Effects of continuous glucose monitoring on maternal and neonatal outcomes in perinatal women with diabetes: A systematic review and meta-analysis of randomized controlled trials

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.

Consensus Considerations and Good Practice Points for Use of Continuous Glucose Monitoring Systems in Hospital Settings

Continuous glucose monitoring (CGM) systems provide frequent glucose measurements in interstitial fluid and have been used widely in ambulatory settings for diabetes management. During the coronavirus disease 2019 (COVID-19) pandemic, regulators in the U.S. and Canada temporarily allowed for CGM systems to be used in hospitals with the aim of reducing health care professional COVID-19 exposure and limiting use of personal protective equipment. As such, studies on hospital CGM system use have been possible. With improved sensor accuracy, there is increased interest in CGM usage for diabetes management in hospitals. Laboratorians and health care professionals must determine how to integrate CGM usage into practice. The aim of this consensus guidance document is to provide an update on the application of CGM systems in hospital, with insights and opinions from laboratory medicine, endocrinology, and nursing.

All Children Deserve to Be Safe, Mothers Too: Evidence and Rationale Supporting Continuous Glucose Monitoring Use in Gestational Diabetes Within the Medicaid Population

Gestational diabetes mellitus (GDM) is a common metabolic disease of pregnancy that threatens the health of several million women and their offspring. The highest prevalence of GDM is seen in women of low socioeconomic status. Women with GDM are at increased risk of adverse maternal outcomes, including increased rates of Cesarean section delivery, preeclampsia, perineal tears, and postpartum hemorrhage. However, of even greater concern is the increased risk to the fetus and long-term health of the child due to elevated glycemia during pregnancy. Although the use of continuous glucose monitoring (CGM) has been shown to reduce the incidence of maternal and fetal complications in pregnant women with type 1 diabetes and type 2 diabetes, most state Medicaid programs do not cover CGM for women with GDM. This article reviews current statistics relevant to the incidence and costs of GDM among Medicaid beneficiaries, summarizes key findings from pregnancy studies using CGM, and presents a rationale for expanding and standardizing CGM coverage for GDM within state Medicaid populations.

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.

Multigenerational diabetes mellitus

Gestational diabetes (GDM) changes the maternal metabolic and uterine environment, thus increasing the risk of short- and long-term adverse outcomes for both mother and child. Children of mothers who have GDM during their pregnancy are more likely to develop Type 2 Diabetes (T2D), early-onset cardiovascular disease and GDM when they themselves become pregnant, perpetuating a multigenerational increased risk of metabolic disease. The negative effect of GDM is exacerbated by maternal obesity, which induces a greater derangement of fetal adipogenesis and growth. Multiple factors, including genetic, epigenetic and metabolic, which interact with lifestyle factors and the environment, are likely to contribute to the development of GDM. Genetic factors are particularly important, with 30% of women with GDM having at least one parent with T2D. Fetal epigenetic modifications occur in response to maternal GDM, and may mediate both multi- and transgenerational risk. Changes to the maternal metabolome in GDM are primarily related to fatty acid oxidation, inflammation and insulin resistance. These might be effective early biomarkers allowing the identification of women at risk of GDM prior to the development of hyperglycaemia. The impact of the intra-uterine environment on the developing fetus, "developmental programming", has a multisystem effect, but its influence on adipogenesis is particularly important as it will determine baseline insulin sensitivity, and the response to future metabolic challenges. Identifying the critical window of metabolic development and developing effective interventions are key to our ability to improve population metabolic health.

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

OBJECTIVE

This study aimed to assess whether continuous glucose monitor use in type 2 diabetes mellitus in pregnancy is associated with improved perinatal outcomes.

DATA SOURCES

We searched Ovid MEDLINE, Scopus, ClinicalTrials.gov, and Cochrane library from inception through May 9, 2022.

STUDY ELIGIBILITY CRITERIA

We included all studies that compared continuous glucose monitor use with fingerstick glucose monitoring in women with type 2 diabetes mellitus.

METHODS

The initial search yielded 2463 unique citations that were screened in Covidence by 2 independent reviewers. Study types included randomized controlled trials, cohort studies, and cross-sectional studies. Our outcomes of interest were macrosomia or large-for-gestational-age infants, hemoglobin A1c, cesarean delivery, hypertensive disorders of pregnancy including preeclampsia, gestational age at delivery, and neonatal hypoglycemia.

RESULTS

Three randomized controlled trials met the inclusion criteria. We performed random-effects meta-analyses of estimates from 2 studies without risk of significant bias and reported summary adjusted odds ratios and 95% confidence intervals. Meta-analysis of 56 women with continuous glucose monitor use and 53 control women without continuous glucose monitor use showed that there was no difference in the incidence of large-for-gestational-age infants between continuous glucose monitor users and standard-of-care controls (odds ratio, 0.78; 95% confidence interval, 0.34-1.78) with an I2 of 0%. In addition, there was no difference in the development of preeclampsia between continuous glucose monitor users and standard-of-care controls (odds ratio, 1.63; 95% confidence interval, 0.34-7.22) with an I2 of 0%.

CONCLUSION

Continuous glucose monitor use was not associated with improved perinatal outcomes as assessed by large-for-gestational-age infants and preeclampsia. This review is limited by the small amount of data available for this population, and further research is needed.