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.).

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 HbA1c levels in pregnant women with diabetes to determine whether calculations of standard estimated average glucose (eAG) levels from HbA1c 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) HbA1c measure. In total, 688 average glucose-HbA1c 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 HbA1c. RESULTS: There was a strong association between HbA1c and average glucose values in pregnancy (coefficient 0.67 [95% CI 0.57, 0.78]), i.e. a 1% (11 mmol/mol) difference in HbA1c 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 HbA1c 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 HbA1c 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 HbA1c-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.

Prepregnancy care and pregnancy outcomes in women with type 1 diabetes.

OBJECTIVE: The objective of this study was to examine the relationship between prepregnancy care, glycemic control, maternal hypoglycemia, and pregnancy outcomes in women with type 1 diabetes. RESEARCH DESIGN AND METHODS: This was a prospective observational cohort study of women with type 1 diabetes who delivered from 1991 to 2002. Outcome measures were attendance at a clinic for prepregnancy care, maternal HbA(1c) (A1C) throughout pregnancy, maternal severe hypoglycemic episodes, macrosomia, preeclampsia, premature delivery (delivery before 37 weeks), very premature delivery (delivery before 34 weeks), spontaneous abortion, and adverse pregnancy outcome (defined as major malformation, stillbirth, and neonatal death). RESULTS: There were 290 pregnancies, in which 110 (38%) women had prepregnancy care. The prepregnancy care group contained more primiparous women (54.7 vs. 40.6%; P = 0.021) and fewer smokers (9.4 vs. 28.7%; P < 0.0001). They registered earlier (6.6 vs. 8.3 weeks, P < 0.0001) and had a lower A1C at the initial visit (6.5% vs. 7.6%; P < 0.0001). Adverse pregnancy outcomes and very premature deliveries were significantly lower in women who received prepregnancy care (2.9 vs. 10.2%; P = 0.03 and 5.0 vs. 14.2%; P = 0.02, respectively). In contrast, between groups, there was no difference in A1C after 24 weeks or in the rates of macrosomia, preeclampsia, or maternal severe hypoglycemic episodes. CONCLUSIONS: Prepregnancy care was associated with improved glycemic control in early pregnancy and significant reductions in adverse pregnancy outcome (malformation, stillbirth, and neonatal death) and very premature delivery. However, prepregnancy care failed to have an impact on glycemic control in later pregnancy or to reduce the risk of macrosomia and preeclampsia.

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

OBJECTIVE: Continuous glucose monitoring (CGM) is increasingly used to assess glucose control in diabetes. The objective was to examine how analysis of glucose data might improve our understanding of the role temporal glucose variation has on large-for-gestational-age (LGA) infants born to women with diabetes. RESEARCH DESIGN AND METHODS: Functional data analysis (FDA) was applied to 1.68 million glucose measurements from 759 measurement episodes, obtained from two previously published randomized controlled trials of CGM in pregnant women with diabetes. A total of 117 women with type 1 diabetes (n = 89) and type 2 diabetes (n = 28) who used repeated CGM during pregnancy were recruited from secondary care multidisciplinary obstetric clinics for diabetes in the U.K. and Denmark. LGA was defined as birth weight ≥90th percentile adjusted for sex and gestational age. RESULTS: A total of 54 of 117 (46%) women developed LGA. LGA was associated with lower mean glucose (7.0 vs. 7.1 mmol/L; P < 0.01) in trimester 1, with higher mean glucose in trimester 2 (7.0 vs. 6.7 mmol/L; P < 0.001) and trimester 3 (6.5 vs. 6.4 mmol/L; P < 0.01). FDA showed that glucose was significantly lower midmorning (0900-1100 h) and early evening (1900-2130 h) in trimester 1, significantly higher early morning (0330-0630 h) and throughout the afternoon (1130-1700 h) in trimester 2, and significantly higher during the evening (2030-2330 h) in trimester 3 in women whose infants were LGA. CONCLUSIONS: FDA of CGM data identified specific times of day that maternal glucose excursions were associated with LGA. It highlights trimester-specific differences, allowing treatment to be targeted to gestational glucose patterns.

Preconception care for women with diabetes: is it effective and who should provide it?

The association between hyperglycaemia and congenital malformations was first recognised over 40 years ago and was followed by the development of preconception clinics for women with diabetes. A fresh look at preconception care is needed as many studies were conducted during the late 1970s and early 1980s, before the introduction of regular home blood glucose monitoring and glycosylated haemoglobin assays, and when many patients with diabetes had microvascular complications. Recent observational studies and a meta-analysis suggest preconception care is effective with an approximately threefold reduction in the risk of malformations. There is now a worldwide epidemic of type 2 diabetes, but only few studies of preconception care have included women with type 2 diabetes. Furthermore, few studies have addressed the relationship between preconception care and perinatal morbidity. This article will review the evidence for preconception care in women with diabetes, evaluate different models of preconception care and discuss future strategies.

Closed-loop insulin delivery during pregnancy complicated by type 1 diabetes.

OBJECTIVE: This study evaluated closed-loop insulin delivery with a model predictive control (MPC) algorithm during early (12-16 weeks) and late gestation (28-32 weeks) in pregnant women with type 1 diabetes. RESEARCH DESIGN AND METHODS: Ten women with type 1 diabetes (age 31 years, diabetes duration 19 years, BMI 24.1 kg/m(2), booking A1C 6.9%) were studied over 24 h during early (14.8 weeks) and late pregnancy (28.0 weeks). A nurse adjusted the basal insulin infusion rate from continuous glucose measurements (CGM), fed into the MPC algorithm every 15 min. Mean glucose and time spent in target (63-140 mg/dL), hyperglycemic (>140 to ≥ 180 mg/dL), and hypoglycemic (<63 to ≤ 50 mg/dL) were calculated using plasma and sensor glucose measurements. Linear mixed-effects models were used to compare glucose control during early and late gestation. RESULTS: During closed-loop insulin delivery, median (interquartile range) plasma glucose levels were 117 (100.8-154.8) mg/dL in early and 126 (109.8-140.4) mg/dL in late gestation (P = 0.72). The overnight mean (interquartile range) plasma glucose time in target was 84% (50-100%) in early and 100% (94-100%) in late pregnancy (P = 0.09). Overnight mean (interquartile range) time spent hyperglycemic (>140 mg/dL) was 7% (0-40%) in early and 0% (0-6%) in late pregnancy (P = 0.25) and hypoglycemic (<63 mg/dL) was 0% (0-3%) and 0% (0-0%), respectively (P = 0.18). Postprandial glucose control, glucose variability, insulin infusion rates, and CGM sensor accuracy were no different in early or late pregnancy. CONCLUSIONS: MPC algorithm performance was maintained throughout pregnancy, suggesting that overnight closed-loop insulin delivery could be used safely during pregnancy. More work is needed to achieve optimal postprandial glucose control.

Type 2 diabetes in pregnancy - An increasing problem.

The worldwide epidemic in type 2 diabetes has been associated with an increased diagnosis in young adults. This has lead to a rapid rise in the number of pregnancies complicated by type 2 diabetes. Studies have shown risk of serious adverse outcome, including congenital malformation and perinatal mortality, is the same, or increased, in type 2 diabetes compared to type 1 diabetes. Despite improved glycaemic control in type 2 diabetes compared to type 1 diabetes, rates of perinatal morbidity, including preterm birth and macrosomia, appear to be similar. Risk factors associated with poor pregnancy outcome in women with type 2 diabetes include obesity, ethnicity and poor pregnancy preparation. This review will cover practical aspects of management of type 2 diabetes before, during and after pregnancy, including prepregnancy care, safety of oral hypoglycaemic agents, glycaemic management during labour, and choice of effective contraception.

Effectiveness of a regional prepregnancy care program in women with type 1 and type 2 diabetes: benefits beyond glycemic control.

OBJECTIVE: To implement and evaluate a regional prepregnancy care program in women with type 1 and type 2 diabetes. RESEARCH DESIGN AND METHODS: Prepregnancy care was promoted among patients and health professionals and delivered across 10 regional maternity units. A prospective cohort study of 680 pregnancies in women with type 1 and type 2 diabetes was performed. Primary outcomes were adverse pregnancy outcome (congenital malformation, stillbirth, or neonatal death), congenital malformation, and indicators of pregnancy preparation (5 mg folic acid, gestational age, and A1C). Comparisons were made with a historical cohort (n = 613 pregnancies) from the same units during 1999-2004. RESULTS: A total of 181 (27%) women attended, and 499 women (73%) did not attend prepregnancy care. Women with prepregnancy care presented earlier (6.7 vs. 7.7 weeks; P < 0.001), were more likely to take 5 mg preconception folic acid (88.2 vs. 26.7%; P < 0.0001) and had lower A1C levels (A1C 6.9 vs. 7.6%; P < 0.0001). They had fewer adverse pregnancy outcomes (1.3 vs. 7.8%; P = 0.009). Multivariate logistic regression confirmed that in addition to glycemic control, lack of prepregnancy care was independently associated with adverse outcome (odds ratio 0.2 [95% CI 0.05-0.89]; P = 0.03). Compared with 1999-2004, folic acid supplementation increased (40.7 vs. 32.5%; P = 0.006) and congenital malformations decreased (4.3 vs. 7.3%; P = 0.04). CONCLUSIONS: Regional prepregnancy care was associated with improved pregnancy preparation and reduced risk of adverse pregnancy outcome in type 1 and type 2 diabetes. Prepregnancy care had benefits beyond improved glycemic control and was a stronger predictor of pregnancy outcome than maternal obesity, ethnicity, or social disadvantage.

Effectiveness of continuous glucose monitoring in pregnant women with diabetes: randomised clinical trial.

OBJECTIVE: To evaluate the effectiveness of continuous glucose monitoring during pregnancy on maternal glycaemic control, infant birth weight, and risk of macrosomia in women with type 1 and type 2 diabetes. DESIGN: Prospective, open label randomised controlled trial. SETTING: Two secondary care multidisciplinary obstetric clinics for diabetes in the United Kingdom. PARTICIPANTS: 71 women with type 1 diabetes (n=46) or type 2 diabetes (n=25) allocated to antenatal care plus continuous glucose monitoring (n=38) or to standard antenatal care (n=33). INTERVENTION: Continuous glucose monitoring was used as an educational tool to inform shared decision making and future therapeutic changes at intervals of 4-6 weeks during pregnancy. All other aspects of antenatal care were equal between the groups. MAIN OUTCOME MEASURES: The primary outcome was maternal glycaemic control during the second and third trimesters from measurements of HbA(1c) levels every four weeks. Secondary outcomes were birth weight and risk of macrosomia using birthweight standard deviation scores and customised birthweight centiles. Statistical analyses were done on an intention to treat basis. RESULTS: Women randomised to continuous glucose monitoring had lower mean HbA(1c) levels from 32 to 36 weeks' gestation compared with women randomised to standard antenatal care: 5.8% (SD 0.6) v 6.4% (SD 0.7). Compared with infants of mothers in the control arm those of mothers in the intervention arm had decreased mean birthweight standard deviation scores (0.9 v 1.6; effect size 0.7 SD, 95% confidence interval 0.0 to 1.3), decreased median customised birthweight centiles (69% v 93%), and a reduced risk of macrosomia (odds ratio 0.36, 95% confidence interval 0.13 to 0.98). CONCLUSION: Continuous glucose monitoring during pregnancy is associated with improved glycaemic control in the third trimester, lower birth weight, and reduced risk of macrosomia. TRIAL REGISTRATION: Current Controlled Trials ISRCTN84461581.

Changes in the glycemic profiles of women with type 1 and type 2 diabetes during pregnancy.

OBJECTIVE: To examine the changes in glycemic excursions that occur during pregnancy using continuous glucose monitoring and to compare patterns of glycemia in pregnant women with type 1 and type 2 diabetes. RESEARCH DESIGN AND METHODS: An observational data analysis was performed from a prospective randomized study of continuous glucose monitoring in 57 women with pregestational type 1 (n = 40) or type 2 (n = 17) diabetes with 7-day continuous glucose monitoring system profiles during each trimester. Serial glucose measurements were divided into periods of euglycemia (70-140 mg/dl), hyperglycemia (>140 mg/dl), and hypoglycemia (<70 mg/dl). Generalized linear mixed effects models were fitted to the repeated measures data to determine how these glycemic characteristics varied during gestation and by diabetes type. RESULTS: A total of 180 continuous glucose profiles were examined (140 type 1 diabetes, 40 type 2 diabetes), providing 20,433 h of data for analysis (16,117 h type 1 diabetes, 4,316 type 2 diabetes). Women with type 2 diabetes spend approximately 33% less time hyperglycemic throughout pregnancy than women with type 1 diabetes (P = 0.005), with a significantly more rapid reduction in time spent hyperglycemic in early pregnancy (P = 0.02). Although women with type 2 diabetes spend less overall time hypoglycemic (P = 0.04), their risk of nocturnal hypoglycemia is equivalent to that of women with type 1 diabetes (blood glucose level <70 mg/dl, P = 0.9; blood glucose level <50 mg/dl, P = 0.2). CONCLUSIONS: Continuous glucose monitoring reveals clear differences in the level of glycemic control that exist in women with type 1 and type 2 diabetes. These data will guide therapeutic interventions aimed at optimizing glycemic control and improving the pregnancy outcomes of both type 1 and type 2 diabetes.