Glucose variability in diabetic pregnancy

Continuous Glucose Monitoring Feedback in the Subsequent Development of Gestational Diabetes: A Pilot, Randomized, Controlled Trial in Pregnant Women

OBJECTIVE

 This study evaluated the effects of receiving glucose feedback from continuous glucose monitoring (CGM) by intermittent scanning (unblinded group), and CGM with masked feedback (blinded group) in the subsequent development of gestational diabetes mellitus (GDM).

STUDY DESIGN

 This was a prospective, single-center, pilot, randomized controlled trial including n = 206 pregnant women in the first trimester of pregnancy with no prior diagnosis of type 1 or type 2 diabetes. The participants were randomized into the unblinded group or blinded group and wore the CGM in the first trimester of pregnancy (9-13 weeks), the second trimester of pregnancy (18-23 weeks), and late-second to early-third trimester (24-31 weeks). The primary outcome was GDM rate as diagnosed by the 75-g oral glucose tolerance test (OGTT) at 24 to 28 weeks.

RESULTS

 Over 47 months, 206 pregnant women were enrolled at 9 to 13 weeks. The unblinded group had a higher prevalence of women who developed GDM (21.5 vs. 14.9%; p > 0.05), compared to the blinded group. In the unblinded group compared to the blinded group, plasma glucose values were higher at 1 hour (median 7.7 [interquartile range {IQR}: 6.3-9.2] vs. 7.5 [6.3-8.7]) and 2 hours (6.3 [5.8-7.7] vs. 6.2 [5.3-7.2]), but lower at 0 hour (4.2 [4.0-4.5] vs. 4.3 [4.1-4.6]; p > 0.05). All these differences were not statistically significant.

CONCLUSION

 Glucose feedback from CGM wear in the first to the third trimester of pregnancy without personalized patient education failed to alter GDM rate.

KEY POINTS

· Continuous glucose monitoring (CGM) is feasible for use in pregnant women.. · No significant difference in gestational diabetes rates with or without CGM feedback.. · Future clinical trials should incorporate CGM education and personalized guidance to enhance study 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.

Glycemic variability in diagnosis of gestational diabetes as predictor of pharmacological treatment

INTRODUCTION

To establish whether glycemic variability (GV) parameters used when gestational diabetes mellitus (GDM) has been diagnosed could help predict the probability that a patient will need pharmacological treatment, and to analyze the link of these parameters to the development of maternal-fetal complications.

MATERIALS AND METHODS

A prospective study of 87 women with GDM who underwent retrospective continuous glucose monitoring (CGM) for six days between weeks 26 and 32 of gestation, following diagnosis. The mean glycemia levels and GV variables were analyzed together with their link to maternal-fetal complications, and the need for pharmacological treatment. ROC (receiver operating characteristic) curves were developed to determine validity to detect the need for pharmacological treatment.

RESULTS

Patients with higher mean glycemia (p < 0.001) and continuous overlapping of net glycemic action in a period of n-hours (CONGAn) (p = 0.001) required pharmacological treatment. The ROC curves showed cut-off points of 98.81 mg/dL for mean glycemia, and 86.70 mg/dL for CONGAn, with 83.3% sensitivity and 67.8% specificity for both parameters. No relation between the GV parameters and development of maternal-fetal complications was observed.

CONCLUSIONS

The use of CGM, once GDM is diagnosed, enables us to identify those patients who would benefit from closer monitoring during gestation, and facilitate a speedier take-up of pharmacological treatment. However, prospective studies involving a higher number of patients are needed, as well as a cost assessment for recommending the use of CGM following GDM diagnosis.

Continuous Glucose Monitoring in Pregnancy

Diabetes mellitus in pregnancy is associated with adverse maternal and neonatal outcomes. Optimal glycemic control is associated with improved outcomes. Continuous glucose monitoring is a less invasive alternative to blood glucose measurements. Two types of continuous glucose monitoring are available in the market: real time and intermittently scanned. Continuous glucose monitoring is gaining popularity and is now recommended by some societies for glucose monitoring in pregnant women. In this review, we discuss the differences between the two types of continuous glucose monitoring, optimal treatment goals, and whether there is an improvement in maternal or neonatal outcomes.

Correlations between parameters of glycaemic variability and foetal growth, neonatal hypoglycaemia and hyperbilirubinemia in women with gestational diabetes

The diagnosis of gestational diabetes mellitus (GDM) is important to prevent maternal and neonatal complications. This study aimed to investigate the feasibility of parameters of glycaemic variability to predict neonatal complications in women with GDM. A retrospective study was conducted on pregnant women tested positive at the oral glucose tolerance test (OGTT) during 16-18 or 24-28 weeks of gestation. Glycaemic measures were extracted from patients' glucometers and expanded to obtain parameters of glycaemic variability. Data on pregnancy outcomes were obtained from clinical folders. Descriptive group-level analysis was used to assess trends in glycaemic measures and foetal outcomes. Twelve patients were included and analysed, accounting for 111 weeks of observations. The analysis of trends in parameters of glycaemic variability showed spikes of glycaemic mean, high blood glucose index and J-index at 30-31 weeks of gestation for cases with foetal macrosomia, defined as foetal growth >90° percentile, neonatal hypoglycaemia and hyperbilirubinemia. Specific trends in parameters of glycaemic variability observed at third trimester correlate with foetal outcomes. Further research is awaited to provide evidence that monitoring of glycaemic variability trends could be more clinically informative and useful than standard glycaemic checks to manage women with GDM at delivery.

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.

Hypoglycemia in Prospective Multicenter Study of Pregnancies with Pre-Existing Type 1 Diabetes on Sensor-Augmented Pump Therapy: The LOIS-P Study

Background: Pregnancies in type 1 diabetes are high risk, and data in the United States are limited regarding continuous glucose monitoring (CGM)-based hypoglycemia throughout pregnancy while on sensor-augmented insulin pump therapy. Materials and Methods: Pregnant women with type 1 diabetes in the LOIS-P Study (Longitudinal Observation of Insulin use and glucose Sensor metrics in Pregnant women with type 1 diabetes using continuous glucose monitors and insulin pumps) were enrolled before 17 weeks gestation at three U.S. centers and we used their personal insulin pump and a study Dexcom G6 CGM. We analyzed data of 25 pregnant women for CGM hypoglycemia based on international consensus guidelines for percentage time <63 and 54 mg/dL, hypoglycemic events and prolonged hypoglycemia events for 24-h, daytime, and overnight periods, and severe hypoglycemia (SH) episodes. Results: For a 24-h period, biweekly median percentage of time <63 mg/dL ranged from 0.8% at biweek 4-5 to 3.7% at biweek 14-15 with high variability throughout pregnancy. Median percentage of time <63 and 54 mg/dL was higher overnight than daytime (P < 0.01). Hypoglycemic events occurred throughout the pregnancy, ranged 1-4 events per 2 weeks, significantly decreased after the 20th week, and occurred predominantly during daytime (P < 0.01). For overnight period, hypoglycemia and events were more concentrated from 12 to 3 am. Seven prolonged hypoglycemia events without any associated SH occurred in four participants (16%), primarily overnight. Three participants experienced a single episode of SH. Conclusions: Our results suggest a higher overall risk of hypoglycemia throughout pregnancy during the overnight period with continued daytime risk of hypoglycemic events in pregnancies complicated by type 1 diabetes.

Feasibility of Closed-Loop Insulin Delivery with a Pregnancy-Specific Zone Model Predictive Control Algorithm

Objective: Evaluating the feasibility of closed-loop insulin delivery with a zone model predictive control (zone-MPC) algorithm designed for pregnancy complicated by type 1 diabetes (T1D). Research Design and Methods: Pregnant women with T1D from 14 to 32 weeks gestation already using continuous glucose monitor (CGM) augmented pump therapy were enrolled in a 2-day multicenter supervised outpatient study evaluating pregnancy-specific zone-MPC based closed-loop control (CLC) with the interoperable artificial pancreas system (iAPS) running on an unlocked smartphone. Meals and activities were unrestricted. The primary outcome was the CGM percentage of time between 63 and 140 mg/dL compared with participants' 1-week run-in period. Early (2-h) postprandial glucose control was also evaluated. Results: Eleven participants completed the study (age: 30.6 ± 4.1 years; gestational age: 20.7 ± 3.5 weeks; weight: 76.5 ± 15.3 kg; hemoglobin A1c: 5.6% ± 0.5% at enrollment). No serious adverse events occurred. Compared with the 1-week run-in, there was an increased percentage of time in 63-140 mg/dL during supervised CLC (CLC: 81.5%, run-in: 64%, P = 0.007) with less time >140 mg/dL (CLC: 16.5%, run-in: 30.8%, P = 0.029) and time <63 mg/dL (CLC: 2.0%, run-in:5.2%, P = 0.039). There was also less time <54 mg/dL (CLC: 0.7%, run-in:1.6%, P = 0.030) and >180 mg/dL (CLC: 4.9%, run-in: 13.1%, P = 0.032). Overnight glucose control was comparable, except for less time >250 mg/dL (CLC: 0%, run-in:3.9%, P = 0.030) and lower glucose standard deviation (CLC: 23.8 mg/dL, run-in:42.8 mg/dL, P = 0.007) during CLC. Conclusion: In this pilot study, use of the pregnancy-specific zone-MPC was feasible in pregnant women with T1D. Although the duration of our study was short and the number of participants was small, our findings add to the limited data available on the use of CLC systems during pregnancy (NCT04492566).

Glycaemia dynamics in gestational diabetes mellitus

Pregnant women may develop gestational diabetes mellitus (GDM), a disease of pregnancy characterised by maternal and fetal hyperglycaemia with hazardous consequences to the mother, the fetus, and the newborn. Maternal hyperglycaemia in GDM results in fetoplacental endothelial dysfunction. GDM-harmful effects result from chronic and short periods of hyperglycaemia. Thus, it is determinant to keep glycaemia within physiological ranges avoiding short but repetitive periods of hyper or hypoglycaemia. The variation of glycaemia over time is defined as 'glycaemia dynamics'. The latter concept regards with a variety of mechanisms and environmental conditions leading to blood glucose handling. In this review we summarized the different metrics for glycaemia dynamics derived from quantitative, plane distribution, amplitude, score values, variability estimation, and time series analysis. The potential application of the derived metrics from self-monitoring of blood glucose (SMBG) and continuous glucose monitoring (CGM) in the potential alterations of pregnancy outcome in GDM are discussed.

Time in range measurements for hyperglycemia management during pregnancy

The prevalence of adverse pregnancy outcomes associated with poor glycemic control are increasing. Accordingly, effective blood glucose monitoring during pregnancy has become a subject of intense interest. Continuous glucose monitoring (CGM) displays dynamic changes in blood glucose by using probes to measure glucose concentration in the interstitial fluid, and the rapid development of CGM has enabled the investigation of time in range (TIR) in the glucose target range as a new parameter to evaluate blood glucose. International guidelines have identified TIR as an important blood glucose assessment method for pregnant patients with type 1 diabetes mellitus that overcomes the limitations of conventional gestational blood glucose monitoring, better reflects fluctuation in blood glucose during pregnancy, and effectively improves maternal and neonatal outcomes. However, there is little clinical evidence for the use of TIR in pregnant women with gestational diabetes mellitus and those with pre-pregnant type 2 diabetes mellitus. TIR is expected to become a critical indicator of blood glucose control and management in hyperglycemic pregnant patients. We review the research progress of TIR to help clinicians understand the field of blood glucose monitoring in pregnant women with hyperglycemia.

Glucose variability as the risk factor of preeclampsia in pregnant patients with type 1 diabetes mellitus

OBJECTIVE

To analyze glucose variability and investigate its role as a predictor for preeclampsia development in pregnant women with type 1 diabetes mellitus (T1DM) with various insulin therapy regimens.

METHODS

A total of 200 pregnant women with T1DM were included in the study. A hundred women used continuous subcutaneous insulin infusion (CSII), and the rest of the group was administered with multiple daily insulin injections (MDI). Continuous glucose monitoring (CGM), index calculation of glucose variability (MAGE, MODD, CONGA, and CV), assessment of preeclampsia frequency and severity were conducted.

RESULTS

The work results show the link between the severity rate of preeclampsia and the duration of T1DM as well as the level of HbA1c before and during pregnancy. The rate of preeclampsia in the group of women, using CSII comprises 26.8% of cases that appear less than in the group of those, administered with MDI that is 46.6% (χ² = 5.45; р < .05). A negative correlation is defined between pathological glucose variability and gestational age when preeclampsia occurs. A negative correlation was also revealed between MODD, CV, and the time for the detection of preeclampsia: r = -0.30, r = -0.24, respectively. The study illustrates the correlation obtained between preeclampsia and glucose variability and the value of MAGE, MODD, CV, and SD. Preeclampsia development is affected by the duration of hyperglycemic conditions in the third trimester of pregnancy. The data in the group of women using MDI marks the early development of preeclampsia on the 33.0 [32-34] week of pregnancy compared to the group of women practicing CSII on 35.5 [33-36] week of pregnancy (Z = 5.4; p < .001). The increase of risk of preeclampsia development is proved in pregnant patients with T1DM when the hyperglycemic condition lasts more than 25% of a 24-h period according to the rate of CGM and measurements of glucose variability MODD > 1.07 and CONGA > 3.39.

CONCLUSION

Comprehensive evaluation of the glycemic profile while using CGM revealed a correlation between pathological glucose variability and the frequency and severity of preeclampsia thus proving the benefits of CSII in pregnant patients with T1DM to perform glycemic targets and decrease glucose variability, which eventually led to the decrease of preeclampsia frequency in this group of women.

Glycemic Variability in Early Pregnancy May Predict a Subsequent Diagnosis of Gestational Diabetes

PURPOSE

This study examined the prospective association between CGM-derived glycemic variability (GV) and glycemic control (GC) parameters in the first and second trimester, with subsequent diagnosis of GDM in the early third trimester.

METHODS

In a longitudinal observational study, 60 study participants in the first trimester (9-13 weeks' gestation), and 53 participants (18-23 weeks' gestation) in the second trimester of pregnancy had CGM data extracted after a minimum of 8 days' wear time (up to 14 days). At 24-31 weeks' gestation, participants underwent a 75 g, 2-hour oral glucose-tolerance test as per IADPSG criteria to diagnose GDM. GV parameters examined in both first and second trimesters were mean amplitude of glycemic excursion (MAGE), standard deviation (SD), mean glucose, and coefficient of variation (CV). GC parameters measured were J-Index and percentage of time spent in glucose target ranges.

RESULTS

The first trimester SD and MAGE were significantly higher in participants subsequently diagnosed with GDM (SD adjusted median 1.31 [interquartile range 1.2-1.3] mmol/L; MAGE 3.26 [3.2-3.3] mmol/L) than those who were not (SD 1.01 [0.9-1.0] mmol/L, MAGE 2.59 [2.4-2.6] mmol/L; p<0.05). Similarly, second trimester SD and MAGE were also significantly higher in participants subsequently diagnosed with GDM (SD 1.35 [1.3-1.4] mmol/L; MAGE 3.32 (3.31-3.41) mmol/L) than those who were not (SD 0.99 [0.98-1.01] mmol/L, MAGE 2.42 [2.42-2.55] mmol/L; p<0.05). Associations between SD and MAGE with GDM outcomes were adjusted for prepregnancy BMI and ethnicity. There were nonsignificant trends of higher J-Index scores in the first and second trimester, higher CV in the first trimester only, and higher mean in the second trimester only in participants diagnosed with GDM. Other study parameters measured were not significantly different between groups (p>0.003).

CONCLUSION

Our study suggests the potential value of CGM-derived SD and MAGE in early pregnancy as potential predictors of subsequent GDM diagnosis.

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.

Exploratory Analysis of Glycemic Control and Variability Over Gestation Among Pregnant Women with Type 1 Diabetes

In exploratory analyses, we evaluated glycemic variability (GV) and gestational outcomes in pregnant women (n = 28) with type 1 diabetes (T1D). Gestational age at delivery was higher for women with lower glycemic measures, including estimated HbA1c (eHbA1c) (0.14% decrease in HbA1c per 1-week greater gestational age, P = 0.0035), mean sensor glucose (-3.9 mg/dL P = 0.0039), time spent >140 mg/dL (-3.1%, P = 0.0029), and higher time in range (TIR) of 63-140 mg/dL (3.2%, P = 0.0029). Third trimester measured HbA1c was significantly associated with gestational age at delivery (P = 0.0081). Preeclampsia was associated with less TIR in first (50.5% vs. 69.9%, P = 0.0034) and second trimesters (47.1% vs. 66.7%, P = 0.0025), but not with measured HbA1c. There were significant differences in other markers of GV (continuous overall net glycemic action, high blood glucose index, J-index, mean amplitude of glycemic excursions) with infant birth weight and gestational age at delivery. Thus, multiple markers of glycemia and GV were associated with gestational health outcomes in T1D pregnancies in this pilot study. Clinical Trial Registration number: NCT02556554.

Efficacy of flash glucose monitoring in pregnant women with poorly controlled pregestational diabetes (FlashMom): A randomized pilot study

BACKGROUND AND AIMS

Good glycemic control is crucial to reduce the risk of adverse pregnancy outcomes. Our aim was to evaluate the efficacy of Flash Glucose Monitoring (FGM) on glucose control in women with pregestational diabetes.

METHODS AND RESULTS

Forty women with inadequately controlled type 1 (T1D, n = 34) and type 2 (T2D, n = 6) diabetes at conception were randomly assigned to two arms: the Flash Glucose group (FG, n = 21) using FGM, and the control group (CG, n = 19) using self-monitoring of blood glucose (SMBG). Glycated hemoglobin (HbA1c, %), time in (TIR), below (TBR) and above (TAR) range, glucose variability as well as the occurrence of maternal and neonatal adverse outcomes, were evaluated. HbA1c decreased significantly (p < 0.01) and similarly (-0.65 ± 0.7 vs. -0.67 ± 0.8 for FG and CG, respectively; p = 0.89) in both groups during pregnancy. HbA1c reduction was positively associated with the number of daily FGM scans (p < 0.01). TBR (12.1 ± 2.0% vs. 19.6 ± 3.9%, p = 0.04) and the mean of the daily serum glucose difference (MODD) index (59.1 ± 5.4 vs. 77.7 ± 4.6, p = 0.02) were significantly lower in FG at second trimester. The rates of perinatal adverse outcomes were not different in the two studied groups.

CONCLUSIONS

In women with pregestational diabetes, FGM and SMBG had similar efficacy on glucose control during pregnancy. FGM showed additional advantages in terms of TBR and glucose variability. Achievement of good metabolic results depended on the adequate use of glucose sensor.

REGISTRATION

At ClinicalTrials.gov as NCT04666818 on December 14, 2020.

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).

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.

Care of Infants Born to Women with Diabetes

PURPOSE OF REVIEW

Infants of women with diabetes are at risk for specific morbidities including congenital anomalies, abnormalities of fetal growth, neonatal hypoglycemia, electrolyte abnormalities, polycythemia, hyperbilirubinemia, and respiratory distress syndrome. Recent studies have shed light on long-term outcomes of these infants and presented advances in treatment. The purpose of this review is to outline the most common neonatal morbidities affecting infants of women with diabetes, the pathophysiology and prevalence of these conditions, and contemporary approaches to treatment.

RECENT FINDINGS

Recent investigative findings have led to advances in treatment approaches for these infants, particularly regarding risks of neonatal hypoglycemia. Optimizing maternal glycemic control during pregnancy is imperative to improving infant outcomes. However, on a population level, maternal diabetes still poses significant risks to the infant. Timely and appropriate treatment of infants of women with diabetes is imperative to decrease short- and long-term morbidity.

The association between novel glucose indices in parturients with type 1 diabetes mellitus and clinically significant neonatal hypoglycemia

The aim of this study was to determine the association between glucose control indices of parturient with type 1 diabetes (T1DM), treated with an insulin pump and utilizing continuous glucose monitoring (CGM), and clinically significant neonatal hypoglycemia. This was a retrospective cohort study which included 37 pregnant women with T1DM. All women were followed at a single tertiary center and had available CGM data. The association between maternal glucose indices before delivery and the risk for neonatal hypoglycemia requiring IV glucose (clinically significant hypoglycemia) was assessed using logistic regression. Mothers to neonates that experienced clinically significant hypoglycemia had a higher glucose standard deviation (SD) before delivery than did mothers to neonates who did not (25.5 ± 13 mg/dL vs. 14.7 ± 6.7 mg/dl respectively; p = .008). This association persisted after adjustment for maternal age, maternal pregestational body mass index (BMI), gestational age at delivery, neonatal birth weight, large for gestational age (LGA) and gender. This study demonstrates an association between high maternal glucose standard deviation before delivery and the risk for clinically significant neonatal hypoglycemia. Larger studies are needed to confirm these results and further explore the role of intrapartum glucose variability in the prediction and prevention of significant neonatal hypoglycemia.

Evaluation of Glycaemic Control, Glucose Variability and Hypoglycaemia on Long-Term Continuous Subcutaneous Infusion vs. Multiple Daily Injections: Observational Study in Pregnancies With Pre-Existing Type 1 Diabetes

INTRODUCTION

We evaluated the effectiveness of long-term continuous subcutaneous insulin infusion (CSII) compared with multiple daily insulin (MDI) injections for glycaemic control and variability, hypoglycaemic episodes and maternal/neonatal outcomes in pregnant women with pre-existing type 1 diabetes (pT1D).

METHODS

Our observational cohort study included 128 consecutive pregnant women with pT1D, who were treated from 1 January 2010 to 31 December 2017. Of 128 participants, 48 were on CSII and 80 were on MDI. Glycaemic control was determined by glycated haemoglobin (HbA1c) (captured in preconception and each trimester of pregnancy). Glucose variability (GV) was expressed as the coefficient of variation (CV) [calculated from self-monitoring of blood glucose (SMBG) values], and hypoglycaemia was defined as glucose values < 3.9 mmol/l. The data on maternal and neonatal outcomes were collected from obstetrical records.

RESULTS

Duration of the treatment was 8.8 ± 5.3 years in the CSII and 12.6 ± 8.0 years in the MDI group. The CSII lowered HbA1c in preconception (7.1 ± 0.1 vs. 7.9 ± 0.2%, p = 0.03) and the first (6.9 ± 0.1 vs. 7.7 ± 0.2%, p = 0.02), second (6.6 ± 0.1 vs. 7.2 ± 0.1%, p = 0.003) and third (6.5 ± 0.1 vs. 6.8 ± 0.1%, p = 0.02) trimesters significantly better than MDI. Significantly lower CV was observed only for fasting glycaemia in the first trimester (17.1 vs 28.4%, p < 0.001) in favour of CSII. Moreover, the CSII group had significantly lower mean hypoglycaemic episodes/week/patient only during the first trimester (2.0 ± 1.7 vs 4.8 ± 1.5, p < 0.01). In early pregnancy, the majority of women on CSII had less hypoglycaemia than on MDI (0-3: 79.1 vs. 29.1%; 4-6: 18.8 vs. 65.8%; ≥ 7: 2.1 vs. 5.1%, p < 0.01, respectively). We found no difference in the incidence of adverse maternal/neonatal outcomes.

CONCLUSIONS

Treatment with CSII resulted in a favourable reduction of HbA1c in the preconception period and each trimester in pregnancy. Moreover, long-term CSII treatment demonstrated more stable metabolic control with less GV of fasting glycaemia and fewer hypoglyacemic episodes only during early pregnancy.

Effect of High Versus Low Carbohydrate Intake in the Morning on Glycemic Variability and Glycemic Control Measured by Continuous Blood Glucose Monitoring in Women with Gestational Diabetes Mellitus-A Randomized Crossover Study

Carbohydrate is the macronutrient that has the greatest impact on blood glucose response. Limited data are available on how carbohydrate distribution throughout the day affects blood glucose in women with gestational diabetes mellitus (GDM). We aimed to assess how a high-carbohydrate morning-intake (HCM) versus a low-carbohydrate-morning-intake (LCM), affect glycemic variability and glucose control. In this randomized crossover study continuous glucose monitoring (CGM) was performed in 12 women with diet treated GDM (75 g, 2-h OGTT ≥ 8.5 mmol/L), who went through 2 × 3 days of HCM and LCM. A within-subject-analysis showed a significantly higher mean amplitude of glucose excursions (MAGE) (0.7 mmol/L, p = 0.004) and coefficient of variation (CV) (5.1%, p = 0.01) when comparing HCM with LCM, whereas a significantly lower mean glucose (MG) (-0.3 mmol/L, p = 0.002) and fasting blood glucose (FBG) were found (-0.4 mmol/L, p = 0.01) on the HCM diet compared to the LCM diet. In addition, insulin resistance, expressed as Homeostatic Model Assessment for Insulin Resistance (HOMA-IR), decreased significantly during HCM. Results indicate that a carbohydrate distribution of 50% in the morning favors lower blood glucose and improvement in insulin sensitivity in women with GDM, but in contrary gives a higher glycemic variability.

A Review of Research Progress on Glycemic Variability and Gestational Diabetes

Gestational diabetes mellitus (GDM) is associated with many adverse obstetric outcomes and neonatal outcomes, including preeclampsia, Cesarean section, and macrosomia. Active screening and early diabetes control can reduce the occurrence of adverse outcomes. Glycosylated hemoglobin (HbA1c) only reflects average blood glucose levels, but not glycemic variability (GV). Studies have shown that GV can cause a series of adverse reactions, and good control of GV can reduce the incidence of adverse pregnancy outcomes in patients with GDM. In order to provide clinicians with a better basis for diagnosis and treatment, this study reviewed the measurement, evaluation, and control of GV, the importance of GV for patients with GDM, and correlations between GV and maternal and neonatal outcomes.

Prepregnancy care in women with type 1 diabetes improves HbA1c and glucose variability without worsening hypoglycaemia time and awareness: Glycaemic variability during prepregnancy care

AIMS

To evaluate the impact of a prepregnancy care (PPC) programme, beyond HbA_1c, on hypoglycaemia awareness and glycaemic variability (GV).

METHODS

Prospective pilot study. We selected women with Type 1 diabetes who initiated a PPC programme with normal hypoglycaemia awareness (n = 24). Hypoglycaemia awareness, hypoglycaemic events and GV derived from masked-continuous glucose monitoring were evaluated in the first visit and within 2 weeks after pregnancy confirmation.

RESULTS

The duration was 16.5 ± 13.0 months. HbA_1c significantly decreased (-0.8 ± 0.7; p < 0.001). The Clarke score increased (0[0-1] vs. 1[0-2] points, p = 0.164), 2 out of 24 were reclassified as having impaired awareness of hypoglycaemia and 2 presented severe hypoglycaemia. GV decreased: standard deviation (p = 0.008), coefficient of variation (p = 0.021), mean amplitude of glycaemic excursions (p = 0.007), average daily risk range (p < 0.001), J-index (p = 0.010), high blood glucose index (HBGI) (p = 0.004), continuous overall net glycaemic action (CONGA) (p = 0.018), mean of daily differences (p = 0.045) and glycaemic risk assessment diabetes equation (p = 0.012). Final HbA_1c was associated with baseline J-index, CONGA and HBGI (β = 0.535, β = 0.466, β = 0.534, respectively; p < 0.05).

CONCLUSIONS

A PPC programme improved HbA_1c as well as GV with no significant impact on hypoglycaemia awareness. Moreover, GV could help to identify women less likely to achieve glycaemic targets. Larger studies are needed to confirm these results.

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.

Application and Utility of Continuous Glucose Monitoring in Pregnancy: A Systematic Review

Background: In the past decade, continuous glucose monitoring (CGM) has been proven to have similar accuracy to self-monitoring of blood glucose (SMBG) and yet provides better therapy optimization and detects trends in glucose values due to higher frequency of testing. Even though the feasibility and utility of CGM has been proven successfully in Type 1 and 2 diabetes, there is a lack of knowledge of its application and effectiveness in pregnancy, especially in gestational diabetes mellitus (GDM). In this review, we aimed to summarize and evaluate the updated scientific evidence on the application of CGM in pregnancies complicated with GDM. Methods: A search using keywords related to CGM and GDM on PubMed was conducted and articles were filtered based on full text, year of publication (Jan 1998-Dec 2018), human subject studies, and written in English. Reviews and duplicate articles were removed. A final total of 29 articles were included in this review. Results: In terms of maternal and fetal outcomes, inconsistent evidence was reported. Among GDM patients using CGM and SMBG, two randomized controlled trials (RCTs) found no significant differences in macrosomia, birth weight (BW), and gestational age (GA) at delivery between these two groups, while one prospective cohort found a lower incidence of cesarean section and macrosomia in CGM use subjects. Furthermore, CGM use was consistently found to have increased detection in dysglycemia and glycemic variability compared to SMBG. In terms of clinical utility, CGM use led to more treatment adjustments and lower gestational weight gain (GWG). Lastly, CGM use showed higher postprandial glucose levels in GDM-complicated pregnancies than in normal pregnancies. Conclusion: Current updated evidence suggests that CGM is superior to SMBG among GDM pregnancies in terms of detecting hypoglycemic and hyperglycemic episodes, which might result in an improvement of maternal and fetal outcomes. In addition, CGM detects a wider glycemic variability in GDM mothers than non-GDM controls. Further research with larger sample sizes and complete pregnancy coverage is needed to explore the clinical utility such as screening and predictive values of CGM for GDM.

Diabetes Technology Use Among Pregnant and Nonpregnant Women with T1D in the T1D Exchange

BACKGROUND

Gestational tight glycemic control is critical for women with type 1 diabetes (T1D). Limited data exist on the adoption and retention of diabetes technologies among women in different parity strata.

METHODS

We compared T1D management between T1D Exchange clinic registry participants (mean age 28 ± 9 years, 84% white non-Hispanic, and median T1D duration 13 years) who were pregnant at enrollment or year 1 follow-up ("recently pregnant" between 2010 and 2013, n = 214), ever (but not recently) pregnant (n = 1540), and never pregnant (n = 2586). We examined self-reported maternal and fetal outcomes in 130 women who delivered a baby within the last year.

RESULTS

Recently pregnant women had the lowest hemoglobin A1c (6.5% pregnant vs. 7.8% ever pregnant vs. 8.0% never pregnant, P < 0.001). Recently pregnant women reported the highest use of continuous subcutaneous insulin infusion (74% vs. 60% vs. 58%, adjusted P < 0.001) and continuous glucose monitor (CGM) (36% vs.17% vs. 12%, adjusted P < 0.001) therapies compared with ever or never pregnant women, respectively, after adjusting for age, diabetes duration, and socioeconomic status. Among women 18-25 years old, CGM use was highest among recently pregnant women (adjusted P = 0.0022). Never pregnant women 26-45 years old had a higher use of CGM compared with younger counterparts (adjusted P < 0.001). Adverse maternal and fetal outcomes were common.

CONCLUSIONS

Despite high uptake levels of advanced diabetes technologies among pregnant women, rates of adverse maternal and fetal outcomes remain high. More studies are needed to determine how these technologies could be best used in pregnancy and postpartum to improve health outcomes among women with T1D.

Large-for-Gestational-Age Neonates in Type 1 Diabetes and Pregnancy: Contribution of Factors Beyond Hyperglycemia

Despite significant reductions in serious adverse perinatal outcomes for women with type 1 diabetes in pregnancy, the opposite effect has been observed for fetal overgrowth and associated complications, such as neonatal hypoglycemia, shoulder dystocia, and admission to the neonatal intensive care unit. In addition, infants born large for gestational age (LGA) have an increased lifetime risk of obesity, diabetes, and chronic disease. Although exposure to hyperglycemia plays an important role, women who seemingly achieve adequate glycemic control in pregnancy continue to experience a greater risk of excess fetal growth, leading to LGA neonates and macrosomia. We review potential contributors to excess fetal growth in pregnancies complicated by type 1 diabetes. In addition to hyperglycemia, we explore the role of glycemic variability, prepregnancy overweight and obesity, gestational weight gain, and maternal lipid levels. Greater understanding of the stimuli that drive excess fetal growth could lead to targeted management strategies in pregnant women with type 1 diabetes, potentially reducing the incidence of LGA neonates and the inherent risk of acute and long-term complications.

Fetal overgrowth in pregnancies complicated by diabetes: development of a clinical prediction index

PURPOSE

To develop an index to predict fetal overgrowth in pregnancies complicated by diabetes.

METHODS

Data were derived from a cohort of 275 women with singleton gestations in a collaborative diabetes in pregnancy program. Regression analysis incorporated clinical factors available in the first 20-30 weeks of pregnancy that were assigned beta-coefficient-based weights, the sum of which yielded a fetal overgrowth index (composite score).

RESULTS

Fifty-one (18.5%) pregnancies were complicated by fetal overgrowth. The derived index included five clinical factors: age ≤ 30, history of macrosomia, excessive gestational weight gain, enlarged fetal abdominal circumference, and fasting hyperglycemia. Area under the curve (AUC) for the index is 0.88 [95% confidence interval (CI) 0.82-0.92]. Cut-points were selected to identify "high-risk" and "low-risk" ranges (≥ 8 and ≤ 3) that have positive and negative predictive values of 84% (95% CI 70-98%) and 95% (95% CI 92-98%), respectively. The majority of women in our cohort (n = 182, 66%) had a "low-risk" index while 9% (n = 25) had a "high-risk" index. Sub-analyses of nulliparous women and women with gestational and pre-gestational diabetes revealed that the overgrowth index was equally or more predictive when applied separately to each of these groups.

CONCLUSION

This fetal overgrowth index that incorporates five clinical factors provides a means of predicting fetal overgrowth and thereby serves as a tool for targeting the allocation of healthcare resources and treatment individualization.

Glucose Profiles in Pregnant Women After a Gastric Bypass : Findings from Continuous Glucose Monitoring

BACKGROUND

The diagnosis of gestational diabetes mellitus (GDM) usually requires an oral glucose tolerance test, but this procedure seems inappropriate after gastric bypass surgery (Roux-en-Y gastric bypass (RYGB)) due to specific altered glycemic responses. We aimed here at describing continuous glucose monitoring (CGM) profile of pregnant women after RYGB.

METHODS

CGM was performed in 35 consecutive pregnant women after RYGB at 26.2 ± 5 weeks of gestation.

RESULTS

After RYGB, pregnant women display high postprandial interstitial glucose (IG) peaks and low IG before and 2 h after meals. The postprandial IG peak is reached early, within 54 ± 9 min. The maximum IG values reach 205 mg/dl, and the percentage of time above 140 mg/dl (6.6 ± 7 %) is similar to what is described in GDM women.

CONCLUSIONS

This study is the first to describe CGM profile in pregnant women after RYGB. CGM features are similar to those of non-pregnant post-RYGB patients, characterized by wide and rapid changes in postprandial IG, and high exposure to hyperglycemia. The exposure to hyperglycemia is similar to what is reported in GDM although the time to postprandial peak is shorter. CGM could be an additional useful approach to screen for glucose intolerance during pregnancy after RYGB.

Short- and long-term consequences for offspring exposed to maternal diabetes: a review

The prevalence of gestational diabetes mellitus is increasing, as is the worldwide prevalence of type 2 diabetes and obesity, even in children and adolescents. Exposure in utero to maternal diabetes carries several short-term consequences due mainly to maternal hyperglycemia, and consequent fetal hyperinsulinemia. Current evidence also supports the hypothesis that adult health and disease have developmental origins, and that disorders in early-life environments prompt metabolic imprinting that results in a greater risk of negative metabolic outcomes later in life. In particular, exposure in utero to maternal diabetes seems to influence long-term metabolic outcomes, carrying a higher risk of obesity and type 2 diabetes, and thus creating a vicious cycle for future generations. In this paper, the short- and long-term consequences of exposure in utero to hyperglycemia are reviewed, focusing particularly on the long-term metabolic consequences, and investigating the possible pathogenic mechanisms involved.

Masked hypoglycemia in pregnancy

BACKGROUND

Hypoglycemia is a major hindrance for optimal glycemic control in women with gestational diabetes mellitus (GDM) on insulin. In the present study, masked hypoglycemia (glucose <2.77mmol/L for ≥30 min) was estimated in pregnant women using a continuous glucose monitoring (CGM) system.

METHODS

Twenty pregnant women with GDM on insulin (cases) and 10 age-matched euglycemic pregnant women (controls) between 24 and 36 weeks gestation were recruited. Both groups performed self-monitoring of blood glucose (SMBG) and underwent CGM for 72 h to assess masked hypoglycemia. Masked hypoglycemic episodes were further stratified into two groups based on interstitial glucose (2.28-2.77 and ≤2.22 mmol/L).

RESULTS

Masked hypoglycemia was recorded in 35% (7/20) of cases and 40% (4/10) of controls using CGM, with an average of 1.28 and 1.25 episodes per subject, respectively. Time spent at glucose levels between 2.28 and 2.77 mmol/L did not differ between the two groups (mean 114 vs 90 min; P = 0.617), but cases spent a longer time with glucose ≤2.2 mmol/L. Babies born to women with GDM were significantly lighter than those born to controls (2860 vs 3290 g; P = 0.012). There was no significant difference in birth weight within the groups among babies born to women with or without hypoglycemia.

CONCLUSION

Euglycemic pregnant women and those with GDM on insulin had masked hypoglycemia. Masked hypoglycemia was not associated with adverse maternal or fetal outcomes. Therefore, low glucose levels in the hypoglycemic range may represent a physiologic adaptation in pregnancy. This response is exaggerated in women with GDM on insulin.

CGM, Pregnancy, and Remote Monitoring

The glycemic goals of pregnancy are very narrow to reduce excess risks for numerous maternal and fetal complications. Continuous glucose monitors (CGMs) may help women achieve glucose goals and reduce hypoglycemia. CGM use has been found to be safe and effective in pregnancies associated with diabetes. CGM use can accurately identify glycemic patterns among women with and without diabetes in pregnancy. The data on the effects of CGM use on maternal and fetal outcomes are conflicting. Using CGMs in conjunction with continuous subcutaneous insulin infusion therapy in pregnancies complicated by diabetes may improve outcomes. There are limitations of CGM use that affect patients in and outside of pregnancy, as well as specific barriers that only affect pregnant women. Of importance, CGM use does not replace standard clinical care, but may be used an adjunctive tool in pregnancy. CGM remote monitoring in pregnancy is an understudied field. In this study, we review the studies on CGM use in pregnancy.

Lower glycemic load meals reduce diurnal glycemic oscillations in women with risk factors for gestational diabetes

OBJECTIVE

Maternal glycemia plays a key role in fetal growth. We hypothesized that lower glycemic load (GL) meals (lower glycemic index, modestly lower carbohydrate) would substantially reduce day-long glucose variability in women at risk of gestational diabetes mellitus (GDM).

RESEARCH DESIGN AND METHODS

A crossover study of 17 women (mean±SD age 34.8±4 years; gestational weeks 29.3±1.3; body mass index 23.8±4.7 kg/m²) who consumed a low GL or a high GL diet in random order, 1-day each, over 2 consecutive days. Diets were energy-matched and fiber-matched with 5 meals per 24 hours. All food was provided. Continuous glucose monitoring was used to assess diurnal glycemia.

RESULTS

Maternal glucose levels were 51% lower on the low GL day with lower incremental area under the curve (iAUC±SEM 549±109 vs 1120±198 mmol/L min, p=0.015). Glycemic variability was significantly lower on the low GL day, as demonstrated by a lower average SD (0.7±0.1 vs 0.9±0.1, p<0.001) and lower mean amplitude of glycemic excursions (2.1±0.2 vs 2.7±0.2 mmol/L, p<0.001).

CONCLUSIONS

A lower GL meal plan in pregnancy acutely halves day-long maternal glucose levels and reduces glucose variability, providing further evidence to support the utility of a low GL diet in pregnancy.

Evaluation of Blood Glucose Meter Efficacy in an Antenatal Diabetes Clinic

BACKGROUND

The optimal treatment of diabetes in pregnancy requires accurate measurement of blood glucose levels, in order to minimize adverse outcomes for both mother and neonate. Self-monitoring of blood glucose is routinely used to measure glycemic control and to assess whether treatment targets are being met; however, the accuracy of blood glucose meters in pregnancy is unclear.

MATERIALS AND METHODS

Pregnant women with gestational, type 1, or type 2 diabetes mellitus were eligible to participate. Nonfasting capillary blood glucose levels were measured in duplicate using the BGStar(®) (Sanofi, Sydney, Australia) and FreeStyle Lite(®) (Abbott, Sydney) blood glucose meters. Venous blood samples were collected and analyzed for plasma glucose, hematocrit, and glycated hemoglobin. Capillary blood glucose was compared with plasma glucose and further assessed according to International Organization for Standardization (ISO) 15197:2013 standards.

RESULTS

One hundred ten women were recruited, providing 96 samples suitable for analysis. The mean ± SD laboratory plasma glucose level was 4.6 ± 1.4 mmol/L; the BGStar and FreeStyle Lite capillary blood glucose values were 5.3 ± 1.4 mmol/L and 5.0 ± 1.3 mmol/L, respectively. Both meters showed a positive bias (0.42 mmol/L for the FreeStyle Lite and 0.65 mmol/L for the BGStar). Furthermore, neither meter fulfilled the ISO 15197:2013 standards, and there was a nonsignificant improvement in meter performance at blood glucose levels of ≤4.2 mmol/L. Hematocrit did not affect the results of either blood glucose meter. Clarke Error Grid analysis demonstrated that approximately 70% of the results of both meters would lead to appropriate clinical action.

CONCLUSIONS

The BGStar and FreeStyle Lite blood glucose meters did not meet ISO 15197:2013 recommendations for blood glucose monitoring systems when assessed in a population of women with diabetes in pregnancy. Clinicians should consider this difference in blood glucose readings when making diabetes-related treatment decisions.

Diabetic pregnancy outcomes in mothers treated with basal insulin lispro protamine suspension or NPH insulin: a multicenter retrospective Italian study

OBJECTIVE

The aim of this study was to study the efficacy and safety of long-acting insulin analog insulin lispro protamine suspension (ILPS) in diabetic pregnant women.

METHODS

In a multicenter observational retrospective study, we evaluated pregnancy outcome in 119 women affected by type 1 diabetes and 814 with gestational diabetes (GDM) treated during pregnancy with ILPS, compared with a control group treated with neutral protamine hagedorn (NPH) insulin.

RESULTS

Among type 1 diabetic patients, fasting blood glucose at the end of pregnancy was significantly lower in ILPS-treated than in NPH-treated patients. HbA1c levels across pregnancy did not differ between groups. Caesarean section and preterm delivery rates were significantly lower in the ILPS-women. Fetal outcomes were similar in the ILPS and NPH groups. Among GDM women, fasting blood glucose at the end of pregnancy was significantly lower in ILPS-treated than in NPH-treated patients. Duration of gestation was significantly longer, caesarian section and preterm delivery rates were lower in the ILPS-treated group. In addition, there were significantly fewer babies with an excessive ponderal index or neonatal hypoglycemic episodes in the ILPS group than in the NPH group.

CONCLUSIONS

Association of ILPS with rapid-acting analogs in pregnancy is safe in terms of maternal and fetal outcomes.

Continuous glucose monitoring effects on maternal glycemic control and pregnancy outcomes in patients with gestational diabetes mellitus: a prospective cohort study

CONTEXT

Clinical evidence on the consequential effects of continuous glucose monitoring (CGM) on pregnancy outcomes in women with gestational diabetes mellitus (GDM) is scarcely available.

OBJECTIVE

Our objective was to evaluate the effectiveness of CGM on maternal glycemic control and pregnancy outcomes in patients with GDM .

PATIENTS

In total, 340 Chinese pregnant women with GDM were allocated to either the routine care group (n = 190) or the CGM group (n =150).

DESIGN AND SETTING

This was a prospective cohort study in the Department of Obstetrics of GuangDong Women and Children Hospital in China. Recruitment started in April 2011 and stopped in August 2012.

INTERVENTIONS

A 72-hour CGM system was used as a supplementary tool for glucose monitoring in the CGM group. PRIMARY OUTCOME MEASUREMENTS: The parameters of glycemic variability included mean blood glucose, the SD of blood glucose, mean amplitude of glycemic excursions (MAGEs), and the mean of daily differences. The maternal outcomes (preeclampsia and cesarean delivery) and composite neonatal outcomes were analyzed.

RESULTS

The SD of blood glucose, MAGEs, and mean of daily differences values were significantly lower in the CGM group compared with those of the routine care group (P < .001). Subjects in the CGM group were at lower risk of preeclampsia and primary cesarean delivery compared with the routine care group (P < .05). The mean infant birth weight of women in the CGM group was lower than infants of women in the routine care group (P < .001). The MAGE was associated with birth weight (β = 0.196, P < .001), and it was an independent factor for preeclampsia (odds ratio, 3.66; 95% confidence interval 2.16-6.20) and composite neonatal outcome (odds ratio, 1.34; 95% confidence interval 1.01-1.77).

CONCLUSIONS

The use of supplementary CGM combined with routine antenatal care can improve the glycemic control and pregnancy outcomes of patients with GDM.

Interstitium versus Blood Equilibrium in Glucose Concentration and its Impact on Subcutaneous Continuous Glucose Monitoring Systems

The relationship between both interstitial and blood glucose remains a debated topic, on which there is still no consensus. The experimental evidence suggests that blood and interstitial fluid glucose levels are correlated by a kinetic equilibrium, which as a consequence has a time and magnitude gradient in glucose concentration between blood and interstitium. Furthermore, this equilibrium can be perturbed by several physiological effects (such as foreign body response, wound-healing effect, etc.), with a consequent reduction of interstitial fluid glucose versus blood glucose correlation. In the present study, the impact of operating in the interstitium on continuous glucose monitoring systems (CGMs) will be discussed in depth, both for the application of CGMs in the management of diabetes and in other critical areas, such as tight glycaemic control in critically ill patients.

Poor pregnancy outcome in women with type 1 diabetes is predicted by elevated HbA1c and spikes of high glucose values in the third trimester

OBJECTIVE

To analyse data from a randomised, controlled study of prandial insulin aspart versus human insulin, both with NPH insulin, in pregnant women with type 1 diabetes for potential factors predicting poor pregnancy outcomes. RESEARCH DESIGN/METHOD: Post hoc analysis including 91 subjects randomised prior to pregnancy with known outcome in early pregnancy and 259 subjects randomised prior to pregnancy/during pregnancy of <10 weeks' gestation with known late-pregnancy outcomes. Poor early-pregnancy outcomes included fetal loss <22 gestational weeks and/or congenital malformation (n=18). Poor late-pregnancy outcomes included: composite endpoint including pre-eclampsia, preterm delivery and perinatal death (n=78); preterm delivery (n=63); and excessive fetal growth (n=88).

RESULTS

18 patients experienced a malformed/lost fetus in early pregnancy - none preceded by severe hypoglycaemia. Albuminuria in early pregnancy was a significant predictor of poor late-pregnancy outcome (composite endpoint; p=0.012). In the third trimester, elevated HbA1c, ≥ 1 plasma glucose (PG) measurement >11 mmol/L (198 mg/dL) and %PG values outside 3.9-7.0 mmol/L (70-126 mg/dL) were significant predictors of poor late-pregnancy outcomes (all p<0.05).

CONCLUSIONS

Elevated HbA1c, high glucose spikes and out-of-range %PG in the third trimester, and albuminuria in early pregnancy, are associated with poor late-pregnancy outcomes.

Glucose Fluctuations during Gestation: An Additional Tool for Monitoring Pregnancy Complicated by Diabetes

Continuous glucose monitoring (CGM) gives a unique insight into magnitude and duration of daily glucose fluctuations. Limited data are available on glucose variability (GV) in pregnancy. We aimed to assess GV in healthy pregnant women and cases of type 1 diabetes mellitus or gestational diabetes (GDM) and its possible association with HbA1c. CGM was performed in 50 pregnant women (20 type 1, 20 GDM, and 10 healthy controls) in all three trimesters of pregnancy. We calculated mean amplitude of glycemic excursions (MAGE), standard deviation (SD), interquartile range (IQR), and continuous overlapping net glycemic action (CONGA), as parameters of GV. The high blood glycemic index (HBGI) and low blood glycemic index (LBGI) were also measured as indicators of hyperhypoglycemic risk. Women with type 1 diabetes showed higher GV, with a 2-fold higher risk of hyperglycemic spikes during the day, than healthy pregnant women or GDM ones. GDM women had only slightly higher GV parameters than healthy controls. HbA1c did not correlate with GV indicators in type 1 diabetes or GDM pregnancies. We provided new evidence of the importance of certain GV indicators in pregnant women with GDM or type 1 diabetes and recommended the use of CGM specifically in these populations.

Glycemic variability in gestational diabetes mellitus and its association with β cell function

Maternal hyperglycemia in gestational diabetes mellitus (GDM), especially hyperglycemic excursions, is associated with increased risks of adverse pregnancy outcomes. Continuous glucose monitoring (CGM) system (CGMS) is better than intermittent self-measurements in detecting detailed glucose profiles on the magnitude and duration of glucose fluctuations. Hyperglycemia resulted from impaired β cell function. This study analyzed the characteristics of glycemic variability in GDM with 24-28 gestational weeks and its association with β cell function. Thirty GDM with 24-28 gestational weeks (GDM group) were included in this study, and 20 normal gestational women (NGW group) and 20 normal glucose regulation non-pregnant women (NGRW group) were set as controls. The three groups were monitored using the CGMS for consecutive 72 h. The parameters of glycemic variability included the standard deviation of blood glucose (SDBG), mean of continuous 24-h blood glucose (MBG), mean amplitude of glycemic excursions (MAGEs), and mean of daily differences (MODDs). Homeostasis model assessments were applied to access the insulin resistance (HOMA-IR). The early insulinogenic index (ΔI30/ΔG30) and the area under the curve of insulin (AUCI180) derived from 75-g oral glucose tolerance test were applied to evaluate the early-phase insulin secretion and second-phase insulin secretion, respectively. After CGM, MAGE and MBG value increased progressively from NGRW, NGW to GDM group (p < 0.05); MODD and SDBG values of GDM group were all higher than those of NGRW and NGW groups (p < 0.05), but there are no differences in MODD and SDBG between NGRW and NGW groups (p > 0.05). After comparison of β cell function, ΔI30/ΔG30 decreased progressively from NGRW, NGW to GDM group (p < 0.05); HOMA-IR and AUCI180 increased progressively from NGRW, NGW to GDM group (p < 0.05). MAGE value was correlated with ΔI30/ΔG30 and HOMA-IR in GDM group (r = -0.78 and 0.65, respectively, p < 0.05). Multiple linear stepwise regression analysis showed that ΔI30/ΔG30 and HOMA-IR were the independent factors of MAGE (β = -0.61, 0.34, respectively, p < 0.05). Glycemic variability in GDM was higher than in normal pregnant women, and glycemic variability evaluated by MAGE correlates well with impaired early-phase insulin secretion in GDM. Further large-scale studies are needed to formulate treatment strategies to make up for the impaired early-phase insulin secretion and flat glycemic variability, and analyze the association between pregnancy outcomes improvement and glycemic variability remission in GDM.

Role of continuous glucose monitoring in the management of diabetic pregnancy

Self-monitoring of blood glucose (SMBG) with intermittent capillary glucose fingerstick tests is currently the universally accepted method of glucose monitoring in pregnancy. During pregnancy SMBG tests are recommended before and after meals and before bed (typically 7 values/d). Continuous glucose monitoring systems consist of a disposable subcutaneous glucose-sensing device, electrochemically measuring glucose levels in subcutaneous tissues every 10 seconds, providing an average interstitial glucose value every 5 minutes (typically 288 values/d). From a research perspective this provides unprecedented insights into the pathophysiology of glucose metabolism, while from a clinical perspective it can facilitate enhanced patient-professional decision making, patient motivation, and improved glycaemic control. CGM has thus been described as a "roadmap for effective self-management" and as a "stepping stone in the journey towards a cure." This review will consider the lessons learned and evidence supporting current and potential future use of CGM in the management of diabetes in pregnancy.

Continuous glucose monitoring in type 1 diabetes

Continuous glucose monitors (CGM), devices that can measure interstitial glucose in "real time," have become widely available particularly for use in patients with diabetes, and their accuracy and ease of use have greatly improved over the last decade. A number of large and well-controlled clinical trials have firmly established their usefulness in improving metabolic control (as measured by HbA1C) and decreasing time spent in hypoglycemia in adults; however, data have been less robust proving benefit in children and adolescents. Benefits are clearly linked to near-continuous wear. Insulin dosing algorithms based on CGM glucose trends have proven useful in dissecting the large volume of data generated daily by these devices, although these are imperfect tools, particularly in children. The technology is likely to be most useful when integrated with insulin pump delivery systems (sensor augmented). In this review, we concentrate on the analysis of published results of the largest trials in adults and children, including the very young, with diabetes.

HbA(1c) and birthweight in women with pre-conception type 1 and type 2 diabetes: a population-based cohort study

AIMS/HYPOTHESIS

To investigate clinical and sociodemographic predictors of birthweight in singletons born to women with type 1 or type 2 diabetes.

METHODS

Normally formed singleton live births and intrapartum stillbirths, born to women with pre-conception diabetes during 1996-2008, were identified from the population-based Northern Diabetes in Pregnancy Survey (n = 1,505). Associations between potential predictors and birthweight were analysed by multiple regression.

RESULTS

Potentially modifiable independent predictors of increase in birthweight were pre-pregnancy care (adjusted regression coefficient [b] = 87.1 g; 95% CI 12.9, 161.3), increasing third-trimester HbA(1c) ≤7% (53 mmol/mol) (b = 310.5 g per 1% [11 mmol/mol]; 95% CI 246.3, 374.7) and increasing maternal BMI (b = 9.5 g per 1 kg/m(2); 95% CI 3.5, 15.5). Smoking during pregnancy (b = -145.1 g; 95% CI -231.4, -58.8), later gestation at first antenatal visit (b = -15.0 g; 95% CI -26.9, -3.0) and higher peri-conception HbA(1c) (b = -48.2 g; 95% CI -68.8, -27.6) were independently associated with birthweight reduction. Pre-pregnancy nephropathy (b = -282.7 g; 95% CI -461.8, -103.6) and retinopathy (b = -175.5 g; 95% CI -269.9, -81.0) were independent non-modifiable predictors of reduced birthweight, while greater maternal height was a non-modifiable predictor of increasing birthweight (b = 17.8 g; 95% CI 12.3, 23.2). Other predictors of birthweight increase were male sex, multiparity and increasing gestational age at delivery. Type or duration of diabetes, socioeconomic status and ethnicity were not associated with continuous birthweight.

CONCLUSIONS/INTERPRETATION

Poor glycaemic control before and throughout pregnancy is associated with abnormal fetal growth, with increasing peri-conception HbA(1c) predicting weight reduction and increasing third-trimester HbA(1c) predicting increased birthweight. Women with microvascular complications of diabetes may require increased surveillance to detect fetal growth restriction.