A Randomized Trial of Closed-Loop Insulin Delivery Postpartum in Type 1 Diabetes

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.

Mixed Methods Randomized Controlled Trial Comparing Quality of Life for Pregnant Women With Type 1 Diabetes Using Hybrid Closed-Loop to Sensor-Augmented Pump Therapy

OBJECTIVE

Type 1 diabetes in pregnancy is challenging. This study explores how assisted hybrid closed-loop therapy (HCL) versus sensor-augmented pump therapy (SAPT) impacts quality of life in pregnancy.

METHODS

We interviewed 22 of 24 participants randomized to HCL or SAPT in the Pregnancy Intervention with a Closed-Loop System study. Participants completed questionnaires about hypoglycemia fear and device satisfaction and trust.

RESULTS

Quality of life was similar among women with type 1 diabetes using HCL (n = 12) and SAPT (n = 12) throughout pregnancy and early postpartum. Hypoglycemia fear was not statistically different between groups but improved in the HCL group in the second trimester versus baseline. Glucose monitoring satisfaction and trust increased during pregnancy in the HCL group but decreased in the SAPT group. Women trusted their mode of insulin delivery despite stress and frustration with fluctuating glucose and risks of hyperglycemia to their fetuses. Women who preferred less involvement with their management preferred HCL, whereas those desiring more involvement preferred SAPT.

CONCLUSION

These similarities demonstrate that open communication is needed between provider and patient to determine perceived benefits versus burdens of HCL use in pregnancy, especially in the United States where available HCL systems lack pregnancy-specific algorithms and Food and Drug Administration approval for pregnancy use.

Efficacy of automated insulin delivery systems in people with type 1 diabetes: a systematic review and network meta-analysis of outpatient randomised controlled trials

Background

The comparative efficacy of automated insulin delivery (AID) systems and other treatment options for type 1 diabetes, accounting for the certainty of evidence (CoE), is unknown.

Methods

We searched PubMed, EMBASE, the Cochrane Central Register of Controlled Trials and ClinicalTrials.gov and included outpatient randomised controlled trials (RCTs) published until January 8, 2025, in people with type 1 diabetes with a three-week or longer intervention of AID systems (PROSPERO registration number: CRD42023395492). We performed pairwise and network meta-analyses and used the Risk of Bias tool 2 and the Grading of Recommendations Assessment, Development and Evaluation methods to determine the CoE for each outcome.

Findings

A total of 46 studies involving seven insulin treatment options and 4113 participants were included, of which 29 and 17 had low and moderate risks of bias, respectively. The intervention AID systems, including the hybrid closed-loop (HCL), advanced HCL (AHCL) and full closed-loop (FCL) systems, were evaluated in 20, 25 and 1 studies, respectively. The network meta-analysis did not indicate global inconsistencies but did indicate global publication bias for all glycaemic outcomes. The CoE varied between very low and high, depending on the treatment and outcome under consideration. Compared with pump therapy, the percentage of time in the range 70-180 mg/dl was greater with AID use (HCL: 19.7% [95% confidence interval 13.2%; 26.1%], moderate CoE; AHCL: 24.1% [18.2%; 29.9%], moderate CoE; FCL: 25.5% [11.1%; 39.9%], high CoE). Compared with pump therapy, the percentage of time above 180 mg/dl and 250 mg/dl was lower with AHCL, on average, by 19.6% (14.0%; 25.1%), moderate CoE, and 14.8% (8.8%; 20.8%), moderate CoE, respectively. The CoE was very uncertain regarding the overall effect of AID systems on the percentage of time below 70 mg/dl and 54 mg/dl and the HbA1c.

Interpretation

AID systems improve glycaemic outcomes to varying degrees and with varying CoE.

Funding

German Federal Ministry of Education and Research (BMBF; grant 01KG2203).

Automated Insulin Delivery in Pregnancies Complicated by Type 1 Diabetes

Automated insulin delivery (AID) systems adapt insulin delivery via a predictive algorithm integrated with continuous glucose monitoring and an insulin pump. Automated insulin delivery has become standard of care for glycemic management of people with type 1 diabetes (T1D) outside pregnancy, leading to improvements in time in range, with lower risk for hypoglycemia and improved treatment satisfaction. The use of AID facilitates optimal preconception care, thus more women of reproductive age are becoming pregnant while using AID. The effectiveness and safety in pregnant populations of using AID systems with algorithms for non-pregnant populations may be impacted by requirements for lower glucose targets and existence of increased insulin resistance during gestation. The CamAPS FX is the only AID system approved for use in pregnancy. A large randomized controlled trial (RCT) with this AID system demonstrated a 10.5% increase in time in pregnancy range (an additional 2.5 hours/day) compared with standard insulin therapy in pregnant women with T1D with a baseline glycated hemoglobin A1c (HbA1c) ≥48 mmol/mol (6.5%). A RCT of AID not approved for use in pregnancy (MiniMed 780G) has also demonstrated some benefits of AID compared with standard insulin therapy with improved time in pregnancy range overnight (24 minutes), less hypoglycemia, and improved treatment satisfaction. There is also increasing evidence that AID can be safely continued during delivery and postpartum, while maintaining glycemic goals with lower risk for hypoglycemia. More AID systems are needed with flexible glucose targets in the pregnancy range and possibly with algorithms that better adapt to changing insulin requirements. More evidence is needed on the impact of AID on maternal and neonatal outcomes. We review the current evidence on the use of AID in pregnancy and postpartum.

Automated insulin delivery during the first 6 months postpartum (AiDAPT): a prespecified extension study

BACKGROUND

Clinical guidelines in the UK and elsewhere do not specifically address hybrid closed loop (HCL) use in the postpartum period when the demands of caring for a newborn are paramount. Our aim was to evaluate the safety and efficacy of HCL use during the first 6 months postpartum compared with standard care.

METHODS

In this prespecified extension to a multicentre, randomised controlled trial, pregnant women with type 1 diabetes at nine UK sites were followed up for 6 months postpartum. Eligible participants (AiDAPT participants recruited after the implementation of the postpartum protocol amendment approval, those still pregnant or within six months of delivery at the time of amendment implementation and still using HCL or continuous glucose monitoring [CGM] therapy) continued their randomly assigned treatment, either standard insulin therapy with CGM or HCL therapy (CamAPS FX system version 0.3.1, CamDiab, Cambridge, UK). Participants were randomised in a 1:1 ratio with stratification by clinical site using randomly permuted block sizes of 2 or 4. The primary outcome was the between-group difference in percentage time in range ([TIR] 3·9-10·0 mmol/L [70-180mg/dL]), measured during the periods of month 0 up to 3, months 3 to 6, and over 6 months postpartum. The study is registered at ClinicalTrials.gov (ISRCTN56898625) and is complete.

FINDINGS

Of the 124 AiDAPT trial participants, 66 (53%) were ineligible for inclusion in the postpartum extension, and 57 participants consented to continue their treatment per original random allocation. The mean age was 31 years (SD 4), and all participants had early pregnancy HbA1c 59·4 mmol/mol (SD 10·5 [7·6% SD 1·0%]). In the 6 months postpartum, mean time with glucose levels within the target range was higher in the HCL group compared with the standard care group (72% [SD 12%] vs 54% [17%]), with an adjusted treatment difference of 15% (95% CI 7 to 22). Results for hyperglycaemia (>10·0 mmol/L) and mean CGM glucose also favoured HCL (-14% [95% CI -23% to -6%] and -1·3 mmol/L [-2·3 to -0·3], respectively). Hypoglycaemia rates were low, with no between-group differences (2·4% vs 2·6%). There were no treatment effect changes depending on postpartum period (0 up to 3 months vs 3 to 6 months) and no unanticipated safety problems.

INTERPRETATION

Participants in the HCL group maintained 70% TIR during the first 6 months postpartum, supporting continued use of HCL rather than standard insulin therapy for people with diabetes once they have given birth.

FUNDING

National Institute for Health Research, Juvenile Diabetes Research Foundation, and Diabetes Research & Wellness Foundation. CGM devices were provided by Dexcom at a discounted price.

Automated insulin delivery in pregnant women with type 1 diabetes: a systematic review and meta-analysis

AIM

The outcomes of automated insulin delivery (AID) systems in pregnant women with type 1 diabetes (T1D) have not been systematically evaluated. This study aims to evaluate the efficacy and safety of AID in pregnancy.

MATERIAL AND METHODS

Literature searches were conducted until July 5, 2024, on Embase, PubMed, Cochrane Library, and ClinicalTrials.gov website. We included clinical trials and observational studies evaluating AID systems in T1D pregnant individuals. Time in the target range (TIR, 3.5-7.8 mmol/L) was the primary outcome. Secondary outcomes included time below range (TBR, < 3.5 mmol/L), time above range (TAR, > 7.8 mmol/L), and maternal and neonatal outcomes.

RESULTS

Eighteen studies (550 participants) were included. Compared with standard care, AID did not improve 24-h TIR (mean differences [MD] 3.56%, 95% CI - 0.60 to 7.72). However, the overnight TIR increased by 10.05% (95% CI 6.57 to 13.53). The association between AID and decreased TBR (MD - 0.90%, 95% CI - 1.60 to - 0.20) was found, but not with deceased TAR. Only 7 of the 17 studies achieved the goal of a 24-h TIR above 70%. Additionally, the maternal and neonatal outcomes were comparable between AID and standard care, and AID might reduce maternal weight gain (MD - 2.54 kg, 95% CI - 3.96 to - 1.11).

CONCLUSIONS

AID did not exhibit favourable TIR when compared to standard care. However, AID could increase overnight TIR and decrease TBR. Available evidence indicates that employing AID to meet the target of a 24-h TIR above 70% remains challenging.

15. Management of Diabetes in Pregnancy: Standards of Care in Diabetes-2025

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

Women's and Partners' Experiences With a Closed-loop Insulin Delivery System to Manage Type 1 Diabetes in the Postpartum Period

OBJECTIVES

Closed-loop insulin delivery has the potential to offer women with type 1 diabetes a break from intense diabetes self-care efforts postpartum. Our aim in this study was to explore the views and opinions of hybrid closed-loop users and their partners in the first 24 weeks postpartum.

METHODS

This qualitative study was embedded in a controlled study of women with type 1 diabetes randomized to closed-loop insulin delivery (MiniMed 670G or 770G; Medtronic, Minneapolis, Minnesota, United States) or sensor-augmented pump use for 1 to 11 weeks 6 days postpartum, with all on closed-loop delivery from 12 to 24 weeks postpartum. Semistructured interviews were conducted with 16 study participants and their partners at 12 and 24 weeks postpartum. Thematic analyses were used to examine participants' and partners' experiences.

RESULTS

Participants' positive perceptions of closed-loop use related to reduced hypoglycemia, in contrast to previous experiences with nonautomated insulin delivery. These perceptions were balanced against frustrations with the system, allowing blood glucose levels to be higher than desired. Closed-loop use did not influence infant feeding choice, but infant feeding and care impacted participants' diabetes management. Partners expressed uncertainty about the closed loop taking away control from participants who were highly skilled with diabetes self-management.

CONCLUSIONS

Participants reported that closed-loop insulin delivery resulted in less time spent in hypoglycemia when compared with the previously used nonautomated delivery. However, participants desired a greater understanding of the workings of the closed-loop algorithm. Our study provides potential users with realistic expectations about the experience with the MiniMed 670G or 770G closed-loop system in the postpartum period.

Glucose Control During Labour and Delivery in Type 1 Diabetes - An Update on Current Evidence

PURPOSE OF REVIEW

To provide an update on diabetes management during labour and delivery in women with type 1 diabetes with focus on appropriate insulin administration, carbohydrate supply and use of diabetes technology to support safe delivery and neonatal well-being.

RECENT FINDINGS

During active labour and elective cesarean section capillary blood glucose monitoring or continuous glucose monitoring at least hourly is recommended. Infusion with isotonic (5%) glucose can be given with adjustable infusion rate to address maternal carbohydrate requirements and to prevent maternal hypoglycemia. Subcutaneous insulin administration with multiple injections or insulin pump therapy is considered at least as safe and efficient as intravenous administration to obtain tight glycemic targets. Automated insulin delivery via insulin pump can be continued during labour and delivery. Diabetes management during labour and delivery involves intensive glucose monitoring, adequate insulin administration and carbohydrate administration to support safe delivery and neonatal well-being.

Automated Insulin Delivery for Pregnant Women With Type 1 Diabetes: Where Do We Stand?

Automated insulin delivery (AID) systems mimic an artificial pancreas via a predictive algorithm integrated with continuous glucose monitoring (CGM) and an insulin pump, thereby providing AID. Outside of pregnancy, AID has led to a paradigm shift in the management of people with type 1 diabetes (T1D), leading to improvements in glycemic control with lower risk for hypoglycemia and improved quality of life. As the use of AID in clinical practice is increasing, the number of women of reproductive age becoming pregnant while using AID is also expected to increase. The requirement for lower glucose targets than outside of pregnancy and for frequent adjustments of insulin doses during pregnancy may impact the effectiveness and safety of AID when using algorithms for non-pregnant populations with T1D. Currently, the CamAPS® FX is the only AID approved for use in pregnancy. A recent randomized controlled trial (RCT) with CamAPS® FX demonstrated a 10% increase in time in range in a pregnant population with T1D and a baseline glycated hemoglobin (HbA1c) ≥ 48 mmol/mol (6.5%). Off-label use of AID not approved for pregnancy are currently also being evaluated in ongoing RCTs. More evidence is needed on the impact of AID on maternal and neonatal outcomes. We review the current evidence on the use of AID in pregnancy and provide an overview of the completed and ongoing RCTs evaluating AID in pregnancy. In addition, we discuss the advantages and challenges of the use of current AID in pregnancy and future directions for research.

Advanced Hybrid Closed-Loop Therapy Compared With Standard Insulin Therapy Intrapartum and Early Postpartum in Women With Type 1 Diabetes: A Secondary Observational Analysis From the CRISTAL Randomized Controlled Trial

OBJECTIVE

To determine efficacy and safety of intrapartum and early postpartum advanced hybrid closed-loop (AHCL) therapy compared with standard insulin therapy in pregnant women with type 1 diabetes (T1D).

RESEARCH DESIGN AND METHODS

CRISTAL was a double-arm, open-label, randomized controlled trial performed in Belgium and the Netherlands that assigned 95 pregnant participants with T1D 1:1 to a MiniMed 780G AHCL system (n = 46) or standard insulin therapy (n = 49). This prespecified, secondary observational analysis focused on differences in glycemic control and safety outcomes between participants from the original AHCL group who continued AHCL intrapartum (n = 27) and/or early postpartum (n = 37, until hospital discharge) and those from the original standard insulin therapy group using standard insulin therapy intrapartum (n = 45) and/or early postpartum (n = 34).

RESULTS

Of the 43 and 46 participants in the AHCL and standard insulin therapy groups, respectively, completing the trial, 27 (62.8%) in the AHCL group continued AHCL and 45 in the standard insulin therapy group (97.8%) continued standard insulin therapy intrapartum. Compared with standard insulin therapy, intrapartum AHCL was associated with more time in range 3.5-7.8 mmol/L (71.5 ± 17.7% vs. 63.1 ± 17.0%, P = 0.030) and numerically lower time above range >7.8 mmol/L (27.3 ± 17.4% vs. 35.3 ± 17.5%, P = 0.054), without increases in time below range <3.5 mmol/L (1.1 ± 2.4% vs. 1.5 ± 2.3%, P = 0.146). Early postpartum, 37 (86.0%) participants randomized to AHCL continued AHCL, with a median increase in insulin-to-carbohydrate ratios of 67% (interquartile range -14 to 126). Similar tight glycemic control (3.9-10.0 mmol/L: 86.8 ± 6.7% vs. 83.8 ± 8.1%, P = 0.124) was observed with AHCL versus standard insulin therapy. No severe hypoglycemia or diabetic ketoacidosis was reported in either group.

CONCLUSIONS

AHCL is effective in maintaining tight glycemic control intrapartum and early postpartum and can be safely continued during periods of rapidly changing insulin requirements.

Glycaemic patterns during breastfeeding with postpartum use of closed-loop insulin delivery in women with type 1 diabetes

AIMS/HYPOTHESIS

This study aimed to describe the relationship between breastfeeding episodes and maternal glucose levels, and to assess whether this differs with closed-loop vs open-loop (sensor-augmented pump) insulin therapy.

METHODS

Infant-feeding diaries were collected at 6 weeks, 12 weeks and 24 weeks postpartum in a trial of postpartum closed-loop use in 18 women with type 1 diabetes. Continuous glucose monitoring (CGM) data were used to identify maternal glucose patterns within the 3 h of breastfeeding episodes. Generalised mixed models adjusted for breastfeeding episodes in the same woman, repeat breastfeeding episodes, carbohydrate intake, infant age at time of feeding and early pregnancy HbA1c. This was a secondary analysis of data collected during a randomised trial (ClinicalTrials.gov registration no. NCT04420728).

RESULTS

CGM glucose remained above 3.9 mmol/l in the 3 h post-breastfeeding for 93% (397/427) of breastfeeding episodes. There was an overall decrease in glucose at nighttime within 3 h of breastfeeding (1.1 mmol l-1 h-1 decrease on average; p=0.009). A decrease in nighttime glucose was observed with open-loop therapy (1.2 ± 0.5 mmol/l) but was blunted with closed-loop therapy (0.4 ± 0.3 mmol/l; p<0.01, open-loop vs closed-loop).

CONCLUSIONS/INTERPRETATION

There is a small decrease in glucose after nighttime breastfeeding that usually does not result in maternal hypoglycaemia; this appears to be blunted with the use of closed-loop therapy.

Updates in the Management of Type 1 Diabetes in Pregnancy

The care of pregnant individuals with type 1 diabetes mellitus has experienced significant advancements in recent years. Preconception counseling has re-emerged as a core dimension of management. Continuous glucose monitoring plays an increasingly useful and beneficial role in gestational glycemic monitoring, a practice informed by improved maternofetal outcomes. While studies have not shown that continuous subcutaneous insulin infusion is superior to multiple daily injections of insulin for glycemic control, recent work has signaled that hybrid closed-loop systems with pregnancy-specific targets could meaningfully improve glycemic control and potentially ameliorate maternofetal outcomes while reducing self-care burden.