Analysis of Continuous Glucose Monitoring in Pregnant Women With Diabetes: Distinct Temporal Patterns of Glucose Associated With Large-for-Gestational-Age Infants

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.

Maternal night-eating pattern and glucose tolerance during pregnancy: study protocol for a longitudinal study

INTRODUCTION

Coordinating eating schedules with day-night cycles has been shown to improve glucose regulation in adults, but its association with gestational glycaemia is less clear. A better understanding on how eating time can influence glucose levels in pregnancy may improve strategies for gestational glycaemic control. This study aims to examine the association of maternal night-eating pattern with glucose tolerance in the second trimester of pregnancy, and to investigate how lifestyle factors may be related to night-eating pattern.

METHODS AND ANALYSIS

This is an observational longitudinal study that targets to recruit 200 pregnant women at 18-24 weeks' gestation from the KK Women's and Children's Hospital in Singapore. Data collection includes sociodemographics, lifestyle habits and obstetric information. Maternal dietary intake is collected using the 4-day food diary and food frequency questionnaire; while 24-hour physical activity, sedentary behaviour, sleep and light exposure are captured using the accelerometer at 18-24 weeks' gestation. Continuous glucose monitoring at 18-24 weeks' gestation, oral glucose tolerance test and insulin test at 24-28 weeks' gestation are performed to assess glycaemic outcomes. Multivariable generalised linear models will be used to analyse the association of maternal night-eating pattern (consumption of meal and snack during 1900-0659 hours) with glycaemic measures, and the associated factors of night-eating pattern, controlling for potential confounders. Recruitment began in March 2019 and is estimated to end in November 2020.

ETHICS AND DISSEMINATION

Ethical approval has been granted by the Centralised Institutional Review Board of SingHealth, Singapore (reference 2018/2529). The results will be presented at conferences and disseminated in journal articles.

TRIAL REGISTRATION NUMBER

NCT03803345.

High maternal early-pregnancy blood glucose levels are associated with altered fetal growth and increased risk of adverse birth outcomes

AIMS/HYPOTHESIS

The study aimed to assess the associations of maternal early-pregnancy blood glucose levels with fetal growth throughout pregnancy and the risks of adverse birth outcomes.

METHODS

In a population-based prospective cohort study among 6116 pregnant women, maternal non-fasting glucose levels were measured in blood plasma at a median 13.2 weeks of gestation (95% range 9.6-17.6). We measured fetal growth by ultrasound in each pregnancy period. We obtained information about birth outcomes from medical records and maternal sociodemographic and lifestyle factors from questionnaires.

RESULTS

Higher maternal early-pregnancy non-fasting glucose levels were associated with altered fetal growth patterns, characterised by decreased fetal growth rates in mid-pregnancy and increased fetal growth rates from late pregnancy onwards, resulting in an increased length and weight at birth (p ≤0.05 for all). A weaker association of maternal early-pregnancy non-fasting glucose levels with fetal head circumference growth rates was present. Higher maternal early-pregnancy non-fasting glucose levels were also associated with an increased risk of delivering a large-for-gestational-age infant, but decreased risk of delivering a small-for-gestational-age infant (OR 1.28 [95% CI 1.16, 1.41], OR 0.88 [95% CI 0.79, 0.98] per mmol/l increase in maternal early-pregnancy non-fasting glucose levels, respectively). These associations were not explained by maternal sociodemographic factors, lifestyle factors or BMI. Maternal early-pregnancy non-fasting glucose levels were not associated with preterm birth or delivery complications.

CONCLUSIONS/INTERPRETATION

Higher maternal early-pregnancy non-fasting glucose levels are associated with decreased fetal growth rates in mid-pregnancy and increased fetal growth rates from late pregnancy onwards, and an increased risk of delivering a large-for-gestational-age infant. Future preventive strategies need to focus on screening for an impaired maternal glucose metabolism from preconception and early pregnancy onwards to improve birth outcomes.

Pregnancy outcomes among women with type 1 diabetes mellitus using continuous subcutaneous insulin infusion versus multiple daily injections: A retrospective cohort study

Background

Insulin delivery options for pregnant women with type 1 diabetes mellitus are either continuous subcutaneous insulin infusion or multiple daily injections. The aim of this paper is to compare pregnancy outcomes in women with type 1 diabetes mellitus using continuous subcutaneous insulin infusion or multiple daily injections in pregnancy.

Methods

Retrospective single-centre cohort study of 298 pregnancies booked between 2006 and 2016. Descriptive analysis was performed for HbA1c values. Logistic regression models were created to compare selected maternal and neonatal outcomes.

Results

Continuous subcutaneous insulin infusion was associated with increased risk of large-for-gestational age (aOR 2.00, 95% CI 1.20-3.34) and preterm neonates (aOR 1.80, 95% CI 1.04-3.03). Continuous subcutaneous insulin infusion had no association with increased risk of adverse pregnancy outcomes. No difference in HbA1c values existed between groups.

Conclusion

Using continuous subcutaneous insulin infusion for type 1 diabetes mellitus through pregnancy is associated with increased risk of large-for-gestational age and preterm neonates, without increased risk of associated adverse maternal or neonatal outcomes.

Predictors of Large-for-Gestational-Age Birthweight Among Pregnant Women With Type 1 and Type 2 Diabetes: A Retrospective Cohort Study

OBJECTIVE

Our aim in this study was to compare the effects of risk factors for large-for-gestational-age (LGA) birthweight between women with type 1 and type 2 diabetes mellitus (TIDM and T2DM, respectively).

METHODS

A retrospective cohort study was conducted for women with T1DM (n=152) and T2DM (n=255) attending a diabetes/pregnancy clinic during the period from 2009 to 2016. Multiple logistic regression analysis was used to identify variables associated with LGA birthweight.

RESULTS

LGA was significantly higher in those with T1DM (39%) than T2DM (17%) (p<0.001). Among those with T1DM, there was a nonsignificant association between LGA and continuous subcutaneous insulin infusion (odds ratio, 1.17; 95% confidence interval, 0.99 to 1.39; p=0.06) and excess maternal weight gain (T1DM odds ratio, 1.19; 95% confidence interval, 0.99 to 1.43; p=0.069). In those with T2DM, there was an association between LGA and glycated hemoglobin at delivery (T2DM odds ratio, 1.10; 95% confidence interval, 1.02 to 1.19; p=0.01).

CONCLUSIONS

In the study population, glycemic control at delivery was predictive of LGA in women with T2DM, and there was a trend toward an association of maternal weight gain and continuous subcutaneous insulin infusion with LGA infants in T1DM. Further study is warranted to better guide targeted interventions to reduce high rates of LGA birthweight in T1DM/T2DM.

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 targets in type 1 diabetes pregnancy: every 5% time in range matters

With randomised trial data confirming that continuous glucose monitoring (CGM) is associated with improvements in maternal glucose control and neonatal health outcomes, CGM is increasingly used in antenatal care. Across pregnancy, the ambition is to increase the CGM time in range (TIR), while reducing time above range (TAR), time below range (TBR) and glycaemic variability measures. Pregnant women with type 1 diabetes currently spend, on average, 50% (12 h), 55% (13 h) and 60% (14 h) in the target range of 3.5-7.8 mmol/l (63-140 mg/dl) during the first, second and third trimesters, respectively. Hyperglycaemia, as measured by TAR, reduces from 40% (10 h) to 33% (8 h) during the first to third trimester. A TIR of >70% (16 h, 48 min) and a TAR of <25% (6 h) is achieved only in the final weeks of pregnancy. CGM TBR data are particularly sensor dependent, but regardless of the threshold used for individual patients, spending ≥4% of time (1 h) below 3.5 mmol/l or ≥1% of time (15 min) below 3.0 mmol/l is not recommended. While maternal hyperglycaemia is a well-established risk factor for obstetric and neonatal complications, CGM-based risk factors are emerging. A 5% lower TIR and 5% higher TAR during the second and third trimesters is associated with increased risk of large for gestational age infants, neonatal hypoglycaemia and neonatal intensive care unit admissions. For optimal neonatal outcomes, women and clinicians should aim for a TIR of >70% (16 h, 48 min) and a TAR of <25% (6 h), from as early as possible during pregnancy.

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.

Improving pregnancy outcomes in women with diabetes mellitus: modern management

Women with pre-existing (type 1 or type 2) diabetes mellitus are at increased risk of pregnancy complications, such as congenital malformations, preeclampsia and preterm delivery, compared with women who do not have diabetes mellitus. Approximately half of pregnancies in women with pre-existing diabetes mellitus are complicated by fetal overgrowth, which results in infants who are overweight at birth and at risk of birth trauma and, later in life, the metabolic syndrome, cardiovascular disease and type 2 diabetes mellitus. Strict glycaemic control with appropriate diet, use of insulin and, if necessary, antihypertensive treatment is the cornerstone of diabetes mellitus management to prevent pregnancy complications. New technology for managing diabetes mellitus is evolving and is changing the management of these conditions in pregnancy. For instance, in Europe, most women with pre-existing diabetes mellitus are treated with insulin analogues before and during pregnancy. Furthermore, many women are on insulin pumps during pregnancy, and the use of continuous glucose monitoring is becoming more frequent. In addition, smartphone application technology is a promising educational tool for pregnant women with diabetes mellitus and their caregivers. This Review covers how modern diabetes mellitus management with appropriate diet, insulin and antihypertensive treatment in patients with pre-existing diabetes mellitus can contribute to reducing the risk of pregnancy complications such as congenital malformations, fetal overgrowth, preeclampsia and preterm delivery.

Suboptimal Nocturnal Glucose Control Is Associated With Large for Gestational Age in Treated Gestational Diabetes Mellitus

OBJECTIVE

Continuous glucose monitoring (CGM) provides far greater detail about fetal exposure to maternal glucose across the 24-h day. Our aim was to examine the role of temporal glucose variation on the development of large for gestational age (LGA) infants in women with treated gestational diabetes mellitus (GDM).

RESEARCH DESIGN AND METHODS

We performed a prospective observational study of 162 pregnant women with GDM in specialist multidisciplinary antenatal diabetes clinics. Participants undertook 7-day masked CGM at 30-32 weeks' gestation. Standard summary indices and glycemic variability measures of CGM were calculated. Functional data analysis was applied to determine differences in temporal glucose profiles. LGA was defined as birth weight ≥90th percentile adjusted for infant sex, gestational age, maternal BMI, ethnicity, and parity.

RESULTS

Mean glucose was significantly higher in women who delivered an LGA infant (6.2 vs. 5.8 mmol/L, P = 0.025, or 111.6 mg/dL vs. 104.4 mg/dL). There were no significant differences in percentage time in, above, or below the target glucose range or in glucose variability measures (all P > 0.05). Functional data analysis revealed that the higher mean glucose was driven by a significantly higher glucose for 6 h overnight (0030-0630 h) in mothers of LGA infants (6.0 ± 1.0 mmol/L vs. 5.5 ± 0.8 mmol/L, P = 0.005, and 108.0 ± 18.0 mg/dL vs. 99.0 ± 14.4 mg/dL).

CONCLUSIONS

Mothers of LGA infants run significantly higher glucose overnight compared with mothers without LGA infants. Detecting and addressing nocturnal glucose control may help to further reduce rates of LGA in women with GDM.

Prediction of large-for-gestational-age infants in pregnancies complicated by obesity: A population-based cohort study

INTRODUCTION

Infants born large for gestational age (LGA) have increased risks of adverse perinatal outcomes. Maternal obesity, defined as body mass index (BMI) ≥30 kg/m² , is one of the most prevalent risk factors for LGA and the proportion of pregnancies complicated by obesity is increasing. Early identification of women with BMI ≥30 kg/m² at increased risk of giving birth to an LGA infant may open possibilities for prevention, aiming at decreasing the incidence of LGA.

MATERIAL AND METHODS

A population-based cohort study using information from the first-trimester screening database, which was cross-linked with the Swedish Medical Birth Register. The database included 139 277 full-term singletons without fetal anomalies born between 2006 and 2015 to mothers without prepregnancy diabetes. Of these, 9.1% (n = 12 704) were infants of mothers with BMI ≥30 kg/m² . For all women with BMI ≥30 kg/m² , a prediction model for LGA to be used in early pregnancy was constructed based on information on biochemical markers and maternal characteristics. A similar model, as well as a prepregnancy prediction model, were constructed for parous women with BMI ≥30 kg/m² . In parous women, data from the previous pregnancy were also used. Receiver operating characteristic curve and area under curve (AUC) were calculated.

RESULTS

The predictive models for LGA in parous women with BMI ≥30 kg/m² prepregnancy and in early pregnancy had AUCs of 0.80 (95% CI 0.78-0.82) and 0.81 (95% CI 0.79-0.82), respectively. For all women with BMI ≥30 kg/m² , the prediction of LGA in early pregnancy had an AUC of 0.66 (95% CI 0.64-0.67).

CONCLUSIONS

Performance of the prepregnancy and early pregnancy prediction models for LGA in parous women with BMI ≥30 kg/m² was good. The predictive capacity was largely driven by previous child's birthweight. First-trimester measurements of fetal size did not improve the predictive capacity in parous women. Predictions of LGA in all women with BMI ≥30 kg/m² in early pregnancy, without taking previous child's birthweight into account, remain difficult.

Women's Experiences of Day-and-Night Closed-Loop Insulin Delivery During Type 1 Diabetes Pregnancy

AIMS

Closed-loop insulin delivery has the potential to improve day-to-day glucose control in type 1 diabetes pregnancy. However, the psychosocial impact of day-and-night usage of automated closed-loop systems during pregnancy is unknown. Our aim was to explore women's experiences and relationships between technology experience and levels of trust in closed-loop therapy.

METHODS

We recruited 16 pregnant women with type 1 diabetes to a randomized crossover trial of sensor-augmented pump therapy compared to automated closed-loop therapy. We conducted semistructured qualitative interviews at baseline and follow-up. Findings from follow-up interviews are reported here.

RESULTS

Women described benefits and burdens of closed-loop systems during pregnancy. Feelings of improved glucose control, excitement and peace of mind were counterbalanced by concerns about technical glitches, CGM inaccuracy, and the burden of maintenance requirements. Women expressed varied but mostly high levels of trust in closed-loop therapy.

CONCLUSIONS

Women displayed complex psychosocial responses to day-and-night closed-loop therapy in pregnancy. Clinicians should consider closed-loop therapy not just in terms of its potential impact on biomedical outcomes but also in terms of its impact on users' lives.

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.

Intensive Glycemic Treatment During Type 1 Diabetes Pregnancy: A Story of (Mostly) Sweet Success!

Studies from Scotland and Canada confirm large increases in the incidence of pregnancies complicated by pregestational type 1 diabetes (T1D). With this increased antenatal workload comes more specialization and staff expertise, which may be important as diabetes technology use increases. While euglycemia remains elusive and obstetrical intervention (earlier delivery, increased operative deliveries) is increasing, there have been some notable successes in the past 5-10 years. These include a decline in the rates of congenital anomaly (Canada) and stillbirths (U.K.) and substantial reductions in both maternal hypoglycemia (both moderate and severe) across many countries. However, pregnant women with T1D still spend ∼30-45% of the time (8-11 h/day) hyperglycemic during the second and third trimesters. The duration of maternal hyperglycemia appears unchanged in routine clinical care over the past decade. This ongoing fetal exposure to maternal hyperglycemia likely explains the persistent rates of large for gestational age (LGA), neonatal hypoglycemia, and neonatal intensive care unit (NICU) admissions in T1D offspring. The Continuous Glucose Monitoring in Women With Type 1 Diabetes in Pregnancy Trial (CONCEPTT) found that pregnant women using real-time continuous glucose monitoring (CGM) spent 5% less time (1.2 h/day) hyperglycemic during the third trimester, with clinically relevant reductions in LGA, neonatal hypoglycemia, and NICU admissions. This article will review the progress in our understanding of the intensive glycemic treatment of T1D pregnancy, focusing in particular on the recent technological advances in CGM and automated insulin delivery. It suggests that even with advanced diabetes technology, optimal maternal dietary intake is needed to minimize the neonatal complications attributed to postprandial hyperglycemia.

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.

Biomarkers for Macrosomia Prediction in Pregnancies Affected by Diabetes

Large birthweight, or macrosomia, is one of the commonest complications for pregnancies affected by diabetes. As macrosomia is associated with an increased risk of a number of adverse outcomes for both the mother and offspring, accurate antenatal prediction of fetal macrosomia could be beneficial in guiding appropriate models of care and interventions that may avoid or reduce these associated risks. However, current prediction strategies which include physical examination and ultrasound assessment, are imprecise. Biomarkers are proving useful in various specialties and may offer a new avenue for improved prediction of macrosomia. Prime biomarker candidates in pregnancies with diabetes include maternal glycaemic markers (glucose, 1,5-anhydroglucitol, glycosylated hemoglobin) and hormones proposed implicated in placental nutrient transfer (adiponectin and insulin-like growth factor-1). There is some support for an association of these biomarkers with birthweight and/or macrosomia, although current evidence in this emerging field is still limited. Thus, although biomarkers hold promise, further investigation is needed to elucidate the potential clinical utility of biomarkers for macrosomia prediction for pregnancies affected by diabetes.

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

BACKGROUND

To examine trimester-specific associations among glycemic variability, fetal growth, and birthweight in pregnancies with type 1 diabetes mellitus (Type 1 DM).

METHODS

In this retrospective cohort study of 41 pregnant women with Type 1 DM, we used continuous glucose monitoring (CGM) data to calculate glycemic variability (coefficient of variation of glucose) over a 7-day interval in each trimester. Clinical data, including fetal biometry, birthweight, and perinatal complications, were extracted from medical records.

RESULTS

Women maintained good glycemic control during pregnancy, with mean HbA1c in the first, second, and third trimester 6.5%, 6.1%, and 6.4%, respectively. Sixty-three percent of infants were large for gestational age (LGA). Estimated fetal weight percentile (EFW%ile) and abdominal circumference percentile (AC%ile) increased during pregnancy, consistent with accelerated prenatal growth. Correlations between trimester-specific glycemic variability and EFW, AC, and birthweight were not statistically significant. After maternal age adjustment, glycemic variability was not associated with birthweight for any trimester (adj. β for first trimester: -38.46, 95% CI: -98.58 to 21.66; adj. β for second trimester: -12.20, 95% CI: -51.47 to 27.06; adj. β for third trimester: -26.26, 95% CI: -79.52 to 27.00).

CONCLUSIONS

The occurrence of LGA remains very high in contemporary U.S. women with Type 1 DM, despite the use of CGM and overall good glycemic control. Neither HbA1c nor glycemic variability predicted fetal overgrowth or birthweight. Since LGA is a key driver of maternal and newborn complications in pregnancies with Type 1 DM, our data emphasize the importance of investigating both glucose-dependent and glucose-independent underlying mechanisms.

Determinants of a good perinatal outcome in 588 pregnancies in women with type 1 diabetes

AIM

This study assessed pregnancy outcomes in women with type 1 diabetes (T1D) over the last 15 years and identified modifiable factors associated with good perinatal outcomes.

METHODS

Pregnancy outcomes were prospectively assessed in this cohort study of 588 singleton pregnancies (441 women) managed by standardized care from 2000 to 2014. A good perinatal outcome was defined as the uncomplicated delivery of a normally formed, non-macrosomic, full-term infant with no neonatal morbidity. Factors associated with good perinatal outcomes were identified by logistic regression.

RESULTS

The rate of severe congenital malformations was 1.5%, and 0.7% for perinatal mortality. The most frequent perinatal complications were macrosomia (41%), preterm delivery (16%) and neonatal hypoglycaemia (11%). Shoulder dystocia occurred in 2.6% of cases, but without sequelae. Perinatal outcomes were good in 254 (44%) pregnancies, and were associated with lower maternal HbA_1c values at delivery [adjusted odds ratio (aOR): 2.78, 95% CI: 2.04-3.70, for each 1% (11mmol/mol) absolute decrease], lower gestational weight gains (aOR: 1.06, 95% CI: 1.02-1.10) and absence of preeclampsia (aOR: 2.63, 95% CI: 1.09-6.25). The relationship between HbA_1c at delivery and a good perinatal outcome was continuous, with no discrimination threshold.

CONCLUSION

In our study, rates of severe congenital malformations and perinatal mortality were similar to those of the general population. Less severe complications, mainly macrosomia and late preterm delivery, persisted. Also, our study identified modifiable risk factors that could be targeted to further improve the prognosis of pregnancy in T1D.

Continuous glucose monitoring in pregnant women with Type 1 diabetes: benefits for mothers, using pumps or pens, and their babies

AIMS

To review the current literature on the use of continuous glucose monitoring during pregnancy in women with Type 1 diabetes.

METHODS

We searched the literature for randomized controlled trials using continuous glucose monitoring during pregnancy in women with Type 1 diabetes.

RESULTS

Three randomized trials were found and discussed in this review. One UK study found a reduction in large-for-gestational-age infants; however, only masked continuous glucose monitoring was used in that study. A Danish study used intermittent real-time continuous glucose monitoring and found no differences. The present authors conducted the CONCEPTT trial, in which pregnant women and women planning pregnancy were randomized to receive continuous glucose monitoring or standard care. We found a greater drop in HbA_1c , more time spent in the target range, and a reduction in some adverse neonatal outcomes in women using continuous glucose monitoring. Numbers-needed-to-treat to prevent a large-for-gestational-age infant, a neonatal intensive care unit admission for >24 h, and a neonatal hypoglycaemia event were low. These findings were seen in both injection and pump users and across all countries. Possible reasons for differences in study findings are discussed. In addition, several issues need further study. Glycaemic variability and differences in dietary intake may also have played a role. Despite excellent glycaemic control, babies continue to be large. More research is needed to understand the role of glucose targets and the dynamic placental processes involved in fetal growth.

CONCLUSIONS

The use of continuous glucose monitoring in women with Type 1 diabetes in pregnancy is associated with improved glycaemic control and neonatal outcomes. Further research examining the glycaemic and non-glycaemic variables involved in fetal growth and the cost-benefit of using continuous glucose monitoring in pregnancy is warranted.

Emerging Technologies for the Management of Type 1 Diabetes in Pregnancy

PURPOSE OF REVIEW

The purpose of the study is to discuss emerging technologies available in the management of type 1 diabetes in pregnancy.

RECENT FINDINGS

The latest evidence suggests that continuous glucose monitoring (CGM) should be offered to all women on intensive insulin therapy in early pregnancy. Studies have additionally demonstrated the ability of CGM to help gain insight into specific glucose profiles as they relate to glycaemic targets and pregnancy outcomes. Despite new studies comparing insulin pump therapy to multiple daily injections, its effectiveness in improving glucose and pregnancy outcomes remains unclear. Sensor-integrated insulin delivery (also called artificial pancreas or closed-loop insulin delivery) in pregnancy has been demonstrated to improve time in target and performs well despite the changing insulin demands of pregnancy. Emerging technologies show promise in the management of type 1 diabetes in pregnancy; however, research must continue to keep up as technology advances. Further research is needed to clarify the role technology can play in optimising glucose control before and during pregnancy as well as to understand which women are candidates for sensor-integrated insulin delivery.

Controversies and Advances in Gestational Diabetes-An Update in the Era of Continuous Glucose Monitoring

Diabetes in pregnancy, both preexisting type 1 or type 2 and gestational diabetes, is a highly prevalent condition, which has a great impact on maternal and fetal health, with short and long-term implications. Gestational Diabetes Mellitus (GDM) is a condition triggered by metabolic adaptation, which occurs during the second half of pregnancy. There is still a lot of controversy about GDM, from classification and diagnosis to treatment. Recently, there have been some advances in the field as well as recommendations from international societies, such as how to distinguish previous diabetes, even if first recognized during pregnancy, and newer diagnostic criteria, based on pregnancy outcomes, instead of maternal risk of future diabetes. These new recommendations will lead to a higher prevalence of GDM, and important issues are yet to be resolved, such as the cost-utility of this increase in diagnoses as well as the determinants for poor outcomes. The aim of this review is to discuss the advances in diagnosis and classification of GDM, as well as their implications in the field, the issue of hyperglycemia in early pregnancy and the role of hemoglobin A1c (HbA1c) during pregnancy. We have looked into the determinants of the poor outcomes predicted by the diagnosis by way of oral glucose tolerance tests, highlighting the relevance of continuous glucose monitoring tools, as well as other possible pathogenetic factors related to poor pregnancy outcomes.

Continuous Glucose Monitoring: A Review of Recent Studies Demonstrating Improved Glycemic Outcomes

Continuous Glucose Monitoring (CGM) has been demonstrated to be clinically valuable, reducing risks of hypoglycemia and hyperglycemia, glycemic variability (GV), and improving patient quality of life for a wide range of patient populations and clinical indications. Use of CGM can help reduce HbA1c and mean glucose. One CGM device, with accuracy (%MARD) of approximately 10%, has recently been approved for self-adjustment of insulin dosages (nonadjuvant use) and approved for reimbursement for therapeutic use in the United States. CGM had previously been used off-label for that purpose. CGM has been demonstrated to be clinically useful in both type 1 and type 2 diabetes for patients receiving a wide variety of treatment regimens. CGM is beneficial for people using either multiple daily injections (MDI) or continuous subcutaneous insulin infusion (CSII). CGM is used both in retrospective (professional, masked) and real-time (personal, unmasked) modes: both approaches can be beneficial. When CGM is used to suspend insulin infusion when hypoglycemia is detected until glucose returns to a safe level (low-glucose suspend), there are benefits beyond sensor-augmented pump (SAP), with greater reduction in the risk of hypoglycemia. Predictive low-glucose suspend provides greater benefits in this regard. Closed-loop control with insulin provides further improvement in quality of glycemic control. A hybrid closed-loop system has recently been approved by the U.S. FDA. Closed-loop control using both insulin and glucagon can reduce risk of hypoglycemia even more. CGM facilitates rigorous evaluation of new forms of therapy, characterizing pharmacodynamics, assessing frequency and severity of hypo- and hyperglycemia, and characterizing several aspects of GV.

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.

Translating HbA1c measurements into estimated average glucose values in pregnant women with diabetes

AIMS/HYPOTHESIS

This study aimed to examine the relationship between average glucose levels, assessed by continuous glucose monitoring (CGM), and HbA_1c levels in pregnant women with diabetes to determine whether calculations of standard estimated average glucose (eAG) levels from HbA_1c measurements are applicable to pregnant women with diabetes.

METHODS

CGM data from 117 pregnant women (89 women with type 1 diabetes; 28 women with type 2 diabetes) were analysed. Average glucose levels were calculated from 5-7 day CGM profiles (mean 1275 glucose values per profile) and paired with a corresponding (±1 week) HbA_1c measure. In total, 688 average glucose-HbA_1c pairs were obtained across pregnancy (mean six pairs per participant). Average glucose level was used as the dependent variable in a regression model. Covariates were gestational week, study centre and HbA_1c.

RESULTS

There was a strong association between HbA_1c and average glucose values in pregnancy (coefficient 0.67 [95% CI 0.57, 0.78]), i.e. a 1% (11 mmol/mol) difference in HbA_1c corresponded to a 0.67 mmol/l difference in average glucose. The random effects model that included gestational week as a curvilinear (quadratic) covariate fitted best, allowing calculation of a pregnancy-specific eAG (PeAG). This showed that an HbA_1c of 8.0% (64 mmol/mol) gave a PeAG of 7.4-7.7 mmol/l (depending on gestational week), compared with a standard eAG of 10.2 mmol/l. The PeAG associated with maintaining an HbA_1c level of 6.0% (42 mmol/mol) during pregnancy was between 6.4 and 6.7 mmol/l, depending on gestational week.

CONCLUSIONS/INTERPRETATION

The HbA_1c-average glucose relationship is altered by pregnancy. Routinely generated standard eAG values do not account for this difference between pregnant and non-pregnant individuals and, thus, should not be used during pregnancy. Instead, the PeAG values deduced in the current study are recommended for antenatal clinical care.

Large-for-gestational-age (LGA) neonate predicts a 2.5-fold increased odds of neonatal hypoglycaemia in women with type 1 diabetes

OBJECTIVE

The objective of the study is to assess the impact of maternal glycaemic control and large-for-gestational-age (LGA) infant size on the risk of developing neonatal hypoglycaemia in offspring of women with type 1 diabetes and to determine possible predictors of neonatal hypoglycaemia and LGA.

RESEARCH METHODS AND DESIGN

This retrospective cohort study evaluated pregnancies in 161 women with type 1 diabetes mellitus at a large urban centre between 2006 and 2010. Mean trimester A_1c values were categorized into five groups. Multiple logistic regression analyses were used to examine predictors of neonatal hypoglycaemia and large-for-gestational-age (LGA).

RESULTS

Hypoglycaemia occurred in 36.6% of neonates. There was not a linear association between trimester specific A_1c and LGA. After adjusting for maternal age, body mass index (BMI), smoking and premature delivery, neonatal hypoglycaemia was not linearly associated with A_1c in the first, second or third trimesters. LGA was the only significant predictor for neonatal hypoglycaemia (OR, 95% CI 2.51 [1.10, 5.70]) in logistic regression analysis that adjusted for glycaemic control, maternal age, smoking, prematurity and BMI. An elevated third trimester A_1c increased the odds of LGA (1.81 [1.03, 3.18]) after adjustment for smoking, parity and maternal BMI.

CONCLUSIONS

Large-for-gestational-age imparts a 2.5-fold increased odds of hypoglycaemia in neonates of women with type 1 diabetes and may be a better predictor of neonatal hypoglycaemia than maternal glycaemic control. Our data suggest that LGA neonates of women with type 1 diabetes should prompt increased surveillance for neonatal hypoglycaemia and that the presence of optimum maternal glycaemic control should not reduce this surveillance. Copyright © 2016 John Wiley & Sons, Ltd.

Seventy two-hour glucose monitoring profiles in mild gestational diabetes mellitus: differences from healthy pregnancies and influence of diet counseling

OBJECTIVE

To study glucose profiles of gestational diabetes (GDM) patients with 72 h of continuous glucose monitoring (CGM) either before (GDM1) or after (GDM2) dietary counseling, comparing them with nondiabetic (NDM) controls.

DESIGN AND METHODS

We performed CGM on 22 GDM patients; 11 before and 11 after dietary counseling and compared them to 11 healthy controls. Several physiological and clinical characteristics of the glucose profiles were compared across the groups, including comparisons for pooled 24-h measures and hourly median values, summary measures representing glucose exposure (area under the median curves) and variability (amplitude, standard deviation, interquartile range), and time points related to meals.

RESULTS

Most women (81.8%) in the GDM groups had fasting glucose <95mg/dL, suggesting mild GDM. Variability, glucose levels 1 and 2h after breakfast and dinner, peak values after dinner and glucose levels between breakfast and lunch, were all significantly higher in GDM1 than NDM (P<0.05 for all comparisons). The GDM2 results were similar to NDM in all aforementioned comparisons (P>0.05). Both GDM groups spent more time with glucose levels above 140mg/dL when compared with the NDM group. No differences among the groups were found for: pooled measurements and hourly comparisons, exposure, nocturnal, fasting, between lunch and dinner and before meals, as well as after lunch (P>0.05 for all).

CONCLUSION

The main differences between the mild GDM1 group and healthy controls were related to glucose variability and excursions above 140mg/dL, while glucose exposure was similar. Glucose levels after breakfast and dinner also discerned the GDM1 group. Dietary counseling was able to keep glucose levels to those of healthy patients.

Closed-Loop Insulin Delivery during Pregnancy in Women with Type 1 Diabetes

BACKGROUND

In patients with type 1 diabetes who are not pregnant, closed-loop (automated) insulin delivery can provide better glycemic control than sensor-augmented pump therapy, but data are lacking on the efficacy, safety, and feasibility of closed-loop therapy during pregnancy.

METHODS

We performed an open-label, randomized, crossover study comparing overnight closed-loop therapy with sensor-augmented pump therapy, followed by a continuation phase in which the closed-loop system was used day and night. Sixteen pregnant women with type 1 diabetes completed 4 weeks of closed-loop pump therapy (intervention) and sensor-augmented pump therapy (control) in random order. During the continuation phase, 14 of the participants used the closed-loop system day and night until delivery. The primary outcome was the percentage of time that overnight glucose levels were within the target range (63 to 140 mg per deciliter [3.5 to 7.8 mmol per liter]).

RESULTS

The percentage of time that overnight glucose levels were in the target range was higher during closed-loop therapy than during control therapy (74.7% vs. 59.5%; absolute difference, 15.2 percentage points; 95% confidence interval, 6.1 to 24.2; P=0.002). The overnight mean glucose level was lower during closed-loop therapy than during control therapy (119 vs. 133 mg per deciliter [6.6 vs. 7.4 mmol per liter], P=0.009). There were no significant differences between closed-loop and control therapy in the percentage of time in which glucose levels were below the target range (1.3% and 1.9%, respectively; P=0.28), in insulin doses, or in adverse-event rates. During the continuation phase (up to 14.6 additional weeks, including antenatal hospitalizations, labor, and delivery), glucose levels were in the target range 68.7% of the time; the mean glucose level was 126 mg per deciliter (7.0 mmol per liter). No episodes of severe hypoglycemia requiring third-party assistance occurred during either phase.

CONCLUSIONS

Overnight closed-loop therapy resulted in better glucose control than sensor-augmented pump therapy in pregnant women with type 1 diabetes. Women receiving day-and-night closed-loop therapy maintained glycemic control during a high proportion of the time in a period that encompassed antenatal hospital admission, labor, and delivery. (Funded by the National Institute for Health Research and others; Current Controlled Trials number, ISRCTN71510001.).

Management of Type 1 Diabetes in Pregnancy

Women with type 1 diabetes (T1DM) have unique needs during the preconception, pregnancy, and postpartum periods. Preconception counseling is essential for women with T1DM to minimize pregnancy risks. The goals of preconception care should be tight glycemic control with a hemoglobin A1c (A1C) < 7 % and as close to 6 % as possible, without significant hypoglycemia. This will lower risks of congenital malformations, preeclampsia, and perinatal mortality. The safety of medications should be assessed prior to conception. Optimal control of retinopathy, hypertension, and nephropathy should be achieved. During pregnancy, the goal A1C is near-normal at <6 %, without excessive hypoglycemia. There is no clear evidence that continuous subcutaneous insulin infusion (CSII) versus multiple daily injections (MDI) is superior in achieving the desired tight glycemic control of T1DM during pregnancy. Data regarding continuous glucose monitoring (CGM) in pregnant women with T1DM is conflicting regarding improved glycemic control. However, a recent CGM study does provide some distinct patterns of glucose levels associated with large for gestational age infants. Frequent eye exams during pregnancy are essential due to risk of progression of retinopathy during pregnancy. Chronic hypertension treatment goals are systolic blood pressure 110-129 mmHg and diastolic blood pressure 65-79 mmHg. Labor and delivery target plasma glucose levels are 80-110 mg/dl, and an insulin drip is recommended to achieve these targets during active labor. Postpartum, insulin doses must be reduced and glucoses closely monitored in women with T1DM because of the enhanced insulin sensitivity after delivery. Breastfeeding is recommended and should be highly encouraged due to maternal benefits including increased insulin sensitivity and weight loss and infant and childhood benefits including reduced prevalence of overweight. In this article, we discuss the care of pregnant patients with T1DM.

The role of sleep duration in diabetes and glucose control

Sleep curtailment is common in the Westernised world and coincides with an increase in the prevalence of type 2 diabetes mellitus (T2DM). This review considers the recently published evidence for whether sleep duration is involved in the development of T2DM in human subjects and whether sleep has a role to play in glucose control in people who have diabetes. Data from large, prospective studies indicate a U-shaped relationship between sleep duration and the development of T2DM. Smaller, cross-sectional studies also support a relationship between short sleep duration and the development of both insulin resistance and T2DM. Intervention studies show that sleep restriction leads to insulin resistance, with recent sleep extension studies offering tantalising data showing a potential benefit of sleep extension on glucose control and insulin sensitivity. In people with established diabetes the published literature shows an association between poor glucose control and both short and long sleep durations. However, there are currently no studies that determine the causal direction of this relationship, nor whether sleep interventions are likely to offer benefit for people with diabetes to help them achieve tighter glucose control.

Continuous Glucose Monitoring in Patients with Abnormal Glucose Tolerance during Pregnancy: A Case Series

Abnormal glucose tolerance during pregnancy is associated with perinatal complications. We used continuous glucose monitoring (CGM) in pregnant women with glucose intolerance to achieve better glycemic control and to evaluate the maternal glucose fluctuations. We also used CGM in women without glucose intolerance (the control cases). Furthermore, the standard deviation (SD) and mean amplitude of glycemic excursions (MAGE) were calculated for each case. For the control cases, the glucose levels were tightly controlled within a very narrow range; however, the SD and MAGE values in pregnant women with glucose intolerance were relativity high, suggesting postprandial hyperglycemia. Our results demonstrate that pregnant women with glucose intolerance exhibited greater glucose fluctuations compared with the control cases. The use of CGM may help to improve our understanding of glycemic patterns and may have beneficial effects on perinatal glycemic control, such as the detection of postprandial hyperglycemia in pregnant women.

Circadian clocks, obesity and cardiometabolic function

Life on earth is governed by the continuous 24-h cycle of light and dark. Organisms have adapted to this environment with clear diurnal rhythms in their physiology and metabolism, enabling them to anticipate predictable environmental fluctuations over the day and to optimize the timing of relevant biological processes to this cycle. These rhythms are regulated by molecular circadian clocks, and current evidence suggests that interactions between the central and peripheral molecular clocks are important in metabolic and vascular functions. Disrupting this process through mutations in the core clock genes or by interfering with the environmental zeitgebers that entrain the clock appear to modulate the function of cells and tissues, leading to an increased risk for cardiometabolic disease.