The influence of carbohydrate consumption on glycemic control in pregnant women with type 1 diabetes

Danish Diabetes Birth Registry 2: a study protocol of a national prospective cohort study to monitor outcomes of pregnancies of women with pre-existing diabetes

INTRODUCTION

Despite technological developments and intensified care, pregnancies in women with pre-existing diabetes are still considered high-risk pregnancies. The rate of adverse outcomes in pregnancies affected by diabetes in Denmark is currently unknown, and there is a limited understanding of mechanisms contributing to this elevated risk. To address these gaps, the Danish Diabetes Birth Registry 2 (DDBR2) was established. The aims of this registry are to evaluate maternal and fetal-neonatal outcomes based on 5 years cohort data, and to identify pathophysiology and risk factors associated with short-term and long-term outcomes of pregnancies in women with pre-existing diabetes.

METHODS AND ANALYSIS

The DDBR2 registry is a nationwide 5-year prospective cohort with an inclusion period from February 2023 to February 2028 of pregnancies in women with all types of pre-existing diabetes and includes registry, clinical and questionnaire data and biological samples of mother-partner-child trios. Eligible families (parents age ≥18 years and sufficient proficiency in Danish or English) can participate by either (1) basic level data obtained from medical records (mother and child) and questionnaires (partner) or (2) basic level data and additional data which includes questionnaires (mother and partner) and blood samples (all). The primary maternal outcome is Hemoglobin A1c (HbA1c) levels at the end of pregnancy and the primary offspring endpoint is the birth weight SD score. The DDBR2 registry will be complemented by genetic, epigenetic and metabolomic data as well as a biobank for future research, and the cohort will be followed through data from national databases to illuminate possible mechanisms that link maternal diabetes and other parental factors to a possible increased risk of adverse long-term child outcomes.

ETHICS AND DISSEMINATION

Approval from the Ethical Committee is obtained (S-20220039). Findings will be sought published in international scientific journals and shared among the participating hospitals and policymakers.

TRIAL REGISTRATION NUMBER

NCT05678543.

Management of type 1 diabetes in pregnancy: update on lifestyle, pharmacological treatment, and novel technologies for achieving glycaemic targets

Glucose concentrations within target, appropriate gestational weight gain, adequate lifestyle, and, if necessary, antihypertensive treatment and low-dose aspirin reduces the risk of pre-eclampsia, preterm delivery, and other adverse pregnancy and neonatal outcomes in pregnancies complicated by type 1 diabetes. Despite the increasing use of diabetes technology (ie, continuous glucose monitoring and insulin pumps), the target of more than 70% time in range in pregnancy (TIRp 3·5-7·8 mmol/L) is often reached only in the final weeks of pregnancy, which is too late for beneficial effects on pregnancy outcomes. Hybrid closed-loop (HCL) insulin delivery systems are emerging as promising treatment options in pregnancy. In this Review, we discuss the latest evidence on pre-pregnancy care, management of diabetes-related complications, lifestyle recommendations, gestational weight gain, antihypertensive treatment, aspirin prophylaxis, and the use of novel technologies for achieving and maintaining glycaemic targets during pregnancy in women with type 1 diabetes. In addition, the importance of effective clinical and psychosocial support for pregnant women with type 1 diabetes is also highlighted. We also discuss the contemporary studies examining HCL systems in type 1 diabetes during pregnancies.

Secular trend for increasing birthweight in offspring of pregnant women with type 1 diabetes: is improved placentation the reason?

Despite enormous progress in managing blood glucose levels, pregnancy in women with type 1 diabetes still carries risks for the growing fetus. While, previously, fetal undergrowth was not uncommon in these women, with improved maternal glycaemic control we now see an increased prevalence of fetal overgrowth. Besides short-term implications, offspring of women with type 1 diabetes are more likely to become obese and to develop diabetes and features of the metabolic syndrome. Here, we argue that the increase in birthweight is paradoxically related to improved glycaemic control in the pre- and periconceptional periods. Good glycaemic control reduces the prevalence of microangiopathy and improves placentation in early pregnancy, which may lead to unimpeded fetal nutrition. Even mild maternal hyperglycaemia may then later result in fetal overnutrition. This notion is supported by circumstantial evidence that lower HbA_1c levels as well as increases in markers of placental size and function in early pregnancy are associated with large-for-gestational age neonates. We also emphasise that neonates with normal birthweight can have excessive fat deposition. This may occur when poor placentation leads to initial fetal undergrowth, followed by fetal overnutrition due to maternal hyperglycaemia. Thus, the complex interaction of glucose levels during different periods of pregnancy ultimately determines the risk of adiposity, which can occur in fetuses with both normal and elevated birthweight. Prevention of fetal adiposity calls for revised goal setting to enable pregnant women to maintain blood glucose levels that are closer to normal. This could be supported by continuous glucose monitoring throughout pregnancy and appropriate maternal gestational weight gain. Future research should consider the measurement of adiposity in neonates.

Carbohydrate quantity is more closely associated with glycaemic control than weight in pregnant women with type 1 diabetes: Insights from the Diabetes and Pre-eclampsia Intervention Trial (DAPIT)

BACKGROUND

The present study aimed to explore the relationships between carbohydrate intake, body mass index (BMI) and glycaemic control (HbA1c) in pregnant women with type 1 diabetes mellitus (T1DM) METHODS: Secondary analysis of data was undertaken to assess dietary intake in a cohort of women who participated in a randomised controlled trial (RCT) of antioxidant supplementation to prevent preeclampsia (DAPIT¹⁰ ). Study-specific peripheral venous blood samples were obtained for HbA1c at 26 and 34 weeks. Diet was collected using a validated semiquantitative food frequency questionnaire at 26-28 weeks of gestation which assessed dietary intake over 2 weeks. Mean daily average nutrient intakes were analysed using Q Builder nutritional software and SPSS, version 25.

RESULTS

Dietary data were available for 547 pregnant women (72% of cohort) aged 29 years (95% confidence interval [CI] = 28.9-29.9) with average diabetes duration 11.8 years (95% confidence interval = 11.1-12.6). Average body mass index (BMI) (<16 weeks of gestation) was 26.7 kg/m² (95% CI = 26.3 -27, range 18.8-45.6 kg/m² ); 43% (n = 234) were overweight (BMI = 25.0-29.9 kg/m² ) and 20% (n = 112) were obese (BMI ≥ 30 kg/m² ). Differences in HbA1c and carbohydrate quantity and quality were found when adjusted for age and insulin dose. No differences between BMI group were observed for total carbohydrate and glycaemic control; however, differences were noted in fibre and glycaemic index.

CONCLUSIONS

Average quantity of dietary carbohydrate influenced HbA1c when adjusted for insulin dose however, BMI had less impact. More research is required on the relationship between carbohydrate consumption and glycaemic control in pregnancy.

Dietary Advice to Support Glycaemic Control and Weight Management in Women with Type 1 Diabetes during Pregnancy and Breastfeeding

In women with type 1 diabetes, the risk of adverse pregnancy outcomes, including congenital anomalies, preeclampsia, preterm delivery, foetal overgrowth and perinatal death is 2-4-fold increased compared to the background population. This review provides the present evidence supporting recommendations for the diet during pregnancy and breastfeeding in women with type 1 diabetes. The amount of carbohydrate consumed in a meal is the main dietary factor affecting the postprandial glucose response. Excessive gestational weight gain is emerging as another important risk factor for foetal overgrowth. Dietary advice to promote optimized glycaemic control and appropriate gestational weight gain is therefore important for normal foetal growth and pregnancy outcome. Dietary management should include advice to secure sufficient intake of micro- and macronutrients with a focus on limiting postprandial glucose excursions, preventing hypoglycaemia and promoting appropriate gestational weight gain and weight loss after delivery. Irrespective of pre-pregnancy BMI, a total daily intake of a minimum of 175 g of carbohydrate, mainly from low-glycaemic-index sources such as bread, whole grain, fruits, rice, potatoes, dairy products and pasta, is recommended during pregnancy. These food items are often available at a lower cost than ultra-processed foods, so this dietary advice is likely to be feasible also in women with low socioeconomic status. Individual counselling aiming at consistent timing of three main meals and 2-4 snacks daily, with focus on carbohydrate amount with pragmatic carbohydrate counting, is probably of value to prevent both hypoglycaemia and hyperglycaemia. The recommended gestational weight gain is dependent on maternal pre-pregnancy BMI and is lower when BMI is above 25 kg/m². Daily folic acid supplementation should be initiated before conception and taken during the first 12 gestational weeks to minimize the risk of foetal malformations. Women with type 1 diabetes are encouraged to breastfeed. A total daily intake of a minimum of 210 g of carbohydrate is recommended in the breastfeeding period for all women irrespective of pre-pregnancy BMI to maintain acceptable glycaemic control while avoiding ketoacidosis and hypoglycaemia. During breastfeeding insulin requirements are reported approximately 20% lower than before pregnancy. Women should be encouraged to avoid weight retention after pregnancy in order to reduce the risk of overweight and obesity later in life. In conclusion, pregnant women with type 1 diabetes are recommended to follow the general dietary recommendations for pregnant and breastfeeding women with special emphasis on using carbohydrate counting to secure sufficient intake of carbohydrates and to avoid excessive gestational weight gain and weight retention after pregnancy.

Impact of Carbohydrate Counting Method during Pregnancy in Women with Pregestational Diabetes Mellitus: A Controlled Clinical Trial

OBJECTIVE

 To evaluate the effect of the carbohydrate counting method (CCM) on glycemic control, maternal, and perinatal outcomes of pregnant women with pregestational diabetes mellitus (DM).

METHODS

 Nonrandomized controlled clinical trial performed with 89 pregnant women who had pregestational DM and received prenatal care in a public hospital in Rio de Janeiro, state of Rio de Janeiro, Brazil, between 2009 and 2014, subdivided into historic control group and intervention group, not simultaneous. The intervention group (n = 51) received nutritional guidance from the carbohydrate counting method (CCM), and the historical control group (n = 38), was guided by the traditional method (TM). The Mann-Whitney test or the Wilcoxon test were used to compare intra- and intergroup outcomes and analysis of variance (ANOVA) for repeated measures, corrected by the Bonferroni post-hoc test, was used to assess postprandial blood glucose.

RESULTS

 Only the CCM group showed a reduction in fasting blood glucose. Postprandial blood glucose decreased in the 2^nd (p = 0.00) and 3^rd (p = 0.00) gestational trimester in the CCM group, while in the TM group the reduction occurred only in the 2^nd trimester (p = 0.015). For perinatal outcomes and hypertensive disorders of pregnancy, there were no differences between groups. Cesarean delivery was performed in 82% of the pregnant women and was associated with hypertensive disorders (gestational hypertension or pre-eclampsia; p = 0.047).

CONCLUSION

 Both methods of nutritional guidance contributed to the reduction of postprandial glycemia of women and no differences were observed for maternal and perinatal outcomes. However, CCM had a better effect on postprandial glycemia and only this method contributed to reducing fasting blood glucose throughout the intervention.

REBEC CLINICAL TRIALS DATABASE

 The present study was registered in the ReBEC Clinical Trials Database (Registro Brasileiro de Ensaios Clínicos, number RBR-524z9n).

Nutrition in pregnancy with diabetes mellitus

The nutritional needs of diabetic pregnancies are different from normal pregnancies. Differences in nutritional recommendations can also be seen between pregnant women who are using and who are not using insulin therapy. In this literature review, recommendations for different meal proportions of carbohydrates, proteins, and fats in the diets of pregnant women with diabetes mellitus are listed. Different meal plans were also addressed in this group of patients. The role of exercise in the management of diabetes in pregnancy is undeniable and different approaches found in the literature are presented.

Dietary intake of carbohydrates in pregnant women with type 1 diabetes-A narrative review

In pregnant women with type 1 diabetes, a low but sufficient, intake of carbohydrates is important to aim for near normal glycemic control. However, knowledge about the carbohydrate intake in this group is limited. To assess the average quantity and quality of carbohydrate intake in pregnant women with type 1diabetes compared to healthy pregnant women and current dietary reference intakes. A narrative literature search was performed in PubMed, Embase, and Cochrane Library and by using a snow-ball search technique to identify papers published on studies conducted in industrialized countries within the last 20 years. Intakes of carbohydrate were assessed qualitatively in relation to the Dietary Reference Intakes recommended by the American Diabetes Association and quantitatively as mean intake of dietary fiber. Five observational studies including 810 pregnant women with type 1 diabetes and 15 observational studies with a total of 118,246 healthy pregnant women were identified. The mean total carbohydrate intake was within the Acceptable Macronutrient Distribution Range (45%-64% of energy intake) in both groups. In pregnant women with type 1 diabetes, the average total intake was 218 ± 19 g/day, which was 20% (53 g/day) lower than in healthy pregnant women. Mean intake of dietary fiber in women with diabetes was lower than the recommended adequate intake for healthy women. With the limitations of pronounced heterogeneity across the included studies, pregnant women with type 1 diabetes reported a mean total carbohydrate intake, which was lower than in healthy pregnant women but still within the recommended range.

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

AIM

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Management of pregestational diabetes mellitus: a comparison of guidelines

Background: Pregestational diabetes is associated with adverse maternal and neonatal outcomes. The aim of this study was to summarize and compare evidence-based recommendations on pregestational diabetes and to focus especially on issues related to the management of this entity.Materials and methods: A descriptive review of three recently published national guidelines on pregestational diabetes was conducted: the American Diabetes Association on "Diabetes in Pregnancy: Standards of Medical Care in Diabetes - 2019," the National Institute for Health and Care Excellence on "Diabetes in pregnancy: management from preconception to the postnatal period" and the American College of Obstetricians and Gynecologists on "Pregestational Diabetes Mellitus." These guidelines were compared according to recommendations on management, during the preconception, antenatal, intrapartum and postpartum period.Results: There were many similar recommendations regarding the preconception counseling, the antepartum assessment by specialists, the glycemic control target levels, the pharmacologic treatment and the postpartum period among the three guidelines. On the other hand, the American Diabetes Association makes no recommendations regarding fetal monitoring and obstetric management during pregnancy and the intrapartum period, while there are several similarities between the other two guidelines.Conclusions: The adoption of an international consensus based on evidence - based guidelines will increase the awareness of the healthcare professionals on the management of pregestational diabetes, leading that way to more favorable perinatal outcomes.

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.

Lower daily carbohydrate consumption than recommended by the Institute of Medicine is common among women with type 2 diabetes in early pregnancy in Denmark

AIMS

To secure adequate carbohydrate supply in pregnancy, the Institute of Medicine (IOM) recommends a minimum amount of carbohydrates of 175 g daily. Currently a low carbohydrate diet is a popular health trend in the general population and this might also be common among overweight and obese pregnant women with type 2 diabetes (T2D). Thus, we explored carbohydrate consumption among pregnant women with T2D including women with type 1 diabetes (T1D) for comparison.

METHODS

A retrospective cohort study of consecutive women with T2D (N = 96) and T1D (N = 108), where dietary records were collected at the first antenatal visit.

RESULTS

Among women with T2D and T1D, bodyweight at the first visit was 90.8 ± 22 (mean ± SD) and 75.5 ± 15 kg (P < 0.001) while HbA1c was 6.6 ± 1.2% (49 ± 13 mmol/mol) and 6.6 ± 0.8% (48 ± 8 mmol/mol), P = 0.8, respectively. The average daily carbohydrate consumption from the major carbohydrate sources was similar in the two groups (159 ± 56 and 167 ± 48 g, P = 0.3), as was the level of total daily physical activity (median (interquartile range)): 215 (174-289) and 210 (178-267) metabolic equivalent of task-hour/week (P = 0.9). A high proportion of women with T2D and T1D (52% and 40%, P = 0.08) consumed fewer carbohydrates than recommended by the IOM. The prevalence of ketonuria (≥4 mmol/L) was 1% in both groups.

CONCLUSIONS

In early pregnancy, a lower daily carbohydrate consumption than recommended by the IOM was common among women with T2D. The results were quite similar to women with T1D, despite a markedly higher bodyweight in women with T2D. Reassuringly, ketonuria was rare in both groups.

Breastfeeding at night is rarely followed by hypoglycaemia in women with type 1 diabetes using carbohydrate counting and flexible insulin therapy

AIMS/HYPOTHESIS

Hypoglycaemia in association with breastfeeding is a feared condition in mothers with type 1 diabetes. Thus, routine carbohydrate intake at each breastfeed, particularly at night, is often recommended despite lack of evidence. We aimed to evaluate glucose levels during breastfeeding, focusing on whether night-time breastfeeding induced hypoglycaemia in mothers with type 1 diabetes.

METHODS

Of 43 consecutive mothers with type 1 diabetes, 33 (77%) were included prospectively 1 month after a singleton delivery. Twenty-six mothers (mean [SD] age 30.7 [5.8] years, mean [SD] duration of diabetes 18.6 [10.3] years) were breastfeeding and seven mothers (mean [SD] age 31.7 [5.6] years, mean [SD] duration of diabetes 20.4 [6.2] years) were bottle-feeding their infants with formula. All were experienced in carbohydrate counting using individually tailored insulin therapy with insulin analogues (45% on insulin pump, 55% on multiple daily injections). Thirty-two women with type 1 diabetes, matched for age ±1 year and BMI ±1 kg/m², who had not given birth or breastfed in the previous year, served as a control group. Blinded continuous glucose monitoring (CGM) for 6 days was applied at 1, 2 and 6 months postpartum in the breastfeeding mothers who recorded breastfeeds and carbohydrate intake at each CGM period. CGM was applied at 1 month postpartum in the formula-feeding mothers and once in the control women. The insulin dose was individually tailored after each CGM period.

RESULTS

The percentage of night-time spent with CGM <4.0 mmol/l was low (4.6%, 3.1% and 2.7% at each CGM period in the breastfeeding mothers vs 1.6% in the control women, p = 0.77), and the breastfeeding mothers spent a greater proportion of the night-time in the target range of 4.0-10.0 mmol/l (p = 0.01). Symptomatic hypoglycaemia occurred two or three times per week at 1, 2 and 6 months postpartum in both breastfeeding mothers and the control women. Severe hypoglycaemia was reported by one mother (3%) during the 6 month postpartum period and by one control woman (3%) in the previous year (p = 0.74). In breastfeeding mothers at 1 month, the insulin dose was 18% (-67% to +48%) lower than before pregnancy (p = 0.04). In total, carbohydrate was not consumed in relation to 438 recorded night-time breastfeeds, and CGM <4.0 mmol/l within 3 h occurred after 20 (4.6%) of these breastfeeds.

CONCLUSIONS/INTERPRETATION

The percentage of night-time spent in hypoglycaemia was low in the breastfeeding mothers with type 1 diabetes and was similar in the control women. Breastfeeding at night-time rarely induced hypoglycaemia. The historical recommendation of routine carbohydrate intake at night-time breastfeeding may be obsolete in mothers with type 1 diabetes who have properly reduced insulin dose with sufficient carbohydrate intake.

TRIAL REGISTRATION

ClinicalTrials.gov NCT02898428.