Review of Studies on Insulin Pump Use During Pregnancy
Stewart et al. (2016) conducted a randomized crossover trial to evaluate the efficacy and safety of an AHCL system in pregnant women with T1DM. Sixteen participants completed two 4-week intervention phases: one with conventional CSII combined with CGM, and the other with an AHCL system that autonomously adjusted basal insulin delivery based on sensor glucose levels. Use of the closed-loop system significantly increased time in the pregnancy-specific glycaemic target range (3.5–7.8 mmol/L), particularly during the night (75% vs. 59%;
p<0.001), without increasing the incidence of hypoglycaemia. Overall TIR improved from 61% with standard CSII to 69% with AHCL (
p=0.002), accompanied by a reduction in time spent in hyperglycaemia. No episodes of severe hypoglycaemia or diabetic ketoacidosis were reported. Participants subjectively reported improved sleep quality and reduced anxiety during the closed-loop treatment phase. The study concluded that AHCL insulin delivery is safe and enhances glycaemic control during pregnancy, particularly in the overnight period, underscoring its potential role in the management of T1DM in pregnant women [
11].
The CONCEPTT trial (Continuous Glucose Monitoring in Women with Type 1 Diabetes in Pregnancy), conducted by Feig et al. (2017), was a pivotal multicentre, international, randomized controlled trial investigating the impact of real-time CGM on glycaemic control and pregnancy outcomes in women with T1DM. The study enrolled 325 women, including 215 who were already pregnant at the time of randomization. Pregnant participants were assigned to either real-time CGM or conventional SMBG, while continuing intensive insulin therapy via MDI or insulin pumps. The primary endpoint was the change in HbA1c from baseline to 34 weeks’ gestation. Although the CGM group demonstrated only a modest reduction in HbA1c compared to the SMBG group (mean difference −0.2%, p=0.02), CGM use resulted in a significantly greater percentage of TIR spent within the pregnancy-specific target glycaemic range (3.5–7.8 mmol/L), reduced time in hyperglycaemia, and no increase in hypoglycaemia.
Importantly, CGM was associated with improved neonatal outcomes. The incidence of LGA neonates was significantly lower in the CGM group compared to SMBG (53% vs. 69%,
p=0.02), as were the rates of neonatal hypoglycaemia and neonatal NICU admissions exceeding 24 hours (27% vs. 43%,
p=0.01). The authors concluded that CGM use in pregnant women with T1DM improves neonatal outcomes and confers modest benefits in maternal glycaemic control, supporting its integration into routine antenatal diabetes management [
3].
A retrospective observational study assessing the impact of combining CSII with CGM on glycaemic control and pregnancy outcomes in women with pregestational T1DM was conducted by
Lason et al. (2021). The analysis included 81 singleton pregnancies from 109 women treated between 2016 and 2017, stratified into three groups: CSII+CGM, CSII alone, and MDI. Women using CSII with CGM achieved significantly better glycaemic control throughout pregnancy and postpartum compared to the other groups. In this group, mean HbA1c remained consistently low: 5.3% in the first and second trimesters, 5.2% in the third, and 5.5% postpartum. Despite superior metabolic control, no significant differences were found between groups in obstetric outcomes, including gestational age at delivery, rates of preterm birth, or neonatal birth weight. Macrosomia remained prevalent (~20%) even among women with optimal glycaemic control. The study concluded that CGM combined with CSII, particularly with advanced safety algorithms (AID), significantly improves maternal glycaemic outcomes. However, the persistent incidence of macrosomia suggests that factors beyond maternal glycaemia may contribute to foetal overgrowth in T1DM pregnancies [
12].
A retrospective observational study evaluating the effectiveness of SAP therapy in pregnant women with T1DM was conducted by
Imafuku et al. (2023). The study compared maternal metabolic control and neonatal outcomes between women treated with SAP and those using MDI in combination with CGM. A total of 41 pregnant women with T1DM were included: 21 in the SAP group and 20 in the MDI+CGM group. Assessed outcomes included mean glucose levels, TIR (3.5–7.8 mmol/L), incidence of LGA neonates, neonatal birth weight, and frequency of maternal hypoglycaemia. The SAP group demonstrated superior glycaemic control, with significantly lower mean glucose levels and a higher proportion of TIR during the second and third trimesters. Moreover, SAP therapy was associated with a significantly lower incidence of LGA infants and fewer hypoglycaemic episodes compared to the MDI+CGM group. These findings support the clinical benefit of SAP therapy in optimizing metabolic control and reducing the risk of adverse neonatal outcomes in pregnant women with T1DM [
2].
The
AiDAPT study (Lee TTM et al.,
2023) was a multicentre, randomized controlled trial designed to assess the efficacy and safety of AID systems in pregnant women with T1DM. A total of 124 women were enrolled early in pregnancy, at a mean gestational age of 11 weeks, and randomly assigned to receive either an AID system (CamAPS FX closed-loop technology) or conventional SAP therapy without automation. The primary outcome was the percentage of time spent within the pregnancy-specific glycaemic target range (3.5–7.8 mmol/L) from 16 to 36 weeks of gestation. Women using the AID system achieved significantly better glycaemic control, spending on average 14 percentage points more TIR compared to the SAP group. The AID group also exhibited lower mean glucose concentrations and reduced time in hyperglycaemia, with no significant increase in time spent in hypoglycaemia. Although the trial was not powered to detect differences in maternal or neonatal clinical outcomes, there were no significant differences between the groups in the incidence of serious adverse events. The findings demonstrate that AID systems are both effective and safe for use in pregnancy, offering substantial improvements in glycaemic control. The authors concluded that AID should be considered a preferred therapeutic option for pregnant women with T1DM to optimize maternal glucose levels and potentially improve pregnancy outcomes [
6,
13].
Rankin et al. (2023) examined healthcare professionals’ perspectives on implementing AHCL systems in pregnant women with T1DM. As AID technologies become more widely available, understanding the practical and systemic barriers to their integration into antenatal care is essential. The study involved semi-structured interviews with 29 clinicians—including diabetologists, obstetricians, diabetes specialist nurses, and midwives—across multiple NHS centres in the UK. Thematic analysis revealed overall support for AHCL use in pregnancy, citing benefits such as improved glycaemic control, reduced hypoglycaemia risk, and decreased psychological burden. However, several concerns were raised, including the complexity of the technology, increased workload for clinical staff, the need for specialised training, and disparities in access between centres. Participants highlighted the importance of multidisciplinary education, clear care pathways, and robust patient support systems. System-level factors, including funding, device availability, and workflow integration, were identified as critical to successful implementation. The authors concluded that while there is strong clinical enthusiasm for AHCL use in pregnancy, effective rollout requires coordinated planning, resource allocation, and efforts to ensure equitable access across healthcare settings [
14].
As part of a qualitative sub-study embedded in the AiDAPT randomized controlled trial,
Lawton et al. (2023) explored the experiences of pregnant women with T1DM using AHCL systems. Semi-structured interviews were conducted with 26 women who used the CamAPS FX system during pregnancy. Participants reported a marked reduction in the mental and emotional burden of diabetes management. Automated insulin adjustments provided a sense of safety—particularly overnight—and contributed to improved sleep, greater confidence, and a feeling of normalcy. Women also noted enhanced glycaemic control and increased day-to-day flexibility. Despite these benefits, some challenges were identified, including device wearability issues, occasional technical difficulties, and the continued need for user input for meal bolusing. The study concluded that AHCL systems offer significant psychological and practical benefits for pregnant women with T1DM. The authors emphasized the importance of incorporating patient experiences into clinical care models and service planning to support equitable and patient-centred implementation of this technology in routine antenatal diabetes management [
15].
According to
NICE (2023), HCL therapy should be offered to adults with T1DM who have an HbA1c level of 7.5% (58 mmol/mol or higher) despite optimized use of CSII or CGM, or to those experiencing disabling hypoglycaemia. In contrast, children, adolescents, and women who are pregnant or planning pregnancy are eligible for HCL therapy regardless of their current HbA1c level. These recommendations are supported by clinical trial data and real-world evidence demonstrating improvements in glycaemic control, including reductions in HbA1c and TAR, as well as increased time in the target glucose range (3.5–7.8 mmol/L). Additionally, patients report reduced psychological distress and fear of hypoglycaemia when using these systems. HCL systems are classified by NICE as a technology class rather than by brand; however, commercially available systems such as the Medtronic MiniMed 780G, Tandem t: slim X2 with Control-IQ, and CamAPS FX fall within the scope of the recommendation [
16].
The CRISTAL study (Benhalima et al.,
2024) was a multicentre, open-label, randomized controlled trial evaluating the efficacy and safety of AHCL insulin therapy in pregnant women with T1DM. A total of 124 women (≥18 years, ≤13+6 weeks’ gestation, HbA1c ≤9%) were randomized 1:1 to receive either AHCL therapy with the MiniMed 780G system or standard insulin therapy (MDI or CSII, with or without CGM) across nine Belgian centres. Participants were followed until delivery. The primary endpoint—TIR (3.5–7.8 mmol/L) from 14 to 34 weeks’ gestation—was significantly higher in the AHCL group (68.4%) compared to standard care (55.6%), with an adjusted mean difference of 12.8 percentage points (95% CI: 7.8–17.8;
p<0.0001). AHCL users also had lower mean glucose levels, reduced time in hyperglycaemia, and significantly lower HbA1c at 34 weeks (6.2% vs 6.6%), with no increase in hypoglycaemia. Neonatal outcomes favoured the AHCL group, with lower rates of LGA infants (31% vs 41%) and neonatal hypoglycaemia (33% vs 50%), though differences were not statistically significant. No cases of severe hypoglycaemia or diabetic ketoacidosis were reported. The study concluded that AHCL therapy during pregnancy significantly improves glycaemic control without increasing adverse events, supporting its use as a preferred treatment strategy in pregnant women with T1DM [
1].
The CRISTAL study was the first randomized trial to evaluate off-label use of the MiniMed 780G system in automated mode during pregnancy. While no significant improvement in daytime TIR was observed, the AHCL system significantly increased overnight TIR and reduced the risk of hypoglycaemia, which was associated with improved glycaemic variability, reduced hypoglycaemia unawareness, and greater maternal satisfaction. Given that hypoglycaemia is a major barrier to tight glycaemic control during pregnancy, this finding is clinically important. The study also confirmed the safety of AHCL use during pregnancy. In comparison, the AiDAPT study demonstrated a significantly greater overall TIR (+10.5%) with the CamAPS FX system versus standard care. However, baseline characteristics differed: women in AiDAPT had higher initial HbA1c (7.7% vs 6.5%), lower baseline TIR and TBR, and most control participants were on BBT, unlike CRISTAL, where 77.5% used insulin pumps in manual mode. Furthermore, the CamAPS system targeted a lower glucose threshold for automated delivery (4.4 mmol/L) compared to MiniMed 780G (5.5 mmol/L), which may explain the greater glycaemic improvements observed in AiDAPT [
1].
The CopenFast study (Nørgaard et al.,
2023) was a single-centre, open-label, randomized controlled trial comparing faster-acting insulin aspart with conventional insulin aspart in pregnant women with pregestational diabetes (type 1 or type 2). A total of 208 women (133 with T1DM, 75 with T2DM) were enrolled before 14 weeks’ gestation and randomized 1:1 to receive either insulin as part of a basal-bolus regimen throughout pregnancy and 6 weeks postpartum. The primary outcome was 1-hour postprandial glucose, which was significantly lower with faster aspart (mean difference –0.37 mmol/L;
p=0.015). HbA1c, TIR, insulin requirements, and maternal weight gain were similar between groups. Neonatal outcomes, including rates of LGA infants (30% in both groups) and neonatal hypoglycaemia, did not differ significantly. These findings support its use as a safe and effective prandial insulin option during pregnancy in women with diabetes [
17].