Continuous Glucose Monitoring, Glycemic Variability, and Excessive Fetal Growth in Pregnancies Complicated by Type 1 Diabetes

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.

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.

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.

Ambulatory Glucose Profile Changes During Pregnancy in Women With Type 1 Diabetes Using Intermittently Scanned Continuous Glucose Monitoring Empowered by Personalized Education

The ambulatory glucose profile is a valuable tool in managing type 1 diabetes during pregnancy. Time in range (TIR) in the third trimester is one of the most significant parameters contributing to good pregnancy outcomes. This study aimed to evaluate the effect of intermittently scanned continuous glucose monitoring (isCGM) empowered by education on glucose dynamics and to predict third trimester TIR. Data were retrospectively analyzed from 38 pregnant patients with type 1 diabetes (mean age 30.4 ± 6.4 years, BMI 23.7 ± 3.7 kg/m2, disease duration 15.4 ± 9.5 years, preconception A1C 6.9 ± 1%) who used a first-generation FreeStyle Libre isCGM system for at least 3 months before conception and had sensor data captured >70% of the time the system was used. Patients received personalized education on diabetes and on minimizing hypoglycemia and hyperglycemia using CGM trend arrows and frequent sensor scanning. This intervention improved glycemic parameters of glucose regulation (TIR, glucose management indicator, and mean glucose), hyperglycemia (time above range), glucose variability (SD and coefficient of variation [%CV]), and scanning frequency, but did not improve parameters of hypoglycemia (time below range and a number of low glucose events). Logistic regression analysis showed that the first trimester %CV and scanning frequency contributed to the third trimester TIR (P <0.01, adjusted R2 0.40). This study suggests that the use of isCGM empowered by personalized education improves glycemic control in pregnant women with type 1 diabetes. Scanning frequency and %CV in the first trimester predicts TIR in the third trimester, which could help clinicians intervene early to improve outcomes.

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.

Association Between HbA1c Levels on Adverse Pregnancy Outcomes During Pregnancy in Patients With Type 1 Diabetes

CONTEXT

Despite optimization of metabolic balance during pregnancy in type 1 diabetes (T1D), maternal-fetal complications remain higher than in the background population.

OBJECTIVE

We examined whether there is an association between glycated hemoglobin (HbA1c) levels and these complications.

METHODS

Retrospective study of pregnancies in 678 T1D subjects at Lille Hospital (1997-2019). The association between variations in HbA1c levels and complications was examined. The composite criterion (CC) was defined as having at least 1 of the following complications: prematurity, pre-eclampsia, large for gestational age (LGA), small for gestational age (SGA), or cesarean section.

RESULTS

Among the 678 births, median preconception HbA1c was 7.2% (55 mmol/mol), 361 were LGA (56%), 29 were SGA (4.5%), and 504 were births without preterm delivery (76.1%). The CC occurred in 81.8%. Higher HbA1c during the first trimester was associated with the CC (OR 1.04; 95% CI 1.02-1.06 per 0.1% increase; P < .001). Higher HbA1c during the third trimester was associated with the CC (OR 1.07; 95% CI 1.03-1.10 per 0.1% increase; P < .001). The group defined by a first trimester Hba1c >6.5% (48 mmol/mol) and a third trimester HbA1c <6% was associated with an increased rate of the CC (OR 2.81; 95% CI 1.01-7.86) and an increased rate of LGA (OR 2.20; 95% CI 1.01- 4.78).

CONCLUSION

Elevated HbA1c is associated with maternal-fetal complications. Despite optimization of metabolic balance during the third trimester, for patients with early glycemic imbalance the risk of LGA persists.

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.

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.

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.

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).

A novel classification of glucose profile in pregnancy based on continuous glucose monitoring data

AIM

To investigate the glucose profile of women with and without gestational diabetes mellitus (GDM) by simultaneously analyzing several factors of continuous glucose monitoring (CGM) data.

METHODS

CGM was conducted for 2 weeks in the second trimester of pregnant women whose random blood glucose level was ≥100 mg/dl. A 75-g oral glucose tolerance test was performed around day 7, and the index of hyperglycemia, relative hypoglycemia, and indices of glucose variability were extracted from CGM data. Unsupervised hierarchical clustering was performed to categorize glucose profiles of the participants.

RESULTS

CGM data were obtained from 29 women. Glucose profiles were categorized into three clusters: low glucose levels with less glucose variability group (L group, n = 7); moderate glucose levels with moderate-to-high glucose variability group (M group, n = 18); and high glucose levels with high glucose variability group (H group, n = 4). The waveforms of the glucose profiles were very different among the three groups. Women with GDM tended to be more frequent in the H group than in the M and L groups (75.0%, 16.7%, and 14.3%, respectively; p = 0.053). Maternal age was significantly higher and the proportion of multiparous women was significantly larger in the H group compared to L group (p = 0.002 and 0.015, respectively).

CONCLUSIONS

A comprehensive analysis of CGM data could help us extract a subgroup of women with characteristics of GDM.

Does Birthweight Represent Imprinting for Life? Preliminary Findings from the Level and Timing of Diabetic Hyperglycemia in Utero: Transgenerational Effect on Adult Morbidity (TEAM) Study

Women with pre-gestational diabetes have a high rate of large for gestational age (LGA) babies compared to women without diabetes. In particular, there is a high rate of asymmetric LGA defined as ponderal index (PI) > 90th percentile for gestational age. We examined the association of birth weight and PI, with body mass index (BMI) and obesity status in adulthood, in a cohort of offspring of women with pre-gestational diabetes. The women participated in the Diabetes in Pregnancy (DiP) study at the University of Cincinnati from 1978 to 1995. The offspring of these women are the cohort participating in an observational study being conducted at Cincinnati Children’s Hospital Medical Center. Once located, the offspring were invited to come in for a one-day clinic visit to assess anthropometrics, and their metabolic, renal and cardiovascular status. Linear and logistic regression was used to assess the association between birth weight and PI with current BMI. We report on 107 offspring. A statistically significant association was found between offspring current BMI with birth PI (β = 1.89, 95% CI 0.40–3.38), and between offspring current obesity status and birth asymmetric LGA (aOR = 2.44, 95% CI 1.01–5.82). This is consistent with in utero “metabolic programming”.

Dietary intakes of women with Type 1 diabetes before and during pregnancy: a pre-specified secondary subgroup analysis among CONCEPTT participants

AIM

To describe the dietary intakes of women with Type 1 diabetes before and during pregnancy.

METHODS

This was a pre-specified subgroup analysis of CONCEPTT involving 63 women planning pregnancy and 93 pregnant women from 14 sites in England, Scotland and Ireland. Two hundred and forty-six 3-day food diaries (104 planning pregnancy, 142 pregnant) were matched to data source and food reference codes, and analysed using dietary software. Participants were informed that food diaries would be de-identified and used only for research purposes.

RESULTS

Mean (sd) daily energy intake was 1588 (346) kcal and 1673 (384) kcal in women planning pregnancy and pregnant women respectively. Total carbohydrate intake was consistent with dietary guideline recommendations [180 (52) g planning pregnancy, 198 (54) g pregnant], but non-recommended sources (e.g. sugars, preserves, confectionery, biscuits, cakes) contributed to 46% of total daily carbohydrate intake. Fat consumption exceeded guideline recommendations [70 (21) g planning pregnancy, 72 (21) g pregnant]. Fibre [15.5 (5.3) g planning pregnancy, 15.4 (5.1) g pregnant], fruit and vegetable intakes [3.5 (2.2) and 3.1 (1.8) serves/day] were inadequate. Twelve women planning pregnancy (19%) and 24 pregnant women (26%) did not meet micronutrient requirements.

CONCLUSIONS

The diets of pregnant women from England, Scotland and Ireland are characterized by high fat, low fibre and poor-quality carbohydrate intakes. Fruit and vegetable consumption is inadequate, with one in four women at risk of micronutrient deficiencies. Further research is needed to optimize maternal nutrition for glycaemic control and for maternal and offspring health.

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.

Pregnancy in Patients with Type One Diabetes Mellitus Treated with Continuous Subcutaneous Insulin Infusion-Preconception Basal Insulin Dose as a Potential Risk Factor for Fetal Overgrowth?

Despite widespread use of technology, type one diabetes mellitus (T1DM) is still a great clinical challenge during pregnancy. This study aims to assess how prenatal variables of T1DM patients using continuous subcutaneous insulin infusion (CSII) influence pregnancy outcomes. We performed a retrospective study of 35 patients with T1DM treated with CSII during pregnancy. Alterable preconception variables (A1C, body mass index, basal and bolus insulin dose) were analysed as possible contributors to birth weight and large-for-gestational-age (LGA) prevalence. Inclusion criteria were presence of T1DM for more than two years, A1C < 7.4% and treatment with CSII for at least three months prior to conception. The preconception basal insulin dose and A1C had a significant correlation to the neonatal birth weight (p = 0.01, r = 0.4 and p = 0.04, r = 0.3, respectively) and were significant in regression analysis together contributing 22% of the variance in birth weight percentiles (sig = 0.17, R square = 0.22). Prevalence of LGA was 46%. Women who had LGA neonates also had a higher preconception basal insulin dose compared to women with non-LGA neonates (26 ± 9 vs. 18 ± 7 IU (international units), p = 0.01). The LGA group had a higher preconception A1C, but it did not reach statistical significance (6.5 ± 0.5% vs. 6.2 ± 0.9%, respectively, p = 0.2). Women with T1DM treated with CSII who had unregulated glycaemia and more basal insulin were at greater risk for development of LGA neonates.

Insulin Therapy and Diabetic Pregnancy

BACKGROUND

A good metabolic control before conception and throughout pregnancy with diabetes decreases the risk of short- and long-term adverse outcomes of the mothers and their offsprings. Insulin treatment remains the gold standard treatment recommended for any type of diabetes. New technologies including new insulins and insulin analogues, continuous subcutaneous insulin infusion without and with sensors, the low-glucose predictive suspension function, and closed-loop systems that persistently and automatically self-adjust according to patients' continuous glucose monitoring readings have expanded the offer to clinicians for achieving tight glucose control.

AREAS OF UNCERTAINTY

Unsafe effects of insulin and insulin analogues in pregnancy with diabetes could be linked with changes in insulin immunogenicity, teratogenicity, and mitogenicity. Second-generation insulin analogues need to be tested and proven. Effectiveness and safety of new insulin delivery systems in real life of diabetic women in pregnancy need further confirmations.

SOURCES

MEDLINE, EMBASE, Web of Science, Cochrane Library, randomized controlled trials, systematic review and meta-analysis, observational prospective and retrospective studies, case series reports for the most recent insulin analogues, published in English impacted journals, and consensus statements from scientific societies I excluded 60 from 221 papers as not suitable for the purpose of the subject.

RESULTS

Subcutaneous insulin infusion can be safely used during pregnancy and delivery of well-trained women. Sensors are increasingly accurate tools that improve the efficacy and safety of integrated systems' functioning. Continuous glucose monitoring provides metrics ("time in range" time in "hypoglycemia" and in "hyperglycemia," glucose variability, average glucose levels in different time intervals) used as a guide to diabetes management; these new metrics are object of discussion in special populations. Randomized controlled trials have shown that sensor-augmented pump therapy improves pregnancy outcomes in women with type 1 diabetes. Closed-loop insulin delivery provides better glycemic control than sensor-augmented pump therapy during pregnancy, before, and after delivery.

CONCLUSION

Second-generation insulin analogues and newer insulin infusion systems that automatically self-adjust according to patients continuous glucose monitor readings are important tools improving the treatment and quality of life of these women. Multi-institutional and disciplinary teams are working to develop and evaluate a pregnancy-specific artificial pancreas.

Continuous glucose monitoring in pregnant women with type 1 diabetes: an observational cohort study of 186 pregnancies

AIMS/HYPOTHESIS

The aim of this study was to analyse patterns of continuous glucose monitoring (CGM) data for associations with large for gestational age (LGA) infants and an adverse neonatal composite outcome (NCO) in pregnancies in women with type 1 diabetes.

METHODS

This was an observational cohort study of 186 pregnant women with type 1 diabetes in Sweden. The interstitial glucose readings from 92 real-time (rt) CGM and 94 intermittently viewed (i) CGM devices were used to calculate mean glucose, SD, CV%, time spent in target range (3.5-7.8 mmol/l), mean amplitude of glucose excursions and also high and low blood glucose indices (HBGI and LBGI, respectively). Electronic records provided information on maternal demographics and neonatal outcomes. Associations between CGM indices and neonatal outcomes were analysed by stepwise logistic regression analysis adjusted for confounders.

RESULTS

The number of infants born LGA was similar in rtCGM and iCGM users (52% vs 53%). In the combined group, elevated mean glucose levels in the second and the third trimester were significantly associated with LGA (OR 1.53, 95% CI 1.12, 2.08, and OR 1.57, 95% CI 1.12, 2.19, respectively). Furthermore, a high percentage of time in target in the second and the third trimester was associated with lower risk of LGA (OR 0.96, 95% CI 0.94, 0.99 and OR 0.97, 95% CI 0.95, 1.00, respectively). The same associations were found for mean glucose and for time in target and the risk of NCO in all trimesters. SD was significantly associated with LGA in the second trimester and with NCO in the third trimester. Glucose patterns did not differ between rtCGM and iCGM users except that rtCGM users had lower LBGI and spent less time below target.

CONCLUSIONS/INTERPRETATION

Higher mean glucose levels, higher SD and less time in target range were associated with increased risk of LGA and NCO. Despite the use of CGM throughout pregnancy, the day-to-day glucose control was not optimal and the incidence of LGA remained high.