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

American Diabetes Association Professional Practice Committee, ElSayed NA, McCoy RG, Aleppo G, Balapattabi K, Beverly EA, Briggs Early K, Bruemmer D, Echouffo-Tcheugui JB, Ekhlaspour L, Garg R, Khunti K, Lal R, Lingvay I, Matfin G, Pandya N, Pekas EJ, Pilla SJ, Polsky S, Segal AR, Seley JJ, Stanton RC, Bannuru RR. 15. Management of Diabetes in Pregnancy: Standards of Care in Diabetes-2025

The American Diabetes Association (ADA) "Standards of Care in Diabetes" includes the ADA's current clinical practice recommendations and is intended to provide the components of diabetes care, general treatment goals and guidelines, and tools to evaluate quality of care. Members of the ADA Professional Practice Committee, an interprofessional expert committee, are responsible for updating the Standards of Care annually, or more frequently as warranted. For a detailed description of ADA standards, statements, and reports, as well as the evidence-grading system for ADA's clinical practice recommendations and a full list of Professional Practice Committee members, please refer to Introduction and Methodology. Readers who wish to comment on the Standards of Care are invited to do so at professional.diabetes.org/SOC.

Folic Acid Prevents High-Fat Diet-Induced Postpartum Weight Retention in Rats, Which Is Associated with a Reduction in Endoplasmic Reticulum Stress-Mediated Hepatic Lipogenesis

BACKGROUND

Proactively preventing postpartum weight retention (PPWR) is one of the effective intervention strategies to reduce the occurrence of obesity in women. Population studies have shown that serum folate levels are closely related to body weight. The regulation of folic acid on lipid metabolism has been fully confirmed in both in vivo and in vitro studies. For many years, folic acid supplementation has been widely used in periconceptional women due to its role in preventing fetal neural tube defects. However, whether folic acid supplementation prior to and throughout pregnancy exerts preventive effects on PPWR remains uncertain. This study aims to investigate the preventive effect of folic acid on PPWR in rats and further explore the underlying mechanisms.

METHODS

In this study, pregnant rats were administered one of the dietary schedules: control diet (CON), high-fat diet (HF), control diet combined with folic acid (FA) and high-fat diet combined with folic acid (HF + FA).

RESULTS

We discovered that folic acid supplementation inhibited high-fat diet-induced elevations in body weight, visceral fat weight, liver weight, hepatic lipid levels and serum lipid levels at 1 week post-weaning (PW). Western blot analysis showed that folic acid supplementation inhibited the expression of endoplasmic reticulum (ER) stress-specific proteins including GRP78, PERK, eIF2α, IRE1α, XBP1 and ATF6, subsequently decreasing the expression of proteins related to lipid synthesis including SREBP-1c, ACC1 and FAS.

CONCLUSIONS

In conclusion, folic acid supplementation prior to and throughout pregnancy exerts preventive effects on high-fat diet-induced PPWR in rats, and the mechanism is associated with the inhibition of ER stress-mediated lipogenesis signaling pathways in the liver. Folic acid supplementation may serve as a potential strategy for preventing PPWR. In the future, the effectiveness of folic acid in PPWR prevention can be further verified by population studies.

Dietary patterns during pregnancy and maternal and birth outcomes in women with type 1 diabetes: the Environmental Determinants of Islet Autoimmunity (ENDIA) study

AIMS/HYPOTHESIS

Dietary patterns characterised by high intakes of vegetables may lower the risk of pre-eclampsia and premature birth in the general population. The effect of dietary patterns in women with type 1 diabetes, who have an increased risk of complications in pregnancy, is not known. The aim of this study was to investigate the relationship between dietary patterns and physical activity during pregnancy and maternal complications and birth outcomes in women with type 1 diabetes. We also compared dietary patterns in women with and without type 1 diabetes.

METHODS

Diet was assessed in the third trimester using a validated food frequency questionnaire in participants followed prospectively in the multi-centre Environmental Determinants of Islet Autoimmunity (ENDIA) study. Dietary patterns were characterised by principal component analysis. The Pregnancy Physical Activity Questionnaire was completed in each trimester. Data for maternal and birth outcomes were collected prospectively.

RESULTS

Questionnaires were completed by 973 participants during 1124 pregnancies. Women with type 1 diabetes (n=615 pregnancies with dietary data) were more likely to have a 'fresh food' dietary pattern than women without type 1 diabetes (OR 1.19, 95% CI 1.07, 1.31; p=0.001). In women with type 1 diabetes, an increase equivalent to a change from quartile 1 to 3 in 'fresh food' dietary pattern score was associated with a lower risk of pre-eclampsia (OR 0.37, 95% CI 0.17, 0.78; p=0.01) and premature birth (OR 0.35, 95% CI 0.20, 0.62, p<0.001). These associations were mediated in part by BMI and HbA1c. The 'processed food' dietary pattern was associated with an increased birthweight (β coefficient 56.8 g, 95% CI 2.8, 110.8; p=0.04). Physical activity did not relate to outcomes.

CONCLUSIONS/INTERPRETATION

A dietary pattern higher in fresh foods during pregnancy was associated with sizeable reductions in risk of pre-eclampsia and premature birth in women with type 1 diabetes.

Type 1 Diabetes and Pregnancy: Challenges in Glycemic Control and Maternal-Fetal Outcomes

Managing type 1 diabetes during pregnancy presents significant challenges due to physiological and hormonal changes. These factors contribute to major changes in insulin sensitivity, complicating efforts to achieve and sustain optimal blood glucose levels. Poorly controlled glucose levels during pregnancy can result in diabetic embryopathy and elevate the risks of maternal complications such as hypertensive disorders and diabetic ketoacidosis. Fetal complications may include preterm birth, fetal demise, and admission to neonatal intensive care units. It is essential to recognize that there is no universal approach to managing glycemic control in pregnant women with T1DM and care should be individualized. Effective management requires a multidisciplinary approach involving regular monitoring, adjustments in insulin therapy, dietary modifications, and consistent prenatal care. Continuous glucose monitoring has emerged as a valuable tool for real-time glucose monitoring, facilitating tighter glycemic control. Education and support for self-management are important in addressing these challenges. Future developments in technology and personalized approaches to care show promising potential for advancing diabetes management during pregnancy. This provides a comprehensive overview of current literature on the challenges with the management of T1DM during pregnancy, focusing on its impact on maternal and neonatal outcomes and highlighting effective strategies for achieving optimal glycemic control.

A review of CONCEPTT study findings including subanalyses in pregnant women using continuous glucose monitoring with type 1 diabetes and their offspring

The main objective of this article is to provide a comprehensive review of continuous glucose monitor (CGM) use in pregnant women with type 1 diabetes (T1D) from the CONCEPTT study including subanalyses. Literature search was accessed through MEDLINE (1966-September 2023) using the key terms: CONCEPTT, pregnancy, women, T1D, and CGM with limitations set to distinguish human subjects written in English. A total of 17 publications including one main clinical trial and 15 subanalyses have been published to date regarding the use of CGM in pregnant women with T1D which were conducted by a research group identified as the CONCEPTT Collaborative Group. While advances in maternal care have resulted in safer pregnancy for both the mother and child, women with preexisting T1D and pregnancy still experience higher rates of complications both in the short and long term. The use of CGM in pregnancy has not been studied extensively until more recently. The CONCEPTT clinical trial was a landmark study that involved several subanalyses. The main trial proved that CGM use in T1D pregnancy resulted in less hyperglycemia in the third trimester, reduced large for gestational age (LGA, >90th percentile), reduced neonatal intensive care unit admissions lasting longer than 24 h, and reduced neonatal hypoglycemia. Although subanalyses showed a variety of results including 'inconclusive' due to lack of prespecification, it is believed that CGM in T1D during pregnancy is to be recommended and used for overall improved outcomes.

American Diabetes Association Professional Practice Committee, ElSayed NA, Aleppo G, Bannuru RR, Bruemmer D, Collins BS, Ekhlaspour L, Hilliard ME, Johnson EL, Khunti K, Lingvay I, Matfin G, McCoy RG, Perry ML, Pilla SJ, Polsky S, Prahalad P, Pratley RE, Segal AR, Seley JJ, Stanton RC, Gabbay RA. 15. Management of Diabetes in Pregnancy: Standards of Care in Diabetes-2024

The American Diabetes Association (ADA) "Standards of Care in Diabetes" includes the ADA's current clinical practice recommendations and is intended to provide the components of diabetes care, general treatment goals and guidelines, and tools to evaluate quality of care. Members of the ADA Professional Practice Committee, an interprofessional expert committee, are responsible for updating the Standards of Care annually, or more frequently as warranted. For a detailed description of ADA standards, statements, and reports, as well as the evidence-grading system for ADA's clinical practice recommendations and a full list of Professional Practice Committee members, please refer to Introduction and Methodology. Readers who wish to comment on the Standards of Care are invited to do so at professional.diabetes.org/SOC.

15. Management of Diabetes in Pregnancy: Standards of Care in Diabetes-2023

The American Diabetes Association (ADA) "Standards of Care in Diabetes" includes the ADA's current clinical practice recommendations and is intended to provide the components of diabetes care, general treatment goals and guidelines, and tools to evaluate quality of care. Members of the ADA Professional Practice Committee, a multidisciplinary expert committee, are responsible for updating the Standards of Care annually, or more frequently as warranted. For a detailed description of ADA standards, statements, and reports, as well as the evidence-grading system for ADA's clinical practice recommendations and a full list of Professional Practice Committee members, please refer to Introduction and Methodology. Readers who wish to comment on the Standards of Care are invited to do so at professional.diabetes.org/SOC.

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.

Epidemiology and Therapeutic Strategies for Women With Preexisting Diabetes in Pregnancy: How Far Have We Come? The 2021 Norbert Freinkel Award Lecture

The field of diabetes in pregnancy has witnessed tremendous changes over the past 30 years, with an explosive growth in case numbers along with new and exciting opportunities to affect outcomes. Type 1 diabetes in pregnancy has increased by 40%, but type 2 diabetes in pregnancy, rarely seen 30 years ago, has more than doubled and, in some cases, tripled in prevalence. Compared with women with type 2 diabetes, women with type 1 diabetes have higher HbA1c, more large-for-gestational-age infants, and more preterm births. Women with type 2 diabetes have more chronic hypertension, more socioeconomic deprivation, and higher rates of perinatal mortality. Large randomized trials in women with diabetes in pregnancy have helped us understand the effectiveness of new technologies (i.e., continuous glucose monitoring) in women with type 1 diabetes, and the addition of metformin to insulin in women with type 2 diabetes, in improving pregnancy outcomes. Future endeavors, including artificial pancreas systems in women with type 1 diabetes and the use of continuous glucose monitoring, a better understanding of nutrition during pregnancy, and approaches to improve preconception and pregnancy self-care in women with type 2 diabetes, may lead to further improved outcomes.

Reappearance of C-Peptide During the Third Trimester of Pregnancy in Type 1 Diabetes: Pancreatic Regeneration or Fetal Hyperinsulinism?

OBJECTIVE

We assessed longitudinal patterns of maternal C-peptide concentration to examine the hypothesis of β-cell regeneration in pregnancy with type 1 diabetes.

RESEARCH DESIGN AND METHODS

C-peptide was measured on maternal serum samples from 127 participants (12, 24, and 34 weeks) and cord blood during the Continuous Glucose Monitoring in Women With Type 1 Diabetes in Pregnancy Trial (CONCEPTT). C-peptide was measured using a highly sensitive direct and solid-phase competitive electrochemiluminescent immunoassay.

RESULTS

Three discrete patterns of maternal C-peptide trajectory were identified: pattern 1, undetectable throughout pregnancy, n = 74 (58%; maternal C-peptide <3 pmol/L); pattern 2, detectable at baseline, n = 22 (17%; maternal C-peptide 7-272 pmol/L at baseline); and pattern 3, undetectable maternal C-peptide at 12 and 24 weeks, which first became detectable at 34 weeks, n = 31 (24%; maternal C-peptide 4-26 pmol/L at 34 weeks). Baseline characteristics and third trimester glucose profiles of women with pattern 1 and pattern 3 C-peptide trajectories were similar, but women in pattern 3 had suboptimal glycemia (50% time above range) at 24 weeks' gestation. Offspring of women with pattern 3 C-peptide trajectories had elevated cord blood C-peptide (geometric mean 1,319 vs. 718 pmol/L; P = 0.007), increased rates of large for gestational age (90% vs. 60%; P = 0.002), neonatal hypoglycemia (42% vs. 14%; P = 0.001), and neonatal intensive care admission (45% vs. 23%; P = 0.023) compared with pattern 1 offspring.

CONCLUSIONS

First maternal C-peptide appearance at 34 weeks was associated with midtrimester hyperglycemia, elevated cord blood C-peptide, and high rates of neonatal complications. This suggests transfer of C-peptide from fetal to maternal serum and is inconsistent with pregnancy-related β-cell regeneration.

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.

Time trends in pregnancy-related outcomes among women with type 1 diabetes mellitus, 2004-2017

OBJECTIVE

To examine time trends in US pregnant women with type 1 diabetes mellitus for maternal characteristics and pregnancy outcomes.

STUDY DESIGN

We abstracted clinical data from the medical records of 700 pregnant women from 2004 to 2017. For each time period, means and percentages were calculated. P values for trend were calculated using linear and logistic regression.

RESULTS

HbA1c in each trimester was unchanged across the analysis period. The prevalence of nephropathy decreased from 4.8% to 0% (P = 0.002). Excessive gestational weight gain increased (P = 0.01). Gestation length also increased (P = 0.01), as did vaginal deliveries (P = 0.03). There were no change in birthweight over time (P = 0.07) and the percentage of neonates with macrosomia and large for gestational age (LGA) neonates also remained unchanged.

CONCLUSION

Obstetric guideline changes may have improved gestation length and mode of delivery; however, other outcomes need more attention, including excessive gestational weight gain, macrosomia, and LGA.

Diabetes und Schwangerschaft – Update 2020

In einer kurzen Übersicht werden die aktuellen Erkenntnisse zur Coronaviruserkrankung 2019 (COVID-19) bei Schwangeren dargestellt. Selbstmonitoring der kapillaren Blutglukosewerte ist derzeit noch der Goldstandard bei Schwangeren. Bei Verwendung subkutaner Glukosesensoren sollte die „time in range“ (TIR) >70 % in dem Bereich 63–140 mg/dl (3,5–7,8 mmol/l) so früh wie möglich erreicht werden. Bei präexistentem Diabetes besteht bei Kindern mit einer Wachstumsrestriktion ein hohes Risiko für Totgeburten. Mangels nachgewiesener Verbesserung relevanter Endpunkte sollten pharmakologische Therapien bei Schwangeren mit frühem Gestationsdiabetes <24 + 0 Schwangerschaftswochen besonders kritisch abgewogen werden. Präkonzeptionell adipöse Frauen sollten bis zur Geburt nicht mehr als 6 kg zunehmen. Nach bariatrisch-metabolischer Chirurgie bestehen neben Vorteilen für die Mütter erhöhte Risiken für Neugeborene, z. B. eine erhöhte Rate an „small for gestational age“ nach Roux-en-Y-Magenbypass.

Continuous Glucose Monitoring in Pregnancy: Importance of Analyzing Temporal Profiles to Understand Clinical Outcomes

OBJECTIVE

To determine if temporal glucose profiles differed between 1) women who were randomized to real-time continuous glucose monitoring (RT-CGM) or self-monitored blood glucose (SMBG), 2) women who used insulin pumps or multiple daily insulin injections (MDIs), and 3) women whose infants were born large for gestational age (LGA) or not, by assessing CGM data obtained from the Continuous Glucose Monitoring in Women With Type 1 Diabetes in Pregnancy Trial (CONCEPTT).

RESEARCH DESIGN AND METHODS

Standard summary metrics and functional data analysis (FDA) were applied to CGM data from the CONCEPTT trial (RT-CGM, n = 100; SMBG, n = 100) taken at baseline and at 24- and 34-weeks' gestation. Multivariable regression analysis determined if temporal differences in 24-h glucose profiles occurred between comparators in each of the three groups.

RESULTS

FDA revealed that women using RT-CGM had significantly lower glucose (0.4-0.8 mmol/L [7-14 mg/dL]) for 7 h/day (0800 h to 1200 h and 1600 h to 1900 h) compared with those with SMBG. Women using pumps had significantly higher glucose (0.4-0.9 mmol/L [7-16 mg/dL]) for 12 h/day (0300 h to 0600 h, 1300 h to 1800 h, and 2030 h to 0030 h) at 24 weeks with no difference at 34 weeks compared with MDI. Women who had an LGA infant ran a significantly higher glucose by 0.4-0.7 mmol/L (7-13 mg/dL) for 4.5 h/day at baseline, by 0.4-0.9 mmol/L (7-16 mg/dL) for 16 h/day at 24 weeks, and by 0.4-0.7 mmol/L (7-13 mg/dL) for 14 h/day at 34 weeks.

CONCLUSIONS

FDA of temporal glucose profiles gives important information about differences in glucose control and its timing, which are undetectable by standard summary metrics. Women using RT-CGM were able to achieve better daytime glucose control, reducing fetal exposure to maternal glucose.

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.