with Type 1 Diabetes in Pregnancy Trial (CONCEPTT).

METHODS

A total of 174 CONCEPTT participants gave ≥1 non-fasting serum sample for the biorepository at 12 gestational weeks (147 women), 24 weeks (167 women) and 34 weeks (160 women) with cord blood from 93 infants. Results from untargeted metabolite analysis (ultrahigh performance LC-MS) are presented as adjusted logistic/linear regression of maternal and cord blood metabolites, risk factors and perinatal complications using a modified Bonferroni limit of significance for dependent variables.

RESULTS

Maternal continuous glucose monitoring time-above-range (but not BMI or excessive gestational weight gain) was associated with increased triacylglycerols in maternal blood and increased carnitines in cord blood. LGA, adiposity, neonatal hypoglycaemia and offspring hyperinsulinism showed distinct metabolite profiles. LGA was associated with increased carnitines, steroid hormones and lipid metabolites, predominantly in the third trimester. However, neonatal hypoglycaemia and offspring hyperinsulinism were both associated with metabolite changes from the first trimester, featuring triacylglycerols or dietary phenols. Pre-eclampsia was associated with increased abundance of phosphatidylethanolamines, a membrane phospholipid, at 24 weeks.

CONCLUSIONS/INTERPRETATION

Altered lipid metabolism is a key pathophysiological feature of type 1 diabetes pregnancy. New strategies for optimising maternal diet and insulin dosing from the first trimester are needed to improve pregnancy outcomes in type 1 diabetes.

An unwelcome inheritance: childhood obesity after diabetes in pregnancy

Diabetes in pregnancy affects 20 million women per year and is associated with increased risk of obesity in offspring, leading to insulin resistance and cardiometabolic disease. Despite the substantial public health ramifications, relatively little is known about the pathophysiological mechanisms underlying obesity in these high-risk children, which creates a barrier to successful intervention. While maternal glucose itself is undeniably a major stimulus upon intrauterine growth, the degree of offspring hyperinsulinism and disturbed lipid metabolism in mothers and offspring are also likely to be implicated in the disease process. The aim of this review is to summarise current understanding of the pathophysiology of childhood obesity after intrauterine exposure to maternal hyperglycaemia and to highlight possible opportunities for intervention. I present here a new unified hypothesis for the pathophysiology of childhood obesity in infants born to mothers with diabetes, which involves self-perpetuating twin cycles of pancreatic beta cell hyperfunction and altered lipid metabolism, both acutely and chronically upregulated by intrauterine exposure to maternal hyperglycaemia.

Management of type 1 diabetes in pregnancy: update on lifestyle, pharmacological treatment, and novel technologies for achieving glycaemic targets

Glucose concentrations within target, appropriate gestational weight gain, adequate lifestyle, and, if necessary, antihypertensive treatment and low-dose aspirin reduces the risk of pre-eclampsia, preterm delivery, and other adverse pregnancy and neonatal outcomes in pregnancies complicated by type 1 diabetes. Despite the increasing use of diabetes technology (ie, continuous glucose monitoring and insulin pumps), the target of more than 70% time in range in pregnancy (TIRp 3·5-7·8 mmol/L) is often reached only in the final weeks of pregnancy, which is too late for beneficial effects on pregnancy outcomes. Hybrid closed-loop (HCL) insulin delivery systems are emerging as promising treatment options in pregnancy. In this Review, we discuss the latest evidence on pre-pregnancy care, management of diabetes-related complications, lifestyle recommendations, gestational weight gain, antihypertensive treatment, aspirin prophylaxis, and the use of novel technologies for achieving and maintaining glycaemic targets during pregnancy in women with type 1 diabetes. In addition, the importance of effective clinical and psychosocial support for pregnant women with type 1 diabetes is also highlighted. We also discuss the contemporary studies examining HCL systems in type 1 diabetes during pregnancies.

Impaired hypoglycaemia awareness in early pregnancy increases risk of severe hypoglycaemia in the mid-long term postpartum irrespective of breastfeeding status in women with type 1 diabetes

INTRODUCTION

Information regarding the postpartum period in women with type 1 diabetes (T1D) is scarce. We aim to evaluate the relation of impaired hypoglycaemia awareness (IAH) in early pregnancy and breastfeeding status (its presence and duration) with severe postpartum hypoglycaemia (SH).

MATERIALS AND METHODS

Retrospective cohort study of women with T1D followed during pregnancy between 2012 and 2019. Data on SH were recorded before and during pregnancy. IAH was evaluated at the first antenatal visit. Data on breastfeeding and the long-term postpartum period were collected by questionnaire and from medical records.

RESULTS

A total of 89 women with T1D were included with a median follow-up after pregnancy of 19.2 [8.7-30.5] months. Twenty-eight (32%) women had IAH at the first antenatal visit. At discharge, 74 (83%) started breastfeeding during a median of 8 [4.4-15] months. A total of 18 (22%) women experienced ≥1 SH during postpartum. The incidence of SH significantly increased from pregestational to the gestational and post-partum period (0.09, 0.15 and 0.25 episodes/patient-year, respectively). Postpartum SH rates were comparable in breastfeeding and non-breastfeeding women (21.4% vs. 25%, respectively, p>0.05). Clarke test score at the first antenatal visit was associated with postpartum SH (for each 1-point increase: OR 1.53; 95% CI, 1.06-2.21) adjusted for confounders. No other diabetes and pregnancy-related variables were identified as predictors of SH in this period.

CONCLUSIONS

SH are common in the long-term postpartum period independently of breastfeeding. Assessing IAH in early pregnancy could identify those at an increased risk of SH in the postpartum period.

Ambulatory Glucose Profile Changes During Pregnancy in Women With Type 1 Diabetes Using Intermittently Scanned Continuous Glucose Monitoring Empowered by Personalized Education

The ambulatory glucose profile is a valuable tool in managing type 1 diabetes during pregnancy. Time in range (TIR) in the third trimester is one of the most significant parameters contributing to good pregnancy outcomes. This study aimed to evaluate the effect of intermittently scanned continuous glucose monitoring (isCGM) empowered by education on glucose dynamics and to predict third trimester TIR. Data were retrospectively analyzed from 38 pregnant patients with type 1 diabetes (mean age 30.4 ± 6.4 years, BMI 23.7 ± 3.7 kg/m2, disease duration 15.4 ± 9.5 years, preconception A1C 6.9 ± 1%) who used a first-generation FreeStyle Libre isCGM system for at least 3 months before conception and had sensor data captured >70% of the time the system was used. Patients received personalized education on diabetes and on minimizing hypoglycemia and hyperglycemia using CGM trend arrows and frequent sensor scanning. This intervention improved glycemic parameters of glucose regulation (TIR, glucose management indicator, and mean glucose), hyperglycemia (time above range), glucose variability (SD and coefficient of variation [%CV]), and scanning frequency, but did not improve parameters of hypoglycemia (time below range and a number of low glucose events). Logistic regression analysis showed that the first trimester %CV and scanning frequency contributed to the third trimester TIR (P <0.01, adjusted R2 0.40). This study suggests that the use of isCGM empowered by personalized education improves glycemic control in pregnant women with type 1 diabetes. Scanning frequency and %CV in the first trimester predicts TIR in the third trimester, which could help clinicians intervene early to improve outcomes.

The ability of pGCD59 to predict adverse pregnancy outcomes: a prospective study of non-diabetic pregnant women in Ireland

AIM

Even though most pregnancies are uneventful, occasionally complications do occur. Gestational diabetes is linked to an increased risk of adverse pregnancy outcomes. Early identification of women at risk of experiencing adverse outcomes, ideally through a single blood test, would facilitate early intervention. Plasma glycated CD59 (pGCD59) is an emerging biomarker which has shown promise in identifying hyperglycaemia during pregnancy and has been associated with the risk of delivering an LGA infant. The aim of this study was to explore the ability of the first- and second-trimester pGCD59 to predict adverse pregnancy outcomes.

METHODS

This was a prospective study of 378 pregnant women. Samples for pGCD59 were taken at the first antenatal visit and at the time of the 2 h 75 g OGTT (24-28 weeks of gestation). Adjusted receiver operating characteristic curves were used to evaluate the ability of pGCD59 to predict maternal and neonatal outcomes.

RESULTS

First-trimester pGCD59 levels were higher in women with gestational diabetes who delivered a macrosomic infant (4.2 ± 0.7 vs. 3.5 ± 1.0 SPU, p < 0.01) or an LGA infant (4.3 ± 0.3 vs. 3.6 ± 1.0 SPU, p = 0.01) compared to women with GDM that did not experience these outcomes. Second-trimester pGCD59 levels were higher in women that developed polyhydramnios (2.9 ± 0.4 vs. 2.5 ± 1.1 SPU, p = 0.03). First- and second-trimester pGCD59 predicted pregnancy-induced hypertension with good accuracy (AUC:0.85, 95%CI:0.78-0.91; AUC: 0.80, 95%CI: 0.73-0.88, respectively) and neonatal hypoglycaemia with fair to good accuracy (AUC:0.77, 95%CI: 0.54-0.99, AUC:0.81, 95%CI:0.62-0.99).

CONCLUSIONS

This study has shown that pGCD59 has the potential to predict adverse pregnancy outcomes. Prospective studies with a larger number of cases are necessary to fully explore and validate the potential of this emerging biomarker in predicting adverse pregnancy outcomes.

Applications of continuous glucose monitoring across settings and populations: Report from the 23rd Hong Kong diabetes and cardiovascular risk factors-East meets west symposium

Continuous glucose monitoring (CGM) is now an integral part of glycaemic management in people with type 1 diabetes and those with insulin-treated type 2 diabetes. Immediate access to information on CGM glucose levels and trends helps to inform food choices, titration and timing of insulin doses and prompts corrective actions in the event of impending hypo- or hyperglycaemia. Although glycated haemoglobin (HbA1c) remains an important measure of the average of glucose, CGM metrics including time-in-range (TIR) and other metrics on glycaemic variability and hypoglycaemia are strongly endorsed by people with diabetes as impacting their daily lives. There is growing consensus on definitions and targets of CGM metrics with an increasing number of studies demonstrating correlations between CGM metrics and incident complications of diabetes. Implementation of new technologies needs to take into consideration factors such as cost-effectiveness, accessibility as well as acceptability of the person with diabetes and healthcare professional. The United Kingdom is one of the few countries that have developed clinical pathways for integrating CGM into the routine care of people with type 1 diabetes. Besides type 1 diabetes, special groups such as people with impaired kidney function and women during pregnancy may derive additional benefits from CGM.

Observational assessments of the relationship of dietary and pharmacological treatment on continuous measures of dysglycemia over 24 hours in women with gestational diabetes

OBJECTIVES

Studies that use continuous glucose monitoring (CGM) to monitor women with gestational diabetes (GDM), highlight the importance of managing dysglycemia over a 24-hour period. However, the effect of current treatment methods on dysglycemia over 24-hrs are currently unknown. This study aimed to characterise CGM metrics over 24-hrs in women with GDM and the moderating effect of treatment strategy.

METHODS

Retrospective analysis of CGM data from 128 women with GDM in antenatal diabetes clinics. CGM was measured for 7-days between 30-32 weeks gestation. Non-parametric tests were used to evaluate differences of CGM between periods of day (morning, afternoon, evening, and overnight) and between treatment methods (i.e., diet alone or diet+metformin). Exploratory analysis in a subgroup of 34 of participants was performed to investigate the association between self-reported macronutrient intake and glycaemic control.

RESULTS

Glucose levels significantly differed during the day (i.e., morning to evening; P<0.001) and were significantly higher (i.e., mean blood glucose and area under the curve [AUC]) and more variable (i.e., SD and CV) than overnight glucose levels. Morning showed the highest amount of variability (CV; 8.4% vs 6.5%, P<0.001 and SD; 0.49 mmol/L vs 0.38 mmol/L, P<0.001). When comparing treatment methods, mean glucose (6.09 vs 5.65 mmol/L; P<0.001) and AUC (8760.8 vs 8115.1 mmol/L.hr; P<0.001) were significantly higher in diet+metformin compared to diet alone. Finally, the exploratory analysis revealed a favourable association between higher protein intake (+1SD or +92 kcal/day) and lower mean glucose (-0.91 mmol/L p, P=0.02) and total AUC (1209.6 mmol/L.h, P=0.021).

CONCLUSIONS

Glycemia varies considerably across a day, with morning glycemia demonstrating greatest variability. Additionally, our work supports that individuals assigned to diet+metformin have greater difficulty managing glycemia and results suggest that increased dietary protein may assist with management of dysglycemia. Future work is needed to investigate the benefit of increased protein intake on management of dysglycemia.

The Role of Early Pregnancy Maternal pGCD59 Levels in Predicting Neonatal Hypoglycemia-Subanalysis of the DALI Study

CONTEXT

Neonatal hypoglycaemia (NH) is the most common metabolic problem in infants born of mothers with gestational diabetes. Plasma glycated CD59 (pGCD59) is an emerging biomarker that has shown potential in identifying women at risk of developing gestational diabetes. The aim of this study was to assess the association between early maternal levels of pGCD59 and NH.

OBJECTIVE

The aim of this study was to assess the association between early pregnancy maternal levels of plasma glycated CD59 (pGCD59) and neonatal hypoglycemia (NH).

METHODS

This is an observational study of pregnant women with a prepregnancy body mass index (BMI) greater than or equal to 29 screened for eligibility to participate in the Vitamin D and Lifestyle Intervention for Gestational Diabetes (DALI) trial. This analysis included 399 pregnancies. Levels of pGCD59 were measured in fasting maternal samples taken at the time of a 75-g, 2-hour oral glucose tolerance test performed in early pregnancy (< 20 weeks). NH, the study outcome, was defined as a heel-prick capillary glucose level of less than 2.6 mmol/L within 48 hours of delivery.

RESULTS

We identified 30 infants with NH. Maternal levels of pGCD59 in early pregnancy were positively associated with the prevalence of NH (one-way analysis of variance, P < .001). The odds of NH were higher in infants from mothers in tertile 3 of pGCD59 levels compared to those from mothers in tertile 1 (odds ratio [OR]: 2.41; 95% CI, 1.03-5.63). However, this was attenuated when adjusted for maternal BMI (OR: 2.28; 95% CI, 0.96-5.43). The cross-validated area under the curve (AUC) was 0.64 (95% CI, 0.54-0.74), and adjusted for maternal BMI, age, and ethnicity, the AUC was 0.70 (95% CI, 0.56-0.78).

CONCLUSION

Although pGCD59 levels in early pregnancy in women with BMI greater than or equal to 29 are associated with NH, our results indicate that this biomarker by itself is only a fair predictor of NH.

Epidemiology and Therapeutic Strategies for Women With Preexisting Diabetes in Pregnancy: How Far Have We Come? The 2021 Norbert Freinkel Award Lecture

The field of diabetes in pregnancy has witnessed tremendous changes over the past 30 years, with an explosive growth in case numbers along with new and exciting opportunities to affect outcomes. Type 1 diabetes in pregnancy has increased by 40%, but type 2 diabetes in pregnancy, rarely seen 30 years ago, has more than doubled and, in some cases, tripled in prevalence. Compared with women with type 2 diabetes, women with type 1 diabetes have higher HbA1c, more large-for-gestational-age infants, and more preterm births. Women with type 2 diabetes have more chronic hypertension, more socioeconomic deprivation, and higher rates of perinatal mortality. Large randomized trials in women with diabetes in pregnancy have helped us understand the effectiveness of new technologies (i.e., continuous glucose monitoring) in women with type 1 diabetes, and the addition of metformin to insulin in women with type 2 diabetes, in improving pregnancy outcomes. Future endeavors, including artificial pancreas systems in women with type 1 diabetes and the use of continuous glucose monitoring, a better understanding of nutrition during pregnancy, and approaches to improve preconception and pregnancy self-care in women with type 2 diabetes, may lead to further improved outcomes.

Addition of intermittently scanned continuous glucose monitoring to standard care in a cohort of pregnant women with type 1 diabetes: effect on glycaemic control and pregnancy outcomes

AIMS/HYPOTHESIS

The aim of this study was to assess whether the addition of intermittently scanned continuous glucose monitoring (isCGM) to standard care (self-monitoring of blood glucose [SMBG] alone) improves glycaemic control and pregnancy outcomes in women with type 1 diabetes and multiple daily injections.

METHODS

This was a multicentre observational cohort study of 300 pregnant women with type 1 diabetes in Spain, including 168 women using SMBG (standard care) and 132 women using isCGM in addition to standard care. In addition to HbA1c, the time in range (TIR), time below range (TBR) and time above range (TAR) with regard to the pregnancy glucose target range (3.5-7.8 mmol/l) were also evaluated in women using isCGM. Logistic regression models were performed for adverse pregnancy outcomes adjusted for baseline maternal characteristics and centre.

RESULTS

The isCGM group had a lower median HbA1c in the second trimester than the SMBG group (41.0 [IQR 35.5-46.4] vs 43.2 [IQR 37.7-47.5] mmol/mol, 5.9% [IQR 5.4-6.4%] vs 6.1% [IQR 5.6-6.5%]; p=0.034), with no differences between the groups in the other trimesters (SMBG vs isCGM: first trimester 47.5 [IQR 42.1-54.1] vs 45.9 [IQR 39.9-51.9] mmol/mol, 6.5% [IQR 6.0-7.1%] vs 6.4% [IQR 5.8-6.9%]; third trimester 43.2 [IQR 39.9-47.5] vs 43.2 [IQR 39.9-47.5] mmol/mol, 6.1% [IQR 5.8-6.5%] vs 6.1% [IQR 5.7-6.5%]). The whole cohort showed a slight increase in HbA1c from the second to the third trimester, with a significantly higher rise in the isCGM group than in the SMBG group (median difference 2.2 vs 1.1 mmol/mol [0.2% vs 0.1%]; p=0.033). Regarding neonatal outcomes, newborns of women using isCGM were more likely to have neonatal hypoglycaemia than newborns of non-sensor users (27.4% vs 19.1%; ORadjusted 2.20 [95% CI 1.14, 4.30]), whereas there were no differences between the groups in large-for-gestational-age (LGA) infants (40.6% vs 45.1%; ORadjusted 0.73 [95% CI 0.42, 1.25]), Caesarean section (57.6% vs 48.8%; ORadjusted 1.33 [95% CI 0.78, 2.27]) or prematurity (27.3% vs 24.8%; ORadjusted 1.05 [95% CI 0.55, 1.99]) in the adjusted models. A sensitivity analysis in pregnancies without LGA infants or prematurity also showed that the use of isCGM was associated with a higher risk of neonatal hypoglycaemia (non-LGA: ORadjusted 2.63 [95% CI 1.01, 6.91]; non-prematurity: ORadjusted 2.52 [95% CI 1.12, 5.67]). For isCGM users, the risk of delivering an LGA infant was associated with TIR, TAR and TBR in the second trimester in the logistic regression analysis.

CONCLUSIONS/INTERPRETATION

isCGM use provided an initial improvement in glycaemic control that was not sustained. Furthermore, offspring of isCGM users were more likely to have neonatal hypoglycaemia, with similar rates of macrosomia and prematurity to those of women receiving standard care.

The utility of first trimester plasma glycated CD59 (pGCD59) in predicting gestational diabetes mellitus: A prospective study of non-diabetic pregnant women in Ireland

AIMS

To evaluate the ability of first trimester plasma glycated CD59 (pGCD59) to predict gestational diabetes mellitus (GDM) at 24-28 weeks of gestation.

METHODS

Prospectively, in 378 pregnant women, GDM was diagnosed using the one step 2 h 75 g oral glucose tolerance test adjudicated by the World Health Organisation (WHO) 2013 criteria. The ability of pGCD59 to predict GDM was assessed using receiver operating characteristic (ROC) curves adjusted for maternal age, body mass index (BMI), maternal ethnicity, parity, previous GDM, family history of diabetes mellitus and week of gestation at time of pGCD59 sampling.

RESULTS

pGCD59 generated an adjusted area under the curve (AUC) of (a) 0.63 (95 %CI:0.56-0.70, p < 0.001) for predicting GDM, and (b) 0.71 (95 %CI:0.62-0.79, p < 0.001 for GDM diagnosed with a fasting plasma glucose (FPG) ≥ 5.1 mmol/L. Sensitivity analysis of BMI subgroups showed that pGCD59 generated the highest AUC in the 35 kg/m² ≤ BMI < 40 kg/m² (AUC:0.85, 95 %CI:0.70-0.98) and BMI ≥ 40 kg/m² (AUC:0.88, 95 %CI:0.63-0.99) categories.

CONCLUSIONS

Early in pregnancy, pGCD59 may be a good predictor of GDM in women with a high BMI and a fair predictor of GDM diagnosed by an elevated FPG independent of BMI.

Continuous Glucose Monitoring Metrics and Birth Weight: Informing Management of Type 1 Diabetes Throughout Pregnancy

OBJECTIVE

To determine gestational weekly changes in continuous glucose monitoring (CGM) metrics and 24-h glucose profiles and their relationship to infant birth weight in pregnant women with type 1 diabetes.

RESEARCH DESIGN AND METHODS

An analysis of >10.5 million CGM glucose measures from 386 pregnant women with type 1 diabetes from two international multicenter studies was performed. CGM glucose metrics and 24-h glucose profiles were calculated for each gestational week, and the relationship to normal (10-90th percentile) and large (>90th percentile) for gestational age (LGA) birth weight infants was determined.

RESULTS

Mean CGM glucose concentration fell and percentage of time spent in the pregnancy target range of 3.5-7.8 mmol/L (63-140 mg/dL) increased in the first 10 weeks of pregnancy and plateaued until 28 weeks of gestation, before further improvement in mean glucose and percentage of time in range until delivery. Maternal CGM glucose metrics diverged at 10 weeks of gestation, with significantly lower mean CGM glucose concentration (7.1 mmol/L; 95% CI 7.05-7.15 [127.8 mg/dL; 95% CI 126.9-128.7] vs. 7.5 mmol/L; 95% CI 7.45-7.55 [135 mg/dL; 95% CI 134.1-135.9]) and higher percentage of time in range (55%; 95% CI 54-56 vs. 50%; 95% CI 49-51) in women who had normal versus LGA. The 24-h glucose profiles were significantly higher across the day from 10 weeks of gestation in LGA.

CONCLUSIONS

Normal birth weight is associated with achieving significantly lower mean CGM glucose concentration across the 24-h day and higher CGM time in range from before the end of the first trimester, emphasizing the need for a shift in clinical management, with increased focus on using weekly CGM glucose targets for optimizing maternal glycemia from early pregnancy.

Novel Continuous Glucose Monitoring Metrics and Large-for-Gestational-Age Risk: An Exploratory Retrospective Cohort Study in Pregnancies with Type 1 Diabetes

Background: Continuous glucose monitoring (CGM) improves pregnancy outcomes in patients with type 1 diabetes (T1D). We aimed to assess the between-group differences in glycated hemoglobin (HbA1c) and the incidence of large-for-gestational-age (LGA) neonates in CGM and glucometer users and analyze the potential association of novel CGM metrics with LGA risk in T1D pregnancies. Materials and Methods: Our retrospective study cohort included 134 women with T1D treated with insulin pumps-75 of them used CGM and 59 patients measured their glucose concentrations using glucometers only. As part of our study, we matched the CGM users and patients who preferred the self-monitoring of blood glucose (SMBG) according to their baseline HbA1c and White's diabetes class at a 1:1 ratio. After the matching, both groups included 42 pregnancies. Results: We did not find any difference in changes in HbA1c and perinatal outcomes between CGM and SMBG users; however, we achieved a limited statistical power, and there were more cases of diabetic nephropathy in the SMBG group. Mothers of LGA infants had higher first-trimester HbA1c, time above target, and mean glucose concentrations in each trimester of pregnancy. Other CGM metrics reflecting glucose fluctuations attributed to hyperglycemia were associated with an increased risk of LGA. Despite optimal maternal HbA1c, 39% of neonates demonstrated LGA. Conclusions: Although participants reached the target HbA1c concentrations, mothers of LGA newborns had higher first-trimester HbA1c, as well as higher time above target range, higher mean glucose concentrations, and more glycemic fluctuations, suggesting that several CGM metrics associated with maternal hyperglycemia are associated with LGA in pregnancies with T1D.

Continuous Glucose Monitoring Time-in-Range and HbA1c Targets in Pregnant Women with Type 1 Diabetes

The CONCEPTT trial compared real-time Continuous Glucose Monitoring (RT-CGM) to capillary glucose monitoring in pregnant women with type 1 diabetes. We analyzed CGM and glycated hemoglobin (HbA_1c) measures in first (n = 221), second (n = 197), and third (n = 172) trimesters, aiming to examine target glucose attainment and associations with pregnancy outcomes. CGM targets were Time-in-range (TIR) > 70%, Time-above-range (TAR) <25%, and Time-below-range (TBR) < 4%, and HbA_1c targets < 6.5% (National Institute for Health and Care Excellence [NICE]) and HbA_1c < 6.0% in second and third trimesters (American Diabetes Association [ADA]). TIR/TAR/TBR targets were achieved by 7.7/14.5/30.3% participants in first, 10.2/14.2/52.8% in second, and 35.5/37.2/52.9% in third trimesters. CGM target attainment was low but increased during pregnancy and with RT-CGM use. In the adjusted analyses, achieving TBR target was associated with a higher risk of pre-eclampsia and neonatal hypoglycemia. ADA HbA_1c target attainment was low and unchanged during pregnancy (23.5/27.9/23.8%) but increased with RT-CGM use. In the adjusted analyses, HbA_1c target attainment was associated with a lower risk of preterm birth, large-for-gestational age and neonatal hypoglycemia. We conclude that CONCEPTT trial participants had a low rate of CGM and of HbA_1c target attainment. Attainment of CGM and NICE HbA_1c targets increased throughout gestation and all targets (both NICE/ADA HbA_1c and CGM) were more likely to be achieved by RT-CGM users, at 34 weeks' gestation. ADA HbA_1c target achievement was independently associated with better perinatal outcomes, while the independent association of TBR target achievement with increased risk warrants further study. ClinicalTrials.gov Registration Identifier NCT01788527.

Monitoring motherhood: Monitoring and optimizing glycaemia in women with pre-existing diabetes in pregnancy

Despite recent advances in care, women with diabetes in pregnancy are still at increased risk of multiple pregnancy complications. Offspring exposed to hyperglycaemia in utero also experience long-term health sequelae, affecting neurocognitive and cardiometabolic status. Many of these adverse consequences can be prevented or ameliorated with good medical care, specifically to optimize glycaemic control. The accurate assessment of glycaemia in pregnancy is therefore vital to safeguard the health of mother and child. However, there is no consensus about the best method of monitoring glycaemic control in pregnancy. Short-term changes in insulin dosage and lifestyle, with altered appetite, insulin sensitivity and red cell turnover create difficulties in interpretation of standard laboratory measures such as HbA_1c. The ideal marker would provide short-term feedback on daily or weekly glycaemic control, with additional capability to predict pregnancies at high risk of suboptimal outcomes. Several novel biochemical markers are available which allow assessment of dynamic changes in glycaemia over weeks rather than months. Continuous glucose monitoring devices have advanced in accuracy and provide new opportunities for robust assessment of glycaemia in pregnancy. Recent work from the continuous glucose monitoring in pregnant women with type 1 diabetes trial (CONCEPTT) has provided information about the ability of different markers of glycaemia to predict pregnancy outcomes.The aim of this review is to summarize the care for women with pre-existing diabetes in pregnancy and to highlight the important role of glycaemic monitoring in pregnancy.

Preliminary reference intervals of Glycated Albumin in healthy Caucasian pregnant women

BACKGROUND AND AIMS

Glycated albumin (GA) could represent a useful biomarker in pregnant women for diagnosing and monitoring gestational diabetes mellitus (GDM). The establishment of reference intervals (RI) is mandatory before assessing its clinical usefulness. The RIs of GA in healthy pregnant women are not well defined. The aim of the current study was to establish the RI in a cohort consisting of Caucasian pregnant women without overt diabetes mellitus or gestational diabetes mellitus.

METHODS

The study included 183 healthy pregnant women. GA was measured on plasma by an enzymatic method (quantILab Glycated Albumin, IL Werfen, Germany). The RI was calculated by the non-parametric and robust methods.

RESULTS

The RI of GA in the whole population was 10.16% (90%CI 9.60-10.70) and 15.44% (90%CI 14.90-16.90). GA levels decreased during pregnancy, with lower levels in the third trimester: 10.11 (90%CI 9.48-10.79) and 15.72 (90%CI 15.15-16.27) in the first trimester, 10.49 (90%CI 10.05-10.96) and 15.49 (90%CI 15.05-15.92) in the second trimester, 9.84 (90%CI 9.50-10.22) and 14.57 (90%CI 14.11-15.01) in the third trimester. Finally, a weak negative correlation was found between GA levels and body mass index.

CONCLUSION

This is the first study establishing the RIs of GA in Caucasian healthy pregnant women.