Continuous glucose monitor use in type 2 diabetes mellitus in pregnancy and perinatal outcomes: a systematic review and meta-analysis

One-hour vs. two-hour postprandial glucose targets and fetomaternal outcomes in gestational diabetes mellitus: A systematic review and meta-analysis

OBJECTIVE

The optimal time and target for postprandial glucose (PPG) measurement in gestational diabetes mellitus (GDM) remain unclear. This systematic review and meta-analysis evaluated whether targeting 1-hour PPG (1hPG) vs. 2-hour PPG (2hPG) altered fetomaternal outcomes in GDM.

METHODS

Studies that compared pregnancy outcomes in women undergoing 1hPG vs. 2hPG monitoring in GDM were identified through comprehensive search of electronic databases. Primary outcomes analyzed were large-for-gestational age (LGA) and macrosomia. Secondary outcomes included low birthweight (LBW), neonatal intensive-care unit (NICU) admission, neonatal hypoglycemia, cesarean section (CS), preeclampsia, gestational age at delivery and preterm delivery.

RESULTS

Six articles that compared 1hPG<140mg/dL (7.8mmol/L) vs. 2hPG <120mg/dL (7.2 mmol/L) were analyzed. Additionally, three articles that assessed 1hPG<120mg/dL vs 1hPG<140mg/dL were also examined. Targeting 1hPG<140mg/dL vs. 2hPG<120mg/dL significantly lowered the risk of LGA [OR 0.54; 95%CI:0.32-0.93;P=.03] but not macrosomia [OR 0.45; 95%CI:0.19-1.06;P=.07]. There was no difference in other parameters such as birthweight [MD -61.77g; 95%CI:-152.16-28.62;P=.018], LBW [OR 0.90; 95%CI:0.30-2.68;P=0.85], neonatal hypoglycemia [OR 0.60; 95%CI:0.28-1.26;P=0.18], gestational age at delivery [MD 0.20weeks; 95%CI:-0.29-0.68;P=0.43], CS [OR 0.99; 95%CI:0.46-2.12;P=0.97], preeclampsia [OR 0.66;95% CI:.22-1.96;P=0.46], or need for insulin therapy [OR 1.39; 95%CI:.79-2.43;P=0.25;]. More intensive 1hPG target <120mg/dl vs. <140mg/dl increased the risk of preterm delivery [OR 1.62; 95%CI:1.00-2.62;P=0.05], without affecting birthweight, LGA, macrosomia, LBW, and CS.

CONCLUSION

Our findings suggest that targeting 1hPG <140mg/dL vs. 2hPG<140mg/dL lowers the risk of LGA, but does not affect other parameters. A stricter target of 1hPG<120mg/dL can increase the risk of preterm delivery. Further studies to corroborate these findings are necessary.

Evidence for improved glucose metrics and perinatal outcomes with continuous glucose monitoring compared to self-monitoring in diabetes during pregnancy

OBJECTIVE

Continuous glucose monitoring is recommended for pregnant women with type 1 diabetes, due to associations with decreased hemoglobin A1c and large for gestational age. However, its benefit in type 2 diabetes and gestational diabetes is not established. This systematic review and meta-analysis compared usage of continuous glucose monitoring to self-monitoring of blood glucose both across and within diabetes in pregnancy and determined which glucose metrics are associated with perinatal outcomes, to potentially inform treatment targets in diabetes in pregnancy.

DATA SOURCES

We searched Medline, Embase, CENTRAL, CINAHL, and Scopus, from January 2003 to August 2024.

STUDY ELIGIBILITY CRITERIA

Randomized controlled trials and quasi-experimental studies comparing continuous glucose monitoring with self-monitoring of blood glucose in diabetes in pregnancy were included.

STUDY APPRAISAL AND SYNTHESIS METHODS

Randomized controlled trials and quasi-experimental studies were analyzed separately. Data were extracted on continuous glucose monitoring metrics, hemoglobin A1c, rates of cesarean delivery, large for gestational age, small for gestational age, neonatal hypoglycemia, and neonatal intensive care unit admission, summarized as mean differences or odds ratios with 95% confidence intervals and 95% prediction intervals. Prespecified subgroup analyses were undertaken by diabetes in pregnancy subtype, including duration of continuous glucose monitoring use (continuous vs intermittent) for large for gestational age. Certainty of evidence was assessed using the Grading of Recommendations, Assessment, Development, and Evaluations framework.

RESULTS

Across diabetes in pregnancy, continuous glucose monitoring (vs self-monitoring of blood glucose) decreased hemoglobin A1c (mean difference, -0.22% [95% confidence interval, -0.37, -0.08]) (7 randomized controlled trials, moderate-certainty evidence). Within diabetes in pregnancy, continuous glucose monitoring use (vs self-monitoring of blood glucose) showed similar but stronger benefits in both type 1 diabetes when used throughout pregnancy (hemoglobin A1c mean difference, -0.18% [95% confidence interval, -0.36, 0.00]; large for gestational age odds ratio, 0.51 [0.28, 0.90]) (1 randomized controlled trial, high-certainty evidence), and gestational diabetes when used intermittently (hemoglobin A1c mean difference, -0.18 [95% confidence interval, -0.33, -0.02]) (5 randomized controlled trials, moderate-certainty evidence) and large for gestational age (odds ratio, 0.46 [0.26, 0.81]) (1 quasi-experimental study, low-certainty evidence), with insufficient data for continuous glucose monitoring benefit in type 2 diabetes. Increased pregnancy %time-in-range (type 1 diabetes) and decreased mean sensor glucose (type 1 diabetes/gestational diabetes) were associated with decreased large for gestational age.

CONCLUSION

Usage of continuous glucose monitoring (vs self-monitoring of blood glucose) reduces hemoglobin A1c and possibly large for gestational age across diabetes in pregnancy. Greatest benefit was evidenced in type 1 diabetes, followed by gestational diabetes, although continuous glucose monitoring duration differed. Mean sensor glucose and pregnancy %time-in-range are important continuous glucose monitoring metrics for reducing large for gestational age.

Use of continuous glucose monitoring and hybrid closed-loop therapy in pregnancy

Continuous glucose monitoring (CGM) has led to a paradigm shift in the management of pregnant women with type 1 diabetes (T1D), with improved glycaemic control, less hypoglycaemia and fewer pregnancy complications. Data on CGM use in pregnant women with type 2 diabetes (T2D) are limited. A large randomized controlled trial (RCT) on CGM use in people with T2D in pregnancy is ongoing. Small studies on CGM use in women with gestational diabetes (GDM) have suggested improved glycaemic control and better qualification when insulin is needed. However, none of these studies was powered to evaluate pregnancy outcomes. Several large RCTs are ongoing in women with GDM. In addition to CGM, other technologies, such as advanced hybrid closed-loop (AHCL) systems have further improved glycaemic management in people with T1D. AHCL therapy adapts insulin delivery via a predictive algorithm integrated with CGM and an insulin pump. A large RCT with the AHCL CamAPS® FX demonstrated a 10% increase in time in range compared to standard insulin therapy in a pregnant population with T1D. Recently, an RCT of an AHCL system not approved for use in pregnancy (780G MiniMed) has also demonstrated additional benefits of AHCL therapy compared to standard insulin therapy, with improved time in range overnight, less hypoglycaemia and improved treatment satisfaction. More evidence is needed on the impact of AHCL therapy on maternal and neonatal outcomes and on which glycaemic targets with CGM should be used in pregnant women with T2D and GDM. We review the current evidence on the use of CGM and AHCL therapy in pregnancy.

Continuous Glucose Monitoring for Diabetes Management During Pregnancy: Evidence, Practical Tips, and Common Pitfalls

Continuous glucose monitoring (CGM) has the potential to revolutionize diabetes management during pregnancy by providing detailed and real-time data to patients and clinicians, overcoming many of the limitations of self-monitoring of blood glucose. Although there are limited data on the role of CGM to improve pregnancy outcomes in patients with type 2 diabetes or gestational diabetes, CGM has been shown to reduce pregnancy complications in patients with type 1 diabetes. Despite the limited data in some populations, given its ease of use and recent U.S. Food and Drug Administration approval with expanding insurance coverage, CGM has gained widespread popularity among pregnant patients with all types of diabetes. It is critical for obstetric clinicians to understand how CGM can be successfully integrated into clinical practice. We present a practical, step-wise approach to CGM data interpretation that can be incorporated into diabetes management during pregnancy and common CGM pitfalls and solutions. Although technology will continue to advance with newer-generation CGM devices and diabetes technology such as automated insulin delivery (not covered here), these key principles form a basic foundation for understanding CGM technology and its utility for pregnant people.

Continuous Glucose Monitoring for Management of Type 2 Diabetes and Perinatal Outcomes

OBJECTIVE

To evaluate the association between continuous glucose monitoring in pregnant people with type 2 diabetes and perinatal outcomes.

METHODS

This was a retrospective cohort study of pregnant people with type 2 diabetes who received prenatal care and delivered singleton, nonanomalous neonates at a single academic tertiary care center from November 1, 2019, to February 28, 2023. The primary outcome was a composite of neonatal morbidity, including hypoglycemia, hyperbilirubinemia, shoulder dystocia, large for gestational age at birth, preterm birth, neonatal intensive care unit (NICU) admission, or perinatal death. Demographics and outcomes were compared by type of monitoring (continuous glucose monitoring vs intermittent self-monitoring of blood glucose), and multivariable logistic regression estimated the association between continuous glucose monitoring use and perinatal outcomes.

RESULTS

Of 360 pregnant people who met the inclusion criteria, 82 (22.7%) used continuous glucose monitoring. The mean gestational age at continuous glucose monitoring initiation was 21.3±6.4 weeks. The use of continuous glucose monitoring was associated with lower odds of the primary composite neonatal morbidity (65.9% continuous glucose monitoring vs 77.0% self-monitoring of blood glucose, adjusted odds ratio [aOR] 0.48, 95% CI, 0.24-0.94). Continuous glucose monitoring use was also associated with lower odds of preterm birth (13.4% vs 25.2%, aOR 0.48, 95% CI, 0.25-0.93) and NICU admission (33.8% vs 47.6%, aOR 0.36, 95% CI, 0.16-0.81).

CONCLUSION

In pregnant people with type 2 diabetes, continuous glucose monitoring use was associated with less neonatal morbidity, fewer preterm births, and fewer NICU admissions.

The use of technology in type 2 diabetes and prediabetes: a narrative review

The increasing incidence of type 2 diabetes, which represents 90% of diabetes cases globally, is a major public health concern. Improved glucose management reduces the risk of vascular complications and mortality; however, only a small proportion of the type 2 diabetes population have blood glucose levels within the recommended treatment targets. In recent years, diabetes technologies have revolutionised the care of people with type 1 diabetes, and it is becoming increasingly evident that people with type 2 diabetes can also benefit from these advances. In this review, we describe the current knowledge regarding the role of technologies for people living with type 2 diabetes and the evidence supporting their use in clinical practice. We conclude that continuous glucose monitoring systems deliver glycaemic benefits for individuals with type 2 diabetes, whether treated with insulin or non-insulin therapy; further data are required to evaluate the role of these systems in those with prediabetes (defined as impaired glucose tolerance and/or impaired fasting glucose and/or HbA1c levels between 39 mmol/mol [5.7%] and 47 mmol/mol [6.4%]). The use of insulin pumps seems to be safe and effective in people with type 2 diabetes, especially in those with an HbA1c significantly above target. Initial results from studies exploring the impact of closed-loop systems in type 2 diabetes are promising. We discuss directions for future research to fully understand the potential benefits of integrating evidence-based technology into care for people living with type 2 diabetes and prediabetes.

Technology advances in diabetes pregnancy: right technology, right person, right time

This review outlines some of the extraordinary recent advances in diabetes technology, which are transforming the management of type 1 diabetes before, during and after pregnancy. It highlights recent improvements associated with use of continuous glucose monitoring (CGM) but acknowledges that neither CGM nor insulin pump therapy are adequate for achieving the pregnancy glucose targets. Furthermore, even hybrid closed-loop (HCL) systems that are clinically effective outside of pregnancy may not confer additional benefits throughout pregnancy. To date, there is only one HCL system, the CamAPS FX, with a strong evidence base for use during pregnancy, suggesting that the pregnancy benefits are HCL system specific. This is in stark contrast to HCL system use outside of pregnancy, where benefits are HCL category specific. The CamAPS FX HCL system has a rapidly adaptive algorithm and lower glucose targets with benefits across all maternal glucose categories, meaning that it is applicable for all women with type 1 diabetes, before and during pregnancy. For women of reproductive years living with type 2 diabetes, the relative merits of using non-insulin pharmacotherapies vs diabetes technology (dipeptidyl peptidase-4 inhibitors, glucagon-like peptide-1 receptor agonists and sodium-glucose cotransporter 2 inhibitors) are unknown. Despite the urgent unmet need and potential benefits, studies of pharmacotherapy and technology use are extremely limited in pregnant women with type 2 diabetes.

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.

Technology and health inequities in diabetes care: How do we widen access to underserved populations and utilize technology to improve outcomes for all?

Digital health technologies are being utilized increasingly in the modern management of diabetes. These include tools such as continuous glucose monitoring systems, connected blood glucose monitoring devices, hybrid closed-loop systems, smart insulin pens, telehealth, and smartphone applications (apps). Although many of these technologies have a solid evidence base, from the perspective of a person living with diabetes, there remain multiple barriers preventing their optimal use, creating a digital divide. In this article, we describe many of the origins of these barriers and offer recommendations on widening access to digital health technologies for underserved populations living with diabetes to improve their health outcomes.

Down-Regulation of CPEB4 Alleviates Preeclampsia through the Inhibition of Ferroptosis by PFKFB3

Gestational diabetes mellitus (GDM) complicated with preeclampsia can lead to polyhydramnios, ketosis. Herein, we explored that CPEB4 in cancer progression of preeclampsia and its underlying mechanism. All the serum samples were collected from patients with preeclampsia. These was the induction of CPEB4 in patients with preeclampsia. The serum of CPEB4 mRNA expression was positive correlation with Proteinuria, systolic blood pressure and diastolic blood pressure in patients. The serum of CPEB4 mRNA expression was also negative correlation with body weight of infant in patients. The serum of CPEB4 mRNA expression also was negative correlation with GPX4 level and GSH activity level in patients. The serum of CPEB4 mRNA expression was positive correlation with iron content in patients. CPEB4 gene inhibited trophoblast cell proliferation. CPEB4 gene promoted trophoblast cell ferroptosis by mitochondrial damage. CPEB4 gene induced PFKFB3 expression by the inhibition of PFKFB3 Ubiquitination. PFKFB3 inhibitor reduced the effects of CPEB4 on cell proliferation and ferroptosis of trophoblast cell. Taken together, the CPEB4 promoted trophoblast cell ferroptosis through mitochondrial damage by the induction of PFKFB3 expression, CPEB4 as an represents a potential therapeutic strategy for the treatment of preeclampsia or various types of GDM.

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.