Analysis of Continuous Glucose Monitoring in Pregnant Women With Diabetes: Distinct Temporal Patterns of Glucose Associated With Large-for-Gestational-Age Infants

Practical Approach to Continuous Glucose Monitoring (CGM) Interpretation and Automated Insulin Delivery (AID) Use in Pregnancy: Considerations for Obstetric Providers

While automated insulin delivery (AID) systems have multiple well-established benefits outside of pregnancy and are widely used in non-pregnant individuals with type 1 diabetes (T1D), none of the commercially available AID systems in North America are approved for use during pregnancy. Use of commercially available AID systems off-label in pregnancy is currently limited by: (1) glucose targets higher than the fasting glucose target range recommended during pregnancy and (2) algorithms which were not designed for the dynamic changes in insulin resistance which occur across gestation. However, as AID use in the general population expands, many individuals will opt to continue using these systems off-label during pregnancy, and thus, guidance for providers regarding AID use and optimization during pregnancy is of the utmost importance. A cornerstone to the effective use of AID systems is the systematic and accurate interpretation of continuous glucose monitoring (CGM) data. One obstacle to the use of both CGM and AID systems by obstetric providers is the lack of comfort with CGM interpretation. We therefore present here: (1) a systematic approach to CGM interpretation during pregnancy and (2) practical guidance regarding AID use during pregnancy for individuals who opt to use commercially available AID systems off-label during pregnancy after consideration of individualized risks and benefits.

Analysis glycemic variability in pregnant women with various type of hyperglycemia

OBJECTIVE

The study primarily aims to compare alterations in the daily patterns of glucose fluctuations across individuals with different kinds of diabetes in pregnancy and secondly investigate influencing factors that may react with glucose variations.

METHODS

We conducted a retrospective cohort study of 776 pregnant women in Shanghai General Hospital. We grouped participants who were exposed to gestational hyperglycemia into 5 sub-groups [Type 1 diabetes (T1DM), Type 2 diabetes (T2DM), Overt diabetes, Gestational diabetes (GDMA1 and GDMA2). Demographic variables and GV parameters were compared among 5 groups through ANOVA-test and Chi-square test. We estimated odd ratios (ORs) for the association between glucose coefficient of variation (CV) and possible influencing variables.

RESULTS

A final total of 776 pregnant women were analyzed. The proportion of pregnant women with pre-gestational diabetes was 31.83% (T1DM: 3.35%,T2DM: 28.48%), ODM 26.68%, and GDM was 41.49% (GDMA1:18.04%, GDMA2: 23.45%). T1DM group performed greatest glucose fluctuations with a CV value 35.02% whereas the number in all the other groups was no more than 22.82% (ODM group). In terms of achieving glycemic control target, only 57.70% participants hit the goal while all the other groups achieved the standard with at least a percentage of 94.20% (ODM group). Other parameters (GMI < 6.0%, GA < 15.70% and HbA1c < 6.0%) showed similar trends in each group. On multivariate logistic regression analysis of possible factors influencing CV, only body mass index (BMI) (OR: 0.754, 95% CI: 0.585-0.971; P = 0.029), HOMA- β (OR:0.969, 95%CI: 0.959-0.976; P = 0.037) and fasting plasma glucose (FPG) (OR: 1.832, 95% CI: 1.170-2.870; P = 0.008) reached statistical significance.

CONCLUSIONS

Pregnant women with type 1 or type 2 diabetes exhibit significantly greater glycemic variability compared to those with gestational diabetes, with the ODM group showing intermediate variability, and BMI, HOMA-β, and FPG identified as independent risk factors for unstable glucose variability.

Glucose time in range trajectories during pregnancy and association with adverse perinatal outcomes: a joint latent-class trajectory modeling approach

BACKGROUND

While time in range (TIR) summarized over pregnancy is associated with adverse outcomes among individuals with preexisting type 1 or 2 diabetes, the impact of TIR trajectories with advancing gestation is unknown.

OBJECTIVE

To identify glucose TIR trajectories across pregnancy and evaluate their association with perinatal outcomes among patients with preexisting diabetes.

STUDY DESIGN

Retrospective, single-center cohort study of pregnant patients with type 1 or 2 diabetes who used continuous glucose monitoring (CGM) and delivered in 2019 to 2023. Weekly TIR (65-140 mg/dL) was computed starting at 10 weeks' gestation, and joint latent-class trajectory modeling identified discrete TIR trajectory groups. Patients were classified into groups, and multivariable logistic regression estimated the associations between groups and perinatal outcomes.

RESULTS

Of 179 pregnant patients, 91 had type 1 and 88 had type 2 diabetes. We identified four TIR trajectory groups using data from over 5.1 million CGM measurements: (1) good control, stable (n=48), (2) moderate control, initial improvement, and late decline (n=22), (3) moderate control, late improvement (n=63), and (4) poor control, initial worsening and late improvement (n=46). All perinatal outcomes differed by TIR trajectory. Groups 2, 3, and 4 with suboptimal control in early pregnancy were associated with higher odds of preterm birth, indicated preterm birth, and NICU admission, compared to group 1. Groups 3 and 4, which had the lowest TIR during second and early third trimesters, were associated with higher odds of large-for-gestational-age (LGA). Only group 4 was associated with higher odds of preeclampsia and neonatal hypoglycemia.

CONCLUSION

Achieving glycemic control in the second and early third trimesters during fetal and placental growth and development is important to reduce the risk of adverse pregnancy outcomes, particularly LGA. Third-trimester TIR decline may impact risk of preterm birth and NICU admission.

Exploring the relationship between maternal Continuous Glucose Monitoring "time in range" and fetal abdominal circumference in pregnant women with Type 1 Diabetes

BACKGROUND

To explore the relationship between maternal glycaemic control and fetal abdominal circumference in pregnancies complicated by T1D.

METHODS

This is a retrospective cohort study of 81 pregnant women with T1D using CGM. Inclusion criteria were T1D, CGM use, ≥2 in-house ultrasounds, and the birth of a live singleton neonate between 1st December 2019 and 1st December 2022. Linear regression analysis was used to assess the cross-sectional relationships between estimated fetal abdominal circumference (AC) on ultrasound and time in range (TIR) at matched time-points in the third trimester of pregnancy. Linear regression analysis was also used to examine whether first trimester TIR and HbA1c predicts third trimester fetal AC.

RESULTS

At baseline, the mean ± standard deviation (SD) of the first trimester HbA1c was 7.0 ± 1.4% and mean ± SD total daily dose (TDD) insulin was 46.6 ± 21.0 units. The mean ± SD birthweight was 3367.0 ± 861.3 grams. There was no cross-sectional relationship between TIR and fetal AC at 28-, 32- or 36-week' gestation. The results of the regression analysis indicate a significant relationship between first trimester TIR (independent predictor) and fetal AC (dependent variable) at 32- and 36-weeks' gestation while controlling for maternal age, BMI, pump use, and TDD insulin (Adjβ= -0.42, 95%CI -0.80 to -0.03 and Adjβ = -0.57, 95%CI -1.02 to -0.12 at 32- and 36-weeks respectively). Although there was a significant relationship between first trimester HbA1c and fetal AC at 32-weeks' gestation (β = 3.81, 95%CI 0.29 to 7.33), the relationship was not significant after adjustment for confounders.

CONCLUSIONS

There was no cross-sectional relationship between TIR and fetal AC in the third trimester of pregnancy but first trimester TIR did predict fetal AC in late pregnancy.

Postnatal levels of glycated albumin and glycated hemoglobin A1c in mothers of large-for-gestational-age newborns

Background

Gestational diabetes mellitus (GDM) is an important cause of macrosomia. The value of glycated albumin (GlyA) has been demonstrated to be a useful marker of glycemic control in pregnancy and a predictor of adverse perinatal outcomes. The aim of this study was to investigate the relationship between the postnatal levels of GlyA and glycated hemoglobin A1c (HbA1c) regarding the prenatal diagnosis of GDM in mothers of large-for-gestational-age (LGA) newborns.

Methods

The study included mothers and their LGA newborns born between July 2017 and September 2019. The mothers were grouped according to the prenatal diagnosis of GDM, and measurements of GlyA and HbA1c levels in their serum were performed on the first day after delivery of a LGA newborn.

Results

A total of 61 LGA newborns and their mothers were enrolled in the study. The median GlyA level was higher, at 16.4% (81.0 µmol/L), whereas the HbA1c level was lower in the group without a prenatal diagnosis of GDM; the differences between groups regarding the GlyA and HbA1c levels were not significant (p > 0.05). The postnatal level of maternal GlyA was positively correlated with birth weight (β = 0.022, p = 0.007), but no correlation with the presence of other adverse perinatal outcomes was found.

Conclusion

Mothers of LGA newborns who were not diagnosed with GDM during pregnancy had higher median levels of GlyA and lower HbA1c levels than mothers with prenatal diagnosis of GDM. Values of GlyA in mothers were positively correlated with the birth weight of their newborns but no correlation with other adverse perinatal outcomes was found. Our results indicate the potential value of GlyA for screening of GDM in the last trimester of pregnancy.

Continuous Glucose Monitoring-Derived Differences in Pregnancies With and Without Adverse Perinatal Outcomes

OBJECTIVE

To evaluate whether continuous glucose monitoring (CGM)-derived glycemic patterns observed throughout pregnancy were associated with adverse perinatal outcomes, specifically fetal growth disorders and hypertensive disorders of pregnancy (HDP).

METHODS

We conducted a prospective observational study of individuals with viable singleton pregnancies and screening hemoglobin A 1c levels less than 6.5%. Those with preexisting diabetes were excluded. Enrollment occurred at the earliest gestational age before 17 weeks. Participants wore blinded continuous glucose monitors consecutively as willing until delivery. Those with at least 14 days of CGM data were included in analysis. Rates of large-for-gestational-age (LGA) neonates, small-for-gestational age (SGA) neonates, and HDP were assessed. Continuous glucose monitoring-derived glycemic metrics were calculated, including mean glucose level and percent time above and below thresholds. Two-sample t tests were used to compare glycemic metrics between participants with and without adverse perinatal outcomes.

RESULTS

Of 937 participants enrolled, 760 met inclusion criteria. Those delivering LGA neonates or who were diagnosed with HDP had higher mean glucose levels (102±9 vs 100±8, P =.01 and 103±8 vs 99±8, P <.001) and spent more time above 120 mg/dL (median 16% vs 12%, P =.006, and 16% vs 12%, P <.001, respectively) and above 140 mg/dL (median 3.9% vs 2.8%, P =.006, and 3.5% vs 2.8%, P <.001, respectively) throughout gestation than those without these outcomes. These findings were present regardless of gestational diabetes mellitus status. Participants with SGA neonates had lower mean glucose levels (97±7 vs 101±8, P =.01) and spent less time above 140 mg/dL (median 1.6% vs 2.3%, P =.01) and more time below 63 mg/dL (median 3.0% vs 2.3%, P =.02) than those without SGA neonates.

CONCLUSION

Individuals with LGA neonates or HDP exhibit a slightly higher mean glucose levels and spend more time hyperglycemic in early pregnancy than those who do not experience these outcomes.

An automated insulin delivery system from pregestational care to postpartum in women with type 1 diabetes. Preliminary experience with telemedicine in 6 patients

INTRODUCTION

The use of most commercially available automated insulin delivery (AID) systems is off-label in pregnancy. However, an increasing number of women with type 1 diabetes (T1D) use such devices throughout pregnancy and delivery. We analysed the data of six women with T1D from a single centre (Diabetology Outpatient Clinic of District-63/Asl Salerno, Italy) who were able to start and maintain AID therapy with the MiniMed™ 780G (Medtronic, Minneapolis, MN, USA) throughout the pregestational care period, pregnancy, delivery, and postpartum.

METHODS

We retrospectively collected data from six patients with T1D who received training and initiation on use of the MiniMed™ 780G and attended follow-up visits throughout pregnancy (these visits were virtual because of the COVID-19 pandemic). All patients maintained their devices in the closed-loop setting throughout pregnancy and during labour and delivery. We analysed data from the pregestational phase to the first 30 days postpartum.

RESULTS

All patients achieved the recommended metabolic goals before conception [median time in range (TIR) of 88% for 70-180 mg/dL; median pregnancy-specific TIR 63-140 mg/dL (ps-TIR) of 66% and maintained the ps-TIR until delivery (median ps-TIR 83%). All patients had slightly better metrics during the night than during the day, with a very low time below range of < 63 mg/dL. Optimal glycaemic values were also maintained on the day of labour and delivery (median ps-TIR 92.5%) and in the first 30 days postpartum, with no severe hypoglycaemia. The only neonatal complications were jaundice in one child and an interatrial defect in another child.

CONCLUSION

In our well-selected and trained patients, use of the MiniMed™ 780G helped to achieve and maintain ps-metrics from the pregestational period to delivery despite the fact that the algorithm is not set to achieve the ambitious glycaemic values recommended for pregnancy.

Randomized Trial of Assisted Hybrid Closed-Loop Therapy Versus Sensor-Augmented Pump Therapy in Pregnancy

Objective: Examine gestational safety, glycemic and health outcomes, of a hybrid closed-loop (HCL) system without pregnancy-specific glucose targets. Research Design: This was a pilot feasibility investigator-initiated, two-site, single-blind, randomized controlled trial of sensor-augmented pump therapy (SAPT) versus HCL therapy in type 1 diabetes pregnancies. Participants were enrolled in the first trimester and randomized at 14-18 weeks of gestation and used SAPT or HCL until 4-6 weeks postpartum. We compared continuous glucose monitoring (CGM) metrics, severe hypoglycemia (SH), diabetic ketoacidosis (DKA), adverse skin reactions, and pregnancy outcomes between groups. Results: Baseline characteristics were similar between groups (n = 11 HCL and n = 12 SAPT). There was no SH or DKA episode after randomization. Time spent <54 mg/dL did not differ between groups. Time spent <63 mg/dL decreased in both groups, significantly in the HCL group (3.5% [1.3% standard error] second trimester and 2.8% [1.3%] third trimester vs. 7.9% [1.3%] run-in phase, P < 0.05 for both). Mean sensor glucose was lower with SAPT compared to HCL therapy in the third trimester (119 [4] mg/dL SAPT vs. 132 [4] mg/dL HCL, P < 0.05). Third trimester time-in-range (TIR; 63-140 mg/dL) increased with SAPT (68.2% [3.1%] vs. 64.3% [3.1%] run-in phase, P < 0.05). Gestational health outcomes did not differ between groups. The HCL group used assistive techniques, such as fake carbohydrate boluses and exiting HCL overnight. Conclusions: CGM within group differences were seen for time <63 mg/dL favoring HCL therapy and TIR favoring SAPT (third trimester vs. baseline). Safety and adverse pregnancy outcomes were similar between groups.

Real-World Evidence of Off-Label Use of Commercially Automated Insulin Delivery Systems Compared to Multiple Daily Insulin Injections in Pregnancies Complicated by Type 1 Diabetes

Aims: To compare glycemic control and maternal-fetal outcomes of women with type 1 diabetes (T1D) using hybrid closed loop (HCL) versus multiple daily insulin injections (MDI) plus continuous glucose monitoring. Methods: Multicenter prospective cohort study of pregnant women with T1D in Spain. We evaluated HbA1c and time spent within (TIR), below (TBR), and above (TAR) the pregnancy-specific glucose range of 3.5-7.8 mmol/L. Adjusted models were performed for adverse pregnancy outcomes, including baseline maternal characteristics and center. Results: One hundred twelve women were included (HCL n = 59). Women in the HCL group had a longer duration of diabetes and higher rates of prepregnancy care. There was no between-group difference in HbA1c in any trimester. However, in the second trimester, MDI users had a greater decrease in HbA1c (-6.12 ± 9.06 vs. -2.16 ± 7.42 mmol/mol, P = 0.031). No difference in TIR (3.5-7.8 mmol/L) and TAR was observed between HCL and MDI users, but with a higher total insulin dose in the second trimester [+0.13 IU/kg·day)]. HCL therapy was associated with increased maternal weight gain during pregnancy (βadjusted = 3.20 kg, 95% confidence interval [CI] 0.90-5.50). Regarding neonatal outcomes, newborns of HCL users were more likely to have higher birthweight (βadjusted = 279.0 g, 95% CI 39.5-518.5) and macrosomia (ORadjusted = 3.18, 95% CI 1.05-9.67) compared to MDI users. These associations disappeared when maternal weight gain or third trimester HbA1c was included in the models. Conclusions: In a real-world setting, HCL users gained more weight during pregnancy and had larger newborns than MDI users, while achieving similar glycemic control in terms of HbA1c and TIR.

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.

Discrete glucose profiles identified using continuous glucose monitoring data and their association with adverse pregnancy outcomes

BACKGROUND

Continuous glucose monitoring has facilitated the evaluation of dynamic changes in glucose throughout the day and their effect on fetal growth abnormalities in pregnancy. However, studies of multiple continuous glucose monitoring metrics combined and their association with other adverse pregnancy outcomes are limited.

OBJECTIVE

This study aimed to (1) use machine learning techniques to identify discrete glucose profiles based on weekly continuous glucose monitoring metrics in pregnant individuals with pregestational diabetes mellitus and (2) investigate their association with adverse pregnancy outcomes.

STUDY DESIGN

This study analyzed data from a retrospective cohort study of pregnant patients with type 1 or 2 diabetes mellitus who used Dexcom G6 continuous glucose monitoring and delivered a nonanomalous, singleton pregnancy at a tertiary center between 2019 and 2023. Continuous glucose monitoring data were collapsed into 39 weekly glycemic measures related to centrality, spread, excursions, and circadian cycle patterns. Principal component analysis and k-means clustering were used to identify 4 discrete groups, and patients were assigned to the group that best represented their continuous glucose monitoring patterns during pregnancy. Finally, the association between glucose profile groups and outcomes (preterm birth, cesarean delivery, preeclampsia, large-for-gestational-age neonate, neonatal hypoglycemia, and neonatal intensive care unit admission) was estimated using multivariate logistic regression adjusted for diabetes mellitus type, maternal age, insurance, continuous glucose monitoring use before pregnancy, and parity.

RESULTS

Of 177 included patients, 90 (50.8%) had type 1 diabetes mellitus, and 85 (48.3%) had type 2 diabetes mellitus. This study identified 4 glucose profiles: (1) well controlled; (2) suboptimally controlled with high variability, fasting hypoglycemia, and daytime hyperglycemia; (3) suboptimally controlled with minimal circadian variation; and (4) poorly controlled with peak hyperglycemia overnight. Compared with the well-controlled profile, the suboptimally controlled profile with high variability had higher odds of a large-for-gestational-age neonate (adjusted odds ratio, 3.34; 95% confidence interval, 1.15-9.89). The suboptimally controlled with minimal circadian variation profile had higher odds of preterm birth (adjusted odds ratio, 2.59; 95% confidence interval, 1.10-6.24), cesarean delivery (adjusted odds ratio, 2.76; 95% confidence interval, 1.09-7.46), and neonatal intensive care unit admission (adjusted odds ratio, 4.08; 95% confidence interval, 1.58-11.40). The poorly controlled profile with peak hyperglycemia overnight had higher odds of preeclampsia (adjusted odds ratio, 2.54; 95% confidence interval, 1.02-6.52), large-for-gestational-age neonate (adjusted odds ratio, 3.72; 95% confidence interval, 1.37-10.4), neonatal hypoglycemia (adjusted odds ratio, 3.53; 95% confidence interval, 1.37-9.71), and neonatal intensive care unit admission (adjusted odds ratio, 3.15; 95% confidence interval, 1.20-9.09).

CONCLUSION

Discrete glucose profiles of pregnant individuals with pregestational diabetes mellitus were identified through joint consideration of multiple continuous glucose monitoring metrics. Prolonged exposure to maternal hyperglycemia may be associated with a higher risk of adverse pregnancy outcomes than suboptimal glycemic control characterized by high glucose variability and intermittent hyperglycemia.

Continuous glucose monitoring in pregnant women with pregestational type 2 diabetes: a narrative review

Background: Type 2 diabetes (T2DM) in pregnancy is associated with poor perinatal outcomes; however, there are limited data on outcomes of continuous glucose monitoring (CGM) use in this population. Objective: We reviewed the literature on studies reporting CGM outcomes in pregnant women with T2DM. We aimed to synthesise in a narrative review, the effects of CGM on glycaemic and perinatal outcomes as well as current research gaps. Results: Of 34 articles screened, three reported CGM outcomes in T2DM pregnancies compared to self-monitoring of blood glucose (SMBG). Other feasibility and mixed population studies were also reviewed. CGM in T2DM has good feasibility, acceptability, and improved glycaemic control beyond SMBG. There were limited data to draw conclusions on its effect on maternal and fetal outcomes. Conclusion: Further studies of perinatal outcomes in pregnant women with T2DM are required to determine the impact of improved glycaemia with CGM.

Association between extrapolated time in range and large for gestational age infants in pregnant women with type 1 diabetes

AIMS

To evaluate the association between extrapolated time in range (eTIR), measured by self-monitoring of blood glucose (SMBG), and large-for-gestational-age (LGA) infants in pregnancies with type 1 diabetes (T1D).

METHODS

Retrospective cohort analysis including singleton pregnancies with T1D who started antenatal care before 20 gestational weeks and delivered live newborns at a Brazilian hospital between 2010 and 2019, with LGA fetuses as the main outcome. Glycemic records acquired using SMBG were categorized as eTIR, extrapolated time below range (eTBR), and extrapolated time above range (eTAR). Women were divided into two groups (LGA and adequate for gestational age [AGA]) and compared regarding clinical characteristics, obstetric outcomes, and frequencies of eTIR, eTBR, and eTAR. Logistic regression analysis verified the independent predictive variables for LGA infants.

RESULTS

Data from 125 pregnancies were analyzed. For the first, second and third trimesters, each 1 % increase in eTIR was associated with a decreased risk of LGA by 2.9 % (OR: 0.971; 95%CI: 0.945-0.998), 2.5 % (OR: 0.975; 95%CI: 0.951-0.999) and 2.3 % (OR: 0.977; 95%CI: 0.955-0.998) and each 1 % increase in eTAR was associated with an increased risk of LGA by 2.7 % (OR: 1.027; 95%CI: 1.005-1.050), 3.9 % (OR: 1.039; 95%CI: 1.014-1.063) and 4.6 % (OR: 1.046; 95%CI: 1.018-1.075), respectively.

CONCLUSION

The concept of TIR can be extrapolated to patients undergoing SMBG to assess the risk of LGA infants in pregnant women with T1D.

Continuous Glucose Monitoring and Time in Range: Association with Adverse Outcomes among People with Type 2 or Gestational Diabetes Mellitus

OBJECTIVE

Continuous glucose monitoring (CGM) has become available for women with type 2 diabetes mellitus (T2DM) or gestational diabetes mellitus (GDM) during pregnancy. The recommended time in range (TIR, blood glucose 70-140 mg/dL) and its correlation with adverse pregnancy outcomes in this group is unknown. Our aim was to compare maternal and neonatal outcomes in pregnant people with T2DM or GDM with average CGM TIR values >70 versus ≤70%.

STUDY DESIGN

We conducted a retrospective cohort study of all individuals using CGM during pregnancy from January 2017 to June 2022. Individuals with type 1 diabetes mellitus, or those missing CGM or delivery data were excluded. Primary composite neonatal outcome included any of the following: large for gestational age, NICU admission, need for intravenous glucose, respiratory support, or neonatal death. Secondary outcomes included other maternal and neonatal outcomes. Regression models were used to estimate adjusted odds ratio (aOR) and 95% confidence interval (CI).

RESULTS

During the study period, 141 individuals with diabetes utilized CGM during pregnancy, with 65 (46%) meeting inclusion criteria. Of the study population, 28 (43%) had TIR ≤70% and 37 (57%) had TIR > 70%. Compared with those with TIR > 70%, the primary composite outcome occurred more frequently in neonates of individuals TIR ≤70% (71.4 vs. 37.8%, aOR: 4.8, 95% CI: 1.6, 15.7). Furthermore, individuals with TIR ≤70% were more likely to have hypertensive disorders (42.9 vs. 16.2%, OR: 3.9, 95% CI: 1.3, 13.0), preterm delivery (54 vs. 27%, OR: 3.1, 95% CI: 1.1, 9.1): , and cesarean delivery (96.4 vs. 51.4%, OR: 4.6, 95% CI: 2.2, 15.1) compared with those with TIR >70%.

CONCLUSION

Among people with T2DM or GDM who utilized CGM during pregnancy, 4 out 10 individuals had TIR ≤70% and, compared with those with TIR > 70%, they had a higher likelihood of adverse neonatal and maternal outcomes.

KEY POINTS

· Time in range can be utilized as a metric for pregnant patients using continuous glucose monitor.. · Time in range >70% is achievable by 6 out of 10 patients.. · Time in range below goal is associated with adverse neonatal and maternal outcomes..

Continuous glucose monitoring metrics in pregnancy with type 1 diabetes mellitus

Managing diabetes during pregnancy is challenging, given the significant risk it poses for both maternal and foetal health outcomes. While traditional methods involve capillary self-monitoring of blood glucose level monitoring and periodic HbA1c tests, the advent of continuous glucose monitoring (CGM) systems has revolutionized the approach. These devices offer a safe and reliable means of tracking glucose levels in real-time, benefiting both women with diabetes during pregnancy and the healthcare providers. Moreover, CGM systems have shown a low rate of side effects and high feasibility when used in pregnancies complicated by diabetes, especially when paired with continuous subcutaneous insulin infusion pump as hybrid closed loop device. Such a combined approach has been demonstrated to improve overall blood sugar control, lessen the occurrence of preeclampsia and neonatal hypoglycaemia, and minimize the duration of neonatal intensive care unit stays. This paper aims to offer a comprehensive evaluation of CGM metrics specifically tailored for pregnancies impacted by type 1 diabetes mellitus.

Continuous Glucose Monitoring in Pregnancy

Diabetes mellitus in pregnancy is associated with adverse maternal and neonatal outcomes. Optimal glycemic control is associated with improved outcomes. Continuous glucose monitoring is a less invasive alternative to blood glucose measurements. Two types of continuous glucose monitoring are available in the market: real time and intermittently scanned. Continuous glucose monitoring is gaining popularity and is now recommended by some societies for glucose monitoring in pregnant women. In this review, we discuss the differences between the two types of continuous glucose monitoring, optimal treatment goals, and whether there is an improvement in maternal or neonatal outcomes.

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-derived glycemic metrics and adverse pregnancy outcomes among women with gestational diabetes: a prospective cohort study

Background

Continuous glucose monitoring (CGM) has shown potential in improving maternal and neonatal outcomes in individuals with type 1/2 diabetes, but data in gestational diabetes mellitus (GDM) is limited. We aimed to explore the relationship between CGM-derived metrics during pregnancy and pregnancy outcomes among women with GDM.

Methods

We recruited 1302 pregnant women with GDM at a mean gestational age of 26.0 weeks and followed them until delivery. Participants underwent a 14-day CGM measurement upon recruitment. The primary outcome was any adverse pregnancy outcome, defined as having at least one of the outcomes: preterm birth, large-for-gestational-age (LGA) birth, fetal distress, premature rupture of membranes, and neonatal intensive care unit (NICU) admission. The individual outcomes included in the primary outcome were considered as secondary outcomes. We conducted multivariable logistic regression to evaluate the association of CGM-derived metrics with these outcomes.

Findings

Per 1-SD difference in time above range (TAR), glucose area under the curve (AUC), nighttime mean blood glucose (MBG), daytime MBG, and daily MBG was associated with higher risk of any adverse pregnancy outcome, with odds ratio: 1.22 (95% CI 1.08-1.36), 1.22 (95% CI 1.09-1.37), 1.18 (95% CI 1.05-1.32), 1.21 (95% CI 1.07-1.35), and 1.22 (95% CI 1.09-1.37), respectively. Time in range, TAR, AUC, nighttime MBG, daytime MBG, daily MBG, and mean amplitude of glucose excursions were positively associated, while time blow range was inversely associated with the risk of LGA. Additionally, higher value for TAR was associated with higher risk of NICU admission. We further summarized the potential thresholds of TAR (2.5%) and daily MBG (4.8 mmol/L) to distinguish individuals with and without any adverse pregnancy outcome.

Interpretation

The CGM-derived metrics may help identify individuals at higher risk of adverse pregnancy outcomes. These CGM biomarkers could serve as potential new intervention targets to maintain a healthy pregnancy status among women with GDM.

Funding

National Key R&D Program of China, National Natural Science Foundation of China, and Westlake Laboratory of Life Sciences and Biomedicine.

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.

The role of technology in the care of diabetes mellitus in pregnancy: an expert review

Diabetes mellitus is one of the most commonly encountered pregnancy complications and is associated with multiple adverse perinatal outcomes. Technology has progressed to address the unique challenges patients face in managing diabetes mellitus in pregnancy. Technology has bolstered diabetes mellitus education with smartphone applications focused on nutrition counseling and carbohydrate intake advice. Continuous glucose monitors and insulin infusion systems have shown benefit by simplifying glycemic monitoring and insulin administration. Improvements in glycemic control and perinatal outcomes have been seen with continuous glucose monitor use when compared with intermittent blood glucose monitoring, and more pregnant people are using insulin pumps instead of multiple daily insulin injections. Hybrid closed-loop systems are emerging and are able to integrate continuous glucose monitoring and insulin pump technologies while maximizing automated features in the nonpregnant population, but these have not been endorsed for use in pregnancy yet. Applying telehealth practices has been associated with high patient satisfaction among those with diabetes mellitus in pregnancy, and leveraging remote patient monitoring through telehealth platforms and short-range wireless technologies can reduce the burden of patient visits. As technology becomes more integrated into routine management of diabetes mellitus in pregnancy, practitioners should emphasize individualized counseling and device selection to ensure patient autonomy and safety.

Insulin pump therapy with and without continuous glucose monitoring in pregnant women with type 1 diabetes: a prospective observational Orchestra Foundation study in Poland

AIMS

The effects of continuous subcutaneous insulin infusion (CSII) therapy with or without continuous glucose monitoring (CGM) on neonatal outcomes and glycemic outcomes of pregnant women with type 1 diabetes (T1D), living in Poland, were assessed.

METHODS

This prospective observational study enrolled women with T1D (N = 481, aged 18-45 years) who were pregnant or planned pregnancy. All used CSII therapy and a subset used CGM with CSII (CSII + CGM). Neonatal outcomes (e.g., rate of large for gestational age [LGA] delivery [birth weight > 90th percentile]) and maternal glycemia (e.g., HbA1c and percentage of time at sensor glucose ranges) were evaluated.

RESULTS

Overall HbA1c at trimesters 1, 2, and 3 was 6.8 ± 1.1% (50.9 ± 12.3 mmol/mol, N = 354), 5.8 ± 0.7% (40.1 ± 8.0 mmol/mol, N = 318), and 5.9 ± 0.7% (41.4 ± 8.0 mmol/mol, N = 255), respectively. A HbA1c target of < 6.0% (42 mmol/mol) at each trimester was achieved by 20.9% (74/354), 65.1% (207/318), and 58.0% (148/255), respectively. For women using CSII + CGM versus CSII only, HbA1c levels at trimesters 1, 2, and 3 were 6.5 ± 0.9% versus 7.1 ± 1.3% (47.8 ± 9.7 mmol/mol versus 54.3 ± 14.0 mmol/mol, p < 0.0001), 5.7 ± 0.6% versus 6.0 ± 0.9% (38.9 ± 6.5 mmol/mol versus 41.6 ± 9.3 mmol/mol, p = 0.0122), and 5.8 ± 0.6% versus 6.1 ± 0.8% (40.3 ± 6.9 mmol/mol versus 42.9 ± 9.1 mmol/mol, p = 0.0117), respectively. For the overall, CSII only, and CSII + CGM groups, rates of LGA delivery were 22.7% (74/326), 24.6% (34/138), and 21.3% (40/188), respectively.

CONCLUSIONS

Observational assessment of women with T1D using CSII therapy demonstrated low HbA1c throughout pregnancy and low rates of LGA. The addition of CGM to CSII therapy compared to CSII therapy alone was associated with some improved maternal glycemic and neonatal outcomes.

GOV IDENTIFIER

NCT01779141 (January 2013).

Time in Range and Pregnancy Outcomes in People with Diabetes Using Continuous Glucose Monitoring

OBJECTIVE

 The international consensus on continuous glucose monitoring (CGM) recommends time in range (TIR) target of >70% for pregnant people. Our aim was to compare outcomes between pregnant people with TIR ≤ versus >70%.

STUDY DESIGN

 This study was a retrospective study of all people using CGM during pregnancy from January 2017 to May 2021 at a tertiary care center. All people with pregestational diabetes who used CGM and delivered at our center were included in the analysis. Primary neonatal outcome included any of the following: large for gestational age, neonatal intensive care unit (NICU) admission, need for intravenous (IV) glucose, or respiratory distress syndrome (RDS). Maternal outcomes included hypertensive disorders of pregnancy and delivery outcomes. Logistic regression was used to estimate unadjusted and adjusted odds ratios (aORs) with 95% confidence intervals (CIs).

RESULTS

 Of 78 people managed with CGM, 65 (80%) met inclusion criteria. While 33 people (50.1%) had TIR ≤70%, 32 (49.2%) had TIR >70%. People with TIR ≤70% were more likely to be younger, have a lower body mass index, and have type 1 diabetes than those with TIR >70%. After multivariable regression, there was no difference in the composite neonatal outcome between the groups (aOR: 0.56, 95% CI: 0.16-1.92). However, neonates of people with TIR ≤70% were more likely to be admitted to the NICU (p = 0.035), to receive IV glucose (p = 0.005), to have RDS (p = 0.012), and had a longer hospital stay (p = 0.012) compared with people with TIR >70%. Furthermore, people with TIR ≤70% were more likely to develop hypertensive disorders (p = 0.04) than those with TIR >70%.

CONCLUSION

 In this cohort, the target of TIR >70% was reached in about one out of two people with diabetes using CGM, which correlated with a reduction in neonatal and maternal complications.

KEY POINTS

· Among people with diabetes, 50% reached the recommended time in range using CGM.. · Time in range >70% was associated with reducing the rate of some neonatal complications.. · Time in range ≤70% was associated with increased risk for adverse maternal outcomes..

Roux-en-Y Gastric Bypass Increases Glycemic Excursions During Pregnancy and Postpartum: A Prospective Cohort Study

OBJECTIVE

Roux-en-Y gastric bypass (RYGB) and pregnancy markedly alter glucose metabolism, but evidence on glucose metabolism in pregnancy after RYGB is limited. Thus, the aims of the Bariatric Surgery and Consequences for Mother and Baby in Pregnancy study were to investigate interstitial glucose (IG) profiles during pregnancy, risk factors associated with hypoglycemia, and the association between fetal growth and hypoglycemia in pregnant women previously treated with RYGB, compared with control participants.

RESEARCH DESIGN AND METHODS

Twenty-three pregnant women with RYGB and 23 BMI- and parity-matched pregnant women (control group) were prospectively studied with continuous glucose monitoring in their first, second, and third trimesters, and 4 weeks postpartum. Time in range (TIR) was defined as time with an IG level of 3.5-7.8 mmol/L.

RESULTS

Women with RYGB were 4 years (interquartile range [IQR] 0-7) older than control participants. Pregnancies occurred 30 months (IQR 15-98) after RYGB, which induced a reduction in BMI from 45 kg/m2 (IQR 42-54) presurgery to 32 kg/m2 (IQR 27-39) prepregnancy. Women with RYGB spent decreased TIR (87.3-89.5% vs. 93.3-96.1%; P < 0.01) owing to an approximately twofold increased time above range and increased time below range (TBR) throughout pregnancy and postpartum compared with control participants. Women with increased TBR had a longer surgery-to-conception interval, lower nadir weight, and greater weight loss after RYGB. Finally, women giving birth to small-for-gestational age neonates experienced slightly increased TBR.

CONCLUSIONS

Women with RYGB were more exposed to hypoglycemia and hyperglycemia during pregnancy compared with control participants. Further research should investigate whether hypoglycemia during pregnancy in women with RYGB is associated with decreased fetal growth.

Expert Guidance on Off-Label Use of Hybrid Closed-Loop Therapy in Pregnancies Complicated by Diabetes

Automated insulin delivery (AID) systems have established benefits in terms of glycemic control, health outcomes, and quality of life and are strongly recommended for people with type 1 diabetes outside of pregnancy. While evidence for use of investigational AID systems during pregnancy is promising, data and guidance are still needed regarding use of commercially available systems during pregnancy. Unfortunately, none of the hybrid closed-loop (HCL) systems that are currently available in the United States have glucose targets that are as aggressive as pregnancy glycemic targets, none have a pregnancy-specific algorithm, and none are approved for use during pregnancy. As such, any use of these systems during pregnancy is considered off-label in the United States and would be "assisted" by provider/user techniques. Despite these limitations, many women conceive while using clinically available HCL systems and may be hesitant to cease use during pregnancy. Achievement of strict pregnancy glycemic targets can be difficult, and it is conceivable that selective off-label use of clinically available HCL systems in some women could lead to improved glycemia. We herein offer expert guidance based on clinical experience and available case reports on how to identify appropriate candidates for HCL therapy in pregnancy, how to counsel pregnant women with diabetes on the potential risks and benefits of HCL therapy during pregnancy, and how to manage commercially available systems off-label throughout gestation in an assisted HCL approach.

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.

Glycaemic control and novel technology management strategies in pregestational diabetes mellitus

Introduction

Pregestational diabetes (PGDM) is an increasingly common and complex condition that infers risk to both mother and infant. To prevent serious morbidity, strict glycaemic control is essential. The aim of this review is to review the glucose sensing and insulin delivering technologies currently available for women with PGDM.

Methods

We reviewed online databases for articles relating to technology use in pregnancy using a combination of keywords and MeSH headings. Relevant articles are included below.

Results

A number of technological advancements have improved care and outcomes for women with PGDM. Real time continuous glucose monitoring (rtCGM) offers clear advantages in terms of infants size and neonatal intensive care unit admissions; and further benefits are seen when combined with continuous subcutaneous insulin delivery (insulin pump) and algorithms which continuously adjust insulin levels to glucose targets (hybrid closed loop). Other advancements including flash or intermittent scanning CGM (isCGM) and stand-alone insulin pumps do not confer as many advantages for women and their infants, however they are increasingly used outside of pregnancy and many women enter pregnancy already using these devices.

Discussion

This article offers a discussion of the most commonly used technologies in pregnancy and evaluates their current and future roles.

Glycemic Variability in Type 1 Diabetes Mellitus Pregnancies—Novel Parameters in Predicting Large-for-Gestational-Age Neonates: A Prospective Cohort Study

Pregnancies with type 1 diabetes mellitus (T1DM) have a high incidence of large-for-gestational-age neonates (LGA) despite optimal glycemic control. In recent years, glycemic variability (GV) has emerged as a possible risk factor for LGA, but the results of the conducted studies are unclear. This study analyzed the association between GV and LGA development in pregnancies with T1DM. This was a prospective cohort study of patients with T1DM who used continuous glucose monitoring (CGM) during pregnancy. Patients were followed from the first trimester to birth. GV parameters were calculated for every trimester using the EasyGV calculator. The main outcomes were LGA or no-LGA. Logistic regression analysis was used to assess the association between GV parameters and LGA. In total, 66 patients were included. The incidence of LGA was 36%. The analysis extracted several GV parameters that were significantly associated with the risk of LGA. The J-index was the only significant parameter in every trimester of pregnancy (odds ratios with confidence intervals were 1.33 (1.02, 1.73), 3.18 (1.12, 9.07), and 1.37 (1.03, 1.82), respectively. Increased GV is a risk factor for development of LGA. The J-index is a possible novel GV parameter that may be assessed in all three trimesters of pregnancy together with glycated hemoglobin and time-in-range.

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.

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.

Clinical usefulness of glycated albumin and glycated albumin-to-glycated hemoglobin ratio of gestational diabetes mellitus in late pregnancy for predicting infant complications

BACKGROUND

Gestational diabetes mellitus (GDM) with poorly controlled glycemia is associated with poor pregnancy outcomes. However, adequate markers for glycemic control in GDM have not been fully evaluated.

METHODS

We retrospectively studied 77 patients with GDM and their infants. Mean glycated albumin (GA), glycated hemoglobin (HbA1c), and GA/HbA1c in GDM were compared between two groups stratified by the presence or absence of infant complications (complications or non-complications). We assessed the predictability of infant complications in GA, HbA1c, and GA/HbA1c of women with GDM by receiver operating characteristic analysis (ROC).

RESULTS

In complications and non-complications, GA and GA/HbA1c were significantly associated with neonatal hypoglycemia (13.9% vs. 13.0%, p < 0.001 and 2.49 vs. 2.33, p < 0.001, respectively), respiratory disorders (13.7% vs. 13.2%, p = 0.013 and 2.48 vs. 2.34, p < 0.001, respectively), myocardial hypertrophy (14.5% vs. 13.0%, p < 0.001 and 2.59 vs. 2.33, p < 0.001, respectively), and large for gestational age (14.5% vs. 13.1%, p < 0.001 and 2.58 vs. 2.34, p < 0.001, respectively). Compared with each infant complication in ROC, GA and GA/HbA1c had higher area under the curve than HbA1c. Especially, GA and GA/HbA1c had highest AUC in predicting myocardial hypertrophy and large for gestational age (GA; 0.92 and 0.92, GA/HbA1c; 0.91 and 0.86, respectively). Although statistically significant positive correlations were found between GA and GA/HbA1c and the number of infant complications (GA: r = 0.417, p < 0.001; GA/HbA1c: r = 0.408, p < 0.001), their correlations were weak.

CONCLUSION

Compared with HbA1c, GA and GA/HbA1c of GDM in late pregnancy might be useful for predicting infant complications arising from GDM.

Longitudinal Associations Between Maternal Glucose Levels and Ultrasonographic Fetal Biometrics in a Shanghai Cohort

IMPORTANCE

Evidence on the timing of fetal growth alterations associated with gestational diabetes or on the association of the maternal glycemic trajectory with fetal growth during pregnancy remains lacking.

OBJECTIVE

To examine the associations between maternal glucose levels and offspring intrauterine growth.

DESIGN, SETTING, AND PARTICIPANTS

This cohort study used data from 4574 eligible pregnant women and their offspring in the Shanghai Maternal-Child Pairs Cohort collected from April 10, 2016, to April 30, 2018. Group-based trajectory modeling was used to classify fasting plasma glucose levels during pregnancy into 3 glycemic trajectories (trajectory 1, consistently normal glucose levels in all 3 trimesters; trajectory 2, hyperglycemia only in late pregnancy; and trajectory 3, hyperglycemia in all 3 trimesters [ie, consistently high glucose levels]). Statistical analysis was performed from April 25, 2020, to October 1, 2021.

EXPOSURES

Gestational diabetes, which was defined using the results of an oral glucose tolerance test.

MAIN OUTCOMES AND MEASURES

Longitudinal fetal biometrics during gestational weeks 11 to 40 and birth outcomes were obtained from medical records. Pregnancy was partitioned into 3 periods (<24, 24-34, and >34 weeks' gestational age). The differences in offspring growth (log-transformed) and maternal glucose levels were compared using generalized linear mixed models.

RESULTS

A total of 4121 pregnant women had oral glucose tolerance test results (mean [SD] age, 28.8 [4.1] years), 3746 of whom had glycemic trajectory data (mean [SD] age, 28.6 [4.1] years); 983 women (23.8%) had gestational diabetes. Throughout the pregnancy period and compared with the women without gestational diabetes or with women in the trajectory 1 group, the fetal biometrics for the women with gestational diabetes or for those in the trajectory 3 group were significantly higher (except for biparietal diameter), with an estimated increase in fetal weight in the group with gestational diabetes (β = 1.82; 95% CI, 1.03-2.61) and in the trajectory 3 group (β = 1.50; 95% CI, 0.54-2.47; P = .002). Fetal biometric alterations among women with gestational diabetes appeared before 24 weeks' gestational age, with neonatal birth weight significantly higher than in the group without gestational diabetes at 40.4 g (95% CI, 9.8-71.1 g) along with an increased risk of large size for gestational age (odds ratio, 1.36; 95% CI, 1.05-1.75) and macrosomia (odds ratio, 1.47; 95% CI, 1.12-1.94). However, pregnant women in the trajectory 2 group manifested significantly reduced fetal biometrics, and abdominal circumference was significantly augmented after 34 weeks' gestational age (increase, β = 1.92; 95% CI, 0.87-2.99).

CONCLUSIONS AND RELEVANCE

In this cohort study, pregnant women who received a diagnosis of gestational diabetes in midpregnancy or had hyperglycemia during all 3 trimesters showed an association with altered fetal growth patterns, including increased estimated fetal weight that appeared before 24 weeks' gestational age, increased birth weight, and the risk for large size for gestational age and macrosomia.

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.

A prospective study of the relationships between movement and glycemic control during day and night in pregnancy

Both disturbed sleep and lack of exercise can disrupt metabolism in pregnancy. Accelerometery was used to objectively assess movement during waking (physical activity) and movement during sleeping (sleep disturbance) periods and evaluated relationships with continuous blood glucose variation during pregnancy. Data was analysed prospectively. 15-women without pre-existing diabetes mellitus wore continuous glucose monitors and triaxial accelerometers from February through June 2018 in Sweden. The relationships between physical activity and sleep disturbance with blood glucose rate of change were assessed. An interaction term was fitted to determine difference in the relationship between movement and glucose variation, conditional on waking/sleeping. Total movement was inversely related to glucose rate of change (p < 0.001, 95% CI (− 0.037, − 0.026)). Stratified analyses showed total physical activity was inversely related to glucose rate of change (p < 0.001, 95% CI (− 0.040, − 0.028)), whereas sleep disturbance was not related to glucose rate of change (p = 0.07, 95% CI (< − 0.001, 0.013)). The interaction term was positively related to glucose rate of change (p < 0.001, 95% CI (0.029, 0.047)). This study provides temporal evidence of a relationship between total movement and glycemic control in pregnancy, which is conditional on time of day. Movement is beneficially related with glycemic control while awake, but not during sleep.

Assessing Glycemic Control Using CGM for Women with Diabetes in Pregnancy

PURPOSE OF REVIEW

Diabetes during pregnancy increases the risk of maternal and fetal complications. This article reviews the types of CGM currently available, the glucose metrics which correlate with pregnancy outcomes, endocrine organization recommendations, clinical considerations for CGM implementation, and anticipated directions for future research.

RECENT FINDINGS

CGM use during pregnancy is increasing, and recommendations for use have been incorporated into many organizations' consensus guidelines. Increased time spent within a target range of 63-140 mg/dL and lower mean glucose are associated with lower risk of neonatal complications including large for gestational age infants. Use of CGM during pregnancy can detect postprandial and nocturnal hyperglycemia missed by self-monitoring of blood glucose (SMBG) which can be used for prognosis and to guide pharmacologic interventions. The use of continuous glucose monitoring (CGM) during pregnancies complicated by type 1, type 2, and gestational diabetes has been shown to improve outcomes.

Identification of maternal continuous glucose monitoring metrics related to newborn birth weight in pregnant women with gestational diabetes

PURPOSE

To identify the specific glucose metrics derived from maternal continuous glucose monitoring (CGM) data, which were associated with a higher percentile of offspring birth weight.

METHODS

In this cohort study, we recruited singleton pregnant women with GDM who underwent CGM for 5-14 days at a mean of 28.8 gestational weeks between Jan 2017 and Nov 2018. Commonly used single summary glucose metrics of glucose exposure (including mean 24-h, daytime, and nighttime glucose level) and variability (including J-index and mean amplitude of glycaemic excursions) were derived from CGM data. A novel comprehensive glucose metric-hours per-day spent in a severe variability glucose mode (HSSV)-was identified using the spectral clustering method, which reflects both glucose level and variability. Multiple linear regression models were used to estimate the associations of sex- and gestational age-adjusted birth weight percentile with CGM parameters.

RESULTS

Ninety-seven women comprising 127,279 glucose measurements were included. Each 1-SD increase in maternal nighttime mean glucose level and HSSV was associated with 6.0 (95% CI 0.4, 11.5) and 6.3 (95% CI 0.4, 12.2) percentage points increase in birth weight percentile, respectively. No associations were found between other glucose metrics and birth weight percentile.

CONCLUSION

Nighttime mean glucose level has a comparable effect size to HSSV in association with fetal growth, suggesting that endogenous hyperglycemia might drive the association between maternal hyperglycemia and birth weight. Further studies need to examine the effect of lowering nighttime glucose level and/or HSSV on preventing fetal overgrowth in GDM women.

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.

Profiles of Intraday Glucose in Type 2 Diabetes and Their Association with Complications: An Analysis of Continuous Glucose Monitoring Data

Aims: To identify profiles of type 2 diabetes from continuous glucose monitoring (CGM) data using ambulatory glucose profile (AGP) indicators and examine the association with prevalent complications. Methods: Two weeks of CGM data, collected between 2015 and 2019, from 5901 adult type 2 diabetes patients were retrieved from a clinical database in Chennai, India. Non-negative matrix factorization was used to identify profiles as per AGP indicators. The association of profiles with existing complications was examined using multinomial and logistic regressions adjusted for glycated hemoglobin (HbA1c; %), sex, age at onset, and duration of diabetes. Results: Three profiles of glycemic variability (GV) were identified based on CGM data-Profile 1 ["TIR Profile"] (n = 2271), Profile 2 ["Hypo"] (n = 1471), and Profile 3 ["Hyper"] (n = 2159). Compared with time in range (TIR) profile, those belonging to Hyper had higher mean fasting plasma glucose (202.9 vs. 167.1, mg/dL), 2-h postprandial plasma glucose (302.1 vs. 255.6, mg/dL), and HbA1c (9.7 vs. 8.6; %). Both "Hypo profile" and "Hyper profile" had higher odds of nonproliferative diabetic retinopathy ("Hypo": 1.44, 1.20-1.73; "Hyper": 1.33, 1.11-1.58), macroalbuminuria ("Hypo": 1.58, 1.25-1.98; "Hyper": 1.37, 1.10-1.71), and diabetic kidney disease (DKD; "Hypo": 1.65, 1.18-2.31; "Hyper": 1.88, 1.37-2.58), compared with "TIR profile." Those in "Hypo profile" (vs. "TIR profile") had higher odds of proliferative diabetic retinopathy (PDR; 2.84, 1.65-2.88). Conclusions: We have identified three profiles of GV from CGM data. While both "Hypo profile" and "Hyper profile" had higher odds of prevalent DKD compared with "TIR profile," "Hypo profile" had higher odds of PDR. Our study emphasizes the clinical importance of recognizing and treating hypoglycemia (which is often unrecognized without CGM) in patients with type 2 Diabetes Mellitus.

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.

Glycaemic Variability and Risk Factors of Pregnant Women with and without Gestational Diabetes Mellitus Measured by Continuous Glucose Monitoring

Background: The aim of the study was to compare the continuous glucose monitoring (CGM)-determined glycaemic variability (GV) of pregnant women with gestational diabetes mellitus (GDM) and without GDM (CG; control group). The secondary aim was to evaluate the association between risk factors of diabetes in pregnancy and parameters of glyceamic control. Methods: Demographic, biometric and biochemical parameters were obtained for pregnant women (20-38 years old) who after an oral glucose tolerance test were examined by 7-day continuous glucose monitoring using a iPro^®2 Professional CGM. Results: The differences in GV between women with GDM and CG compared by total area under glucose curve (total AUC, (mmol·day/L) was statistically significant (p = 0.006). Other parameters of glycaemic control such as mean glucose, standard deviation, coefficient of variation, J-index, % time-above target range 7.8 mmol/L (%TAR), % time-in range 3.5-7.8 mmol/L (%TIR), time-below target range 3.5 mmol/L (%TBR), glycated haemoglobin were not significantly different in the study groups. Risk factors (a family history of diabetes, pre-pregnancy BMI, higher weight gain and age) correlated with parameters of glycaemic control. Conclusions: We found a significant difference in GV of women with and without GDM by total AUC determined from CGM. TIR metrics were close to significance. Our work points at an increased GV in relation to the risk factors of GDM. Pregnant women with risk factors have higher probability of severe GV with its consequences on maternal and fetal health state.

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

OBJECTIVE

The optimal method of monitoring glycemia in pregnant women with type 1 diabetes remains controversial. This study aimed to assess the predictive performance of HbA_1c, continuous glucose monitoring (CGM) metrics, and alternative biochemical markers of glycemia to predict obstetric and neonatal outcomes.

RESEARCH DESIGN AND METHODS

One hundred fifty-seven women from the Continuous Glucose Monitoring in Women With Type 1 Diabetes in Pregnancy Trial (CONCEPTT) were included in this prespecified secondary analysis. HbA_1c, CGM data, and alternative biochemical markers (glycated CD59, 1,5-anhydroglucitol, fructosamine, glycated albumin) were compared at ∼12, 24, and 34 weeks' gestation using logistic regression and receiver operating characteristic (ROC) curves to predict pregnancy complications (preeclampsia, preterm delivery, large for gestational age, neonatal hypoglycemia, admission to neonatal intensive care unit).

RESULTS

HbA_1c, CGM metrics, and alternative laboratory markers were all significantly associated with obstetric and neonatal outcomes at 24 weeks' gestation. More outcomes were associated with CGM metrics during the first trimester and with laboratory markers (area under the ROC curve generally <0.7) during the third trimester. Time in range (TIR) (63-140 mg/dL [3.5-7.8 mmol/L]) and time above range (TAR) (>140 mg/dL [>7.8 mmol/L]) were the most consistently predictive CGM metrics. HbA_1c was also a consistent predictor of suboptimal pregnancy outcomes. Some alternative laboratory markers showed promise, but overall, they had lower predictive ability than HbA_1c.

CONCLUSIONS

HbA_1c is still an important biomarker for obstetric and neonatal outcomes in type 1 diabetes pregnancy. Alternative biochemical markers of glycemia and other CGM metrics did not substantially increase the prediction of pregnancy outcomes compared with widely available HbA_1c and increasingly available CGM metrics (TIR and TAR).

What is known and what remains unresolved regarding gestational diabetes mellitus (GDM)

Gestational diabetes mellitus (GDM) has become a major public health issue and one of the most discussed topics in contemporary obstetrics. Due to rising prevalence of GDM worldwide impact and importance of this medical condition in good quality antenatal care is growing. GDM is associated with serious adverse perinatal outcomes and unfavorable long-term health consequences for both, mother and her child. Despite a great amount of knowledge accumulated regarding GDM, medical community remains indecisive and still debates the most appropriate diagnostic strategy, screening policy, and treatment options for pregnancies complicated with GDM. These unresolved issues generate controversies, motivate further research and contribute to the growing interest surrounding GDM. In this review we will discuss and try to explain some of them.

Leveraging technology for the treatment of type 1 diabetes in pregnancy: A review of past, current, and future therapeutic tools

The significant risks associated with pregnancies complicated by type 1 diabetes (T1D) were first recognized in the medical literature in the mid-twentieth century. Stringent glycemic control with hemoglobin A1c (HbA1c) values ideally less than 6% has been shown to improve maternal and fetal outcomes. The management options for pregnant women with T1D in the modern era include a variety of technologies to support self-care. Although self-monitoring of blood glucose (SMBG) and multiple daily injections (MDI) are often the recommended management options during pregnancy, many people with T1D utilize a variety of different technologies, including continuous glucose monitoring (CGM), continuous subcutaneous insulin infusion (CSII), and CSII including automated delivery or suspension algorithms. These systems have yielded invaluable diagnostic and therapeutic capabilities and have the potential to benefit this understudied higher-risk group. A recent prospective, multicenter study evaluating pregnant patients with T1D revealed that CGM significantly improves maternal glycemic parameters, is associated with fewer adverse neonatal outcomes, and minimizes burden. Outcome data for CSII, which is approved for use in pregnancy and has been utilized for several decades, remain mixed. Current evidence, although limited, for commercially available and emerging technologies for the management of T1D in pregnancy holds promise for improving patient and fetal outcomes.

Functional data analysis and prediction tools for continuous glucose-monitoring studies

Introduction

To identify phenotypes of type 1 diabetes based on glucose curves from continuous glucose-monitoring (CGM) using functional data (FD) analysis to account for longitudinal glucose patterns. We present a reliable prediction model that can accurately predict glycemic levels based on past data collected from the CGM sensor and real-time risk of hypo-/hyperglycemic for individuals with type 1 diabetes.

Methods

A longitudinal cohort study of 443 type 1 diabetes patients with CGM data from a completed trial. The FD analysis approach, sparse functional principal components (FPCs) analysis was used to identify phenotypes of type 1 diabetes glycemic variation. We employed a nonstationary stochastic linear mixed-effects model (LME) that accommodates between-patient and within-patient heterogeneity to predict glycemic levels and real-time risk of hypo-/hyperglycemic by creating specific target functions for these excursions.

Results

The majority of the variation (73%) in glucose trajectories was explained by the first two FPCs. Higher order variation in the CGM profiles occurred during weeknights, although variation was higher on weekends. The model has low prediction errors and yields accurate predictions for both glucose levels and real-time risk of glycemic excursions.

Conclusions

By identifying these distinct longitudinal patterns as phenotypes, interventions can be targeted to optimize type 1 diabetes management for subgroups at the highest risk for compromised long-term outcomes such as cardiac disease or stroke. Further, the estimated change/variability in an individual's glucose trajectory can be used to establish clinically meaningful and patient-specific thresholds that, when coupled with probabilistic predictive inference, provide a useful medical-monitoring tool.

Need for less tight glucose control in early pregnancy after embryogenesis due to high risk of maternal hypoglycaemia in women with pre-existing diabetes can be compensated by good control in late pregnancy

AIM

Poor glucose control is associated with adverse outcomes in pregnancies with pre-existing diabetes. However, strict glucose control increases the risk of severe hypoglycaemia, particularly in the first trimester. Therefore, we aimed to investigate whether less tight glucose control in the first trimester determines adverse outcomes or can be compensated for by good control in late pregnancy.

METHODS

Retrospective data were collected from 517 singleton pregnancies complicated by pre-existing diabetes delivering between 2010 and 2017. Three hundred and thirty-six pregnancies fulfilled the inclusion criteria of having available HbA_1c values either pre-conception or in the first trimester (65% type 1 diabetes, 35% type 2 diabetes).

RESULTS

Higher HbA_1c values in the first trimester were associated with increasing rates of large for gestational age (LGA) neonates, preterm delivery or neonatal intensive care unit admissions. Multiple regression analysis demonstrated third trimester HbA_1c , type 1 diabetes, multiparity and excess weight gain, but not first trimester HbA_1c , to be independently predictive for LGA. Pre-eclampsia and third trimester HbA_1c increased the risk for preterm delivery. If HbA_1c was ≤ 42 mmol/mol (6.0%) in the third trimester, rates of adverse outcomes were not significantly higher even if HbA_1c targets of ≤ 48 mmol/mol (6.5%) had not been met in the first trimester. Good first trimester glucose control did not modify the rates of adverse outcomes if HbA_1c was > 42 mmol/mol (6.0%) in the third trimester.

CONCLUSIONS

Less tight glycaemic control, for example due to high frequency of severe hypoglycaemia in the first trimester, does not lead to increased adverse neonatal events if followed by tight control in the third trimester. Besides glycaemic control, excess weight gain is a modifiable predictor of adverse outcome.

Time trends in pregnancy-related outcomes among women with type 1 diabetes mellitus, 2004-2017

OBJECTIVE

To examine time trends in US pregnant women with type 1 diabetes mellitus for maternal characteristics and pregnancy outcomes.

STUDY DESIGN

We abstracted clinical data from the medical records of 700 pregnant women from 2004 to 2017. For each time period, means and percentages were calculated. P values for trend were calculated using linear and logistic regression.

RESULTS

HbA1c in each trimester was unchanged across the analysis period. The prevalence of nephropathy decreased from 4.8% to 0% (P = 0.002). Excessive gestational weight gain increased (P = 0.01). Gestation length also increased (P = 0.01), as did vaginal deliveries (P = 0.03). There were no change in birthweight over time (P = 0.07) and the percentage of neonates with macrosomia and large for gestational age (LGA) neonates also remained unchanged.

CONCLUSION

Obstetric guideline changes may have improved gestation length and mode of delivery; however, other outcomes need more attention, including excessive gestational weight gain, macrosomia, and LGA.

Maternal Sleep-Disordered Breathing in Pregnancy and Increased Nocturnal Glucose Levels in Women with Gestational Diabetes Mellitus

BACKGROUND

Women with hyperglycemia during pregnancy are at high risk for adverse perinatal outcomes. Maternal sleep-disordered breathing (SDB) during pregnancy is common and is a risk factor for gestational diabetes mellitus (GDM). However, the relationship between SDB severity and glucose control is unknown.

RESEARCH QUESTION

Is there an association between SDB severity and glucose levels as assessed by continuous glucose monitoring in GDM?

STUDY DESIGN AND METHODS

Women with GDM underwent sleep recordings and 72-hour continuous glucose monitoring. Linear mixed models were used to estimate the association of the apnea-hypopnea index (AHI), rapid eye movement (REM)-AHI, and non-REM-AHI with mean glucose levels during nighttime (two periods: 11 pm to 3 am and 3 am to 6 am), daytime (8 am to 9 pm), and 24-hours. Models were adjusted for BMI and antihyperglycemic medications.

RESULTS

In 65 participants who were 35 ± 5 (mean ± SD) years of age with BMI of 33 ± 7 kg/m², 31% were undergoing insulin and/or metformin therapy. A ten-unit increase in AHI was associated with elevated nocturnal glucose levels (11 pm to 3 am: 0.20 mmol/L [95% CI, 0.04-0.40]) with persistent elevations into the morning (8 am: 0.26 mmol/L [95% CI, 0.08-0.4]) when adjusted for BMI and medications. REM-AHI was also associated with higher nocturnal and morning glucose levels, whereas non-REM was not. AHI was not associated with either mean daytime or 24-hour glucose levels.

INTERPRETATION

Greater severity of SDB was associated with higher nocturnal and morning glucose levels in women with GDM.

Continuous Glucose Monitoring in Pregnancy: Importance of Analyzing Temporal Profiles to Understand Clinical Outcomes

OBJECTIVE

To determine if temporal glucose profiles differed between 1) women who were randomized to real-time continuous glucose monitoring (RT-CGM) or self-monitored blood glucose (SMBG), 2) women who used insulin pumps or multiple daily insulin injections (MDIs), and 3) women whose infants were born large for gestational age (LGA) or not, by assessing CGM data obtained from the Continuous Glucose Monitoring in Women With Type 1 Diabetes in Pregnancy Trial (CONCEPTT).

RESEARCH DESIGN AND METHODS

Standard summary metrics and functional data analysis (FDA) were applied to CGM data from the CONCEPTT trial (RT-CGM, n = 100; SMBG, n = 100) taken at baseline and at 24- and 34-weeks' gestation. Multivariable regression analysis determined if temporal differences in 24-h glucose profiles occurred between comparators in each of the three groups.

RESULTS

FDA revealed that women using RT-CGM had significantly lower glucose (0.4-0.8 mmol/L [7-14 mg/dL]) for 7 h/day (0800 h to 1200 h and 1600 h to 1900 h) compared with those with SMBG. Women using pumps had significantly higher glucose (0.4-0.9 mmol/L [7-16 mg/dL]) for 12 h/day (0300 h to 0600 h, 1300 h to 1800 h, and 2030 h to 0030 h) at 24 weeks with no difference at 34 weeks compared with MDI. Women who had an LGA infant ran a significantly higher glucose by 0.4-0.7 mmol/L (7-13 mg/dL) for 4.5 h/day at baseline, by 0.4-0.9 mmol/L (7-16 mg/dL) for 16 h/day at 24 weeks, and by 0.4-0.7 mmol/L (7-13 mg/dL) for 14 h/day at 34 weeks.

CONCLUSIONS

FDA of temporal glucose profiles gives important information about differences in glucose control and its timing, which are undetectable by standard summary metrics. Women using RT-CGM were able to achieve better daytime glucose control, reducing fetal exposure to maternal glucose.

Evaluation of Glycaemic Control, Glucose Variability and Hypoglycaemia on Long-Term Continuous Subcutaneous Infusion vs. Multiple Daily Injections: Observational Study in Pregnancies With Pre-Existing Type 1 Diabetes

INTRODUCTION

We evaluated the effectiveness of long-term continuous subcutaneous insulin infusion (CSII) compared with multiple daily insulin (MDI) injections for glycaemic control and variability, hypoglycaemic episodes and maternal/neonatal outcomes in pregnant women with pre-existing type 1 diabetes (pT1D).

METHODS

Our observational cohort study included 128 consecutive pregnant women with pT1D, who were treated from 1 January 2010 to 31 December 2017. Of 128 participants, 48 were on CSII and 80 were on MDI. Glycaemic control was determined by glycated haemoglobin (HbA1c) (captured in preconception and each trimester of pregnancy). Glucose variability (GV) was expressed as the coefficient of variation (CV) [calculated from self-monitoring of blood glucose (SMBG) values], and hypoglycaemia was defined as glucose values < 3.9 mmol/l. The data on maternal and neonatal outcomes were collected from obstetrical records.

RESULTS

Duration of the treatment was 8.8 ± 5.3 years in the CSII and 12.6 ± 8.0 years in the MDI group. The CSII lowered HbA1c in preconception (7.1 ± 0.1 vs. 7.9 ± 0.2%, p = 0.03) and the first (6.9 ± 0.1 vs. 7.7 ± 0.2%, p = 0.02), second (6.6 ± 0.1 vs. 7.2 ± 0.1%, p = 0.003) and third (6.5 ± 0.1 vs. 6.8 ± 0.1%, p = 0.02) trimesters significantly better than MDI. Significantly lower CV was observed only for fasting glycaemia in the first trimester (17.1 vs 28.4%, p < 0.001) in favour of CSII. Moreover, the CSII group had significantly lower mean hypoglycaemic episodes/week/patient only during the first trimester (2.0 ± 1.7 vs 4.8 ± 1.5, p < 0.01). In early pregnancy, the majority of women on CSII had less hypoglycaemia than on MDI (0-3: 79.1 vs. 29.1%; 4-6: 18.8 vs. 65.8%; ≥ 7: 2.1 vs. 5.1%, p < 0.01, respectively). We found no difference in the incidence of adverse maternal/neonatal outcomes.

CONCLUSIONS

Treatment with CSII resulted in a favourable reduction of HbA1c in the preconception period and each trimester in pregnancy. Moreover, long-term CSII treatment demonstrated more stable metabolic control with less GV of fasting glycaemia and fewer hypoglyacemic episodes only during early pregnancy.