Elevated third-trimester haemoglobin A 1c predicts preterm delivery in type 1 diabetes

Fetal Overgrowth and Preterm Delivery in Women With Type 1 Diabetes Using Insulin Pumps or Multiple Daily Injections: A Post Hoc Analysis of the EVOLVE Study Cohort

OBJECTIVE

To compare the risk of fetal overgrowth and preterm delivery in pregnant women with type 1 diabetes (T1D) treated with insulin pumps versus multiple daily injections (MDI) and examine whether possible differences were mediated through improved glycemic control or gestational weight gain during pregnancy.

RESEARCH DESIGN AND METHODS

The risk of pregnancy and perinatal outcomes were evaluated in a cohort of 2,003 pregnant women with T1D enrolled from 17 countries in a real-world setting during 2013-2018.

RESULTS

In total, 723 women were treated with pumps and 1,280 with MDI. At inclusion (median gestational weeks 8.6 [interquartile range 7-10]), pump users had lower mean HbA1c (mean ± SD 50.6 ± 9.8 mmol/mol [6.8 ± 0.9%] vs. 53.6 ± 13.8 mmol/mol [7.1 ± 1.3%], P < 0.001), longer diabetes duration (18.4 ± 7.8 vs. 14.4 ± 8.2 years, P < 0.001), and higher prevalence of retinopathy (35.3% vs. 24.4%, P < 0.001). Proportions of large for gestational age (LGA) offspring and preterm delivery were 59.0% vs. 52.2% (adjusted odds ratio [OR] 1.36 [95% CI 1.09; 1.70], P = 0.007) and 39.6% vs. 32.1% (adjusted OR 1.46 (95% CI 1.17; 1.82), P < 0.001), respectively. The results did not change after adjustment for HbA1c or gestational weight gain.

CONCLUSIONS

Insulin pump treatment in pregnant women with T1D, prior to the widespread use of continuous glucose monitoring or automated insulin delivery, was associated with a higher risk of LGA offspring and preterm delivery compared with MDI in crude and adjusted analyses. This association did not appear to be mediated by differences in glycemic control as represented by HbA1c or by gestational weight gain.

Congenital malformations among offspring of women with type 1 diabetes who use insulin pumps: a prospective cohort study

AIMS/HYPOTHESIS

Continuous subcutaneous insulin infusion by insulin pump is often superior in improving glycaemic control compared with conventional multiple daily insulin injection (MDI). However, whether pump treatment leads to improved pregnancy outcomes in terms of congenital malformations and perinatal death remains unknown. The present aim was to evaluate the risk of malformations and perinatal and neonatal death in pregnant women with type 1 diabetes treated with pump or MDI.

METHODS

We performed a secondary analysis of a prospective multinational cohort of 2088 pregnant women with type 1 diabetes in a real-world setting who were treated by pump (n=750) or MDI (n=1338). ORs for offspring with congenital malformations or perinatal or neonatal death were calculated using crude data and by logistic regression on propensity score-matched data.

RESULTS

At enrolment (gestational week 8; 95% CI 4, 14), pump users had a higher educational level (university degree: 37.3% vs 25.1%; p<0.001) and better glycaemic control (mean HbA1c: 51±10 mmol/mol [6.8±0.9%] vs 54±14 mmol/mol [7.1±1.3%], p<0.001) compared with MDI users. Moreover, a greater proportion of pump users had an HbA1c level below 75 mmol/mol (9%) (97.6% vs 91.9%, p<0.001), and more often reported taking folic acid supplementation (86.3% vs 74.8%; p<0.001) compared with MDI users. All clinically important potential confounders were balanced after propensity score matching, and HbA1c remained lower in pump users. The proportion of fetuses with at least one malformation was 13.5% in pump users vs 11.2% in MDI users (crude OR 1.23; 95% CI 0.94, 1.61; p=0.13; propensity score-matched (adjusted) OR 1.11; 95% CI 0.81, 1.52; p=0.52). The proportion of fetuses with at least one major malformation was 2.8% in pump users vs 3.1% in MDI users (crude OR 0.89; 95% CI 0.52, 1.51; p=0.66; adjusted OR 0.78; 95% CI 0.42, 1.45; p=0.43), and the proportions of fetuses carrying one or more minor malformations (but no major malformations) were 10.7% vs 8.1% (crude OR 1.36; 95% CI 1.00, 1.84; p=0.05; adjusted OR 1.23; 95% CI 0.87, 1.75; p=0.25). The proportions of perinatal and neonatal death were 1.6% vs 1.3% (crude OR 1.23; 95% CI 0.57, 2.67; p=0.59; adjusted OR 2.02; 95% CI 0.69, 5.93; p=0.20) and 0.3% vs 0.3% (n=2 vs n=4, p=not applicable), respectively.

CONCLUSIONS/INTERPRETATIONS

Insulin pump treatment was not associated with a lower risk of congenital malformations, despite better glycaemic control in early pregnancy compared with MDI. Further studies exploring the efficacy and safety of pump treatment during pregnancy are needed.

Infants with macrosomia and infants of diabetic mothers have increased carotid artery intima-media thickness in childhood

Incidence of diabetes during pregnancy is increasing worldwide, and intrauterine hyperglycemia exposure may have long-term adverse effects on the cardiovascular health of children. We investigated prospectively the risk of atherosclerosis and carotid intima-media thickness (CIMT) in infants born macrosomic and in infants of diabetic mothers (IDM) at the age of 8-9 years in 2021. A total of 49 infants of diabetic mothers (IDM group) and 13 macrosomic infants (macrosomic group) were included in the study. They were compared with 26 age-matched healthy children with birth weight appropriate for gestational age born to non-diabetic mothers (control group). Anthropometric measurements, atherosclerosis risk factors, and CIMT measurements were performed. There was no significant difference between the groups in terms of age, gender, actual anthropometric measurements, blood pressure measurements, laboratory parameters, or atherosclerosis risk factors. Gestational age was lower in the IDM group (p < 0.001), while birth weight was higher in the macrosomic group (p < 0.001). High-density lipoprotein cholesterol level was lower in the IDM group than the other groups. Duration of exclusive and total breastfeeding was lower in IDM group than in the control group (p < 0.001 for both). Body mass index, skinfold thickness, waist-to-hip ratio, and waist-to-height ratio were higher in those breastfed for less than 6 months in the IDM group. The CIMT values were statistically higher in IDM [0.43 ± 0.047 (0.34-0.60)] and macrosomic [0.40 ± 0.055 (0.33-0.50)] groups than control group [0.34 ± 0.047 (0.26-0.45)].

CONCLUSION

CIMT values were higher in IDM and macrosomic groups at 8-9 years old age compared to children born with normal birth weight. This indicates intrauterine exposure in both groups. And also, breastfeeding seems very important for IDMs.

WHAT IS KNOWN

• Intrauterine hyperglycemia exposure has long-term adverse effects on the cardiovascular health of children. • Infants of diabetic mothers have higher carotid artery intima-media thickness at birth.

WHAT IS NEW

• Both infants of diabetic mothers and infants with macrosomia have increased carotid artery intima-media thickness at the age of 8-9 years. • Duration of breast feeding is important especially in infants of diabetic mothers as body mass index, skinfold thickness, waist to hip and height ratio were higher in those breastfed less than 6 months.

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.

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

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

Comparison of Glycemic Metrics Measured Simultaneously by Intermittently Scanned Continuous Glucose Monitoring and Real-Time Continuous Glucose Monitoring in Pregnant Women with Type 1 Diabetes

Background: We aimed to compare clinically important glycemic metrics with focus on mean sensor glucose and time-below-target range (TBR) during nighttime obtained with intermittently scanned continuous glucose monitoring (isCGM) and real-time CGM (rtCGM) in early pregnancy in women with type 1 diabetes. Materials and Methods: A prospective, observational study including 20 women with type 1 diabetes simultaneously monitored with isCGM (Freestyle Libre; Abbott) and rtCGM (Envision™ Pro; Medtronic) for 7 days in early pregnancy. Time-in-target range (TIR) was defined as 3.5-7.8 mmol/L. Results: Gestational age was median 66 (interquartile range 63-74) days and HbA1c was 48 mmol/mol (43-54). Median difference between isCGM and rtCGM was 0.1 mmol/L (-0.1 to 0.5) (P = 0.50) and -0.1 mmol/L (-0.4 to 0.2) (P = 0.35) for 24 h and during nighttime, respectively. For 24 h, TBR was 3.9% (1.6-7.0) versus 2.0% (0.6-3.7) (P = 0.06) and TIR was 57.2% (50.8-76.5) versus 69.6% (55.4-81.5) (P = 0.001) for isCGM and rtCGM, respectively. During nighttime TBR was 6.5% (0.4-16.7) versus 0% (0.0-0.8) (P = 0.003), TIR was 55.4 (41.1-81.0) versus 68.8 (52.4-80.3) (P = 0.005) and 75% versus 40% of the women had ≥1 glucose reading <3.5 mmol/L. Conclusions: In pregnant women with type 1 diabetes, mean sensor glucose was reported similar when measured by isCGM and rtCGM. However, during nighttime isCGM measured a clinically relevant higher percentage of TBR compared with rtCGM. Thus, the type of CGM device used may influence adjustments of insulin dose based on the concern for nocturnal hypoglycemia. ClinicalTrials.gov (NCT03770767).

Potentially modifiable risk factors of preterm delivery in women with type 1 and type 2 diabetes

AIMS/HYPOTHESIS

We aimed to identify potentially modifiable risk factors and causes for preterm delivery in women with type 1 or type 2 (pre-existing) diabetes.

METHODS

A secondary analysis of a prospective cohort study of 203 women with pre-existing diabetes (117 type 1 and 86 type 2 diabetes) was performed. Consecutive singleton pregnancies were included at the first antenatal visit between September 2015 and February 2018.

RESULTS

In total, 27% (n = 55) of the 203 women delivered preterm at median 36 + 0 weeks. When stratified by diabetes type, 33% of women with type 1 diabetes delivered preterm compared with 20% in women with type 2 diabetes (p = 0.04). Women delivering preterm were characterised by a higher prevalence of pre-existing kidney involvement (microalbuminuria or diabetic nephropathy) (16% vs 3%, p = 0.002), preeclampsia (26% vs 5%, p < 0.001), higher positive ultrasound estimated fetal weight deviation at 27 gestational weeks (2.7% vs -1.6% from the mean, p = 0.008), higher gestational weight gain (399 g/week vs 329 g/week, p = 0.01) and similar HbA_1c levels in early pregnancy (51 mmol/mol [6.8%] vs 49 [6.6%], p = 0.22) when compared with women delivering at term. Independent risk factors for preterm delivery were pre-existing kidney involvement (OR 12.71 [95% CI 3.0, 53.79]), higher gestational weight gain (per 100 g/week, OR 1.25 [1.02, 1.54]), higher positive ultrasound estimated fetal weight deviation at 27 gestational weeks (% from the mean, OR 1.07 [1.03, 1.12]) and preeclampsia (OR 7.04 [2.34, 21.19]). Two-thirds of preterm deliveries were indicated and one-third were spontaneous. Several contributing factors to indicated preterm delivery were often present in each woman. The main indications were suspected fetal asphyxia (45%), hypertensive disorders (34%), fetal overgrowth (13%) and maternal indications (8%). Suspected fetal asphyxia mainly included falling insulin requirement and abnormal fetal haemodynamics.

CONCLUSIONS/INTERPRETATIONS

Presence of preeclampsia, higher positive ultrasound estimated fetal weight deviation at 27 gestational weeks and higher gestational weight gain were independent potentially modifiable risk factors for preterm delivery in this cohort of women with pre-existing diabetes. Indicated preterm delivery was common with suspected fetal asphyxia or preeclampsia as the most prevalent causes. Prospective studies evaluating whether modifying these predictors will reduce the prevalence of preterm delivery are warranted.

Novel Biochemical Markers of Glycemia to Predict Pregnancy Outcomes in Women With Type 1 Diabetes

OBJECTIVE

The optimal method of monitoring glycemia in pregnant women with type 1 diabetes remains controversial. This study aimed to assess the predictive performance of HbA_1c, continuous glucose monitoring (CGM) metrics, and alternative biochemical markers of glycemia to predict obstetric and neonatal outcomes.

RESEARCH DESIGN AND METHODS

One hundred fifty-seven women from the Continuous Glucose Monitoring in Women With Type 1 Diabetes in Pregnancy Trial (CONCEPTT) were included in this prespecified secondary analysis. HbA_1c, CGM data, and alternative biochemical markers (glycated CD59, 1,5-anhydroglucitol, fructosamine, glycated albumin) were compared at ∼12, 24, and 34 weeks' gestation using logistic regression and receiver operating characteristic (ROC) curves to predict pregnancy complications (preeclampsia, preterm delivery, large for gestational age, neonatal hypoglycemia, admission to neonatal intensive care unit).

RESULTS

HbA_1c, CGM metrics, and alternative laboratory markers were all significantly associated with obstetric and neonatal outcomes at 24 weeks' gestation. More outcomes were associated with CGM metrics during the first trimester and with laboratory markers (area under the ROC curve generally <0.7) during the third trimester. Time in range (TIR) (63-140 mg/dL [3.5-7.8 mmol/L]) and time above range (TAR) (>140 mg/dL [>7.8 mmol/L]) were the most consistently predictive CGM metrics. HbA_1c was also a consistent predictor of suboptimal pregnancy outcomes. Some alternative laboratory markers showed promise, but overall, they had lower predictive ability than HbA_1c.

CONCLUSIONS

HbA_1c is still an important biomarker for obstetric and neonatal outcomes in type 1 diabetes pregnancy. Alternative biochemical markers of glycemia and other CGM metrics did not substantially increase the prediction of pregnancy outcomes compared with widely available HbA_1c and increasingly available CGM metrics (TIR and TAR).

"High prepregnancy HbA1c is challenging to improve and affects insulin requirements, gestational length, and birthweight"

BACKGROUND

The aim of this study was to explore how prepregnancy glycosylated hemoglobin (HbA1c) affects the course of HbA1c and insulin requirements during pregnancy, the gestational length, and birthweight.

METHODS

An observational cohort study was conducted consisting of 380 women with type 1 diabetes who gave birth 530 times from 2004 to 2014. The participants were divided into four groups according to prepregnancy HbA1c.

RESULTS

HbA1c was significantly different between the groups at all time intervals from week 5 to 10 to week 33 to 36 (P ≤ .01). In group 1, with the lowest prepregnancy HbA1c (<6.5% [48 mmol/mol]), HbA1c stayed at the same level throughout pregnancy. In the other groups (group 2: 6.5% [48 mmol/mol]-7.9% [63 mmol/mol], group 3: 8% [64 mmol/mol]-9.9% [86 mmol/mol], and group 4: > 10% [86 mmol/mol]) a decrease in HbA1c was seen in early pregnancy but stabilized from midpregnancy onward. Group 1 had the lowest daily insulin requirements throughout pregnancy among the four groups (P = .001). The relationship between birthweight and prepregnancy HbA1c was found to be inversely U-shaped. Mean gestational length in group 4 was significantly shorter than in group 1 (P = .001).

CONCLUSIONS

In this very large cohort, we found that a poor prepregnancy HbA1c is a predictor for poor glycemic control during pregnancy and that HbA1c decreases until midpregnancy and then plateaus. A very poor prepregnancy HbA1c is associated with shorter gestational length and lower birthweight, which is contrary to the common assumption that poor glycemic control leads to higher birthweight.

Preeclampsia and other pregnancy outcomes in nulliparous women with type 1 diabetes: a retrospective survey

Obstetric complications are more common in women with diabetes than in the general population. This study aimed to learn about the first pregnancy of women with type 1 diabetes from the perspective of women from T1D Exchange-Glu and the T1D Exchange Clinic Registry. Participants were ≥18, diagnosed with type 1 diabetes before conception, and either currently pregnant or had given birth in the preceding 10 years. The final sample size was 533 women. Women who planned pregnancy had significantly lower HbA1c (A1c) at conception. Women who had higher A1cs at conception were at a higher risk for cesarean birth, increased weight gain, hypoglycemia during pregnancy, and earlier onset of preeclampsia. Overall 29% of women developed preeclampsia in this population, over seven times the rate in the general population. This study helps to expand our knowledge of women with type 1 diabetes during the perinatal period. Planning pregnancy, expanding education and support, and preventing preeclampsia may help to improve pregnancy outcomes.

Leveraging technology for the treatment of type 1 diabetes in pregnancy: A review of past, current, and future therapeutic tools

The significant risks associated with pregnancies complicated by type 1 diabetes (T1D) were first recognized in the medical literature in the mid-twentieth century. Stringent glycemic control with hemoglobin A1c (HbA1c) values ideally less than 6% has been shown to improve maternal and fetal outcomes. The management options for pregnant women with T1D in the modern era include a variety of technologies to support self-care. Although self-monitoring of blood glucose (SMBG) and multiple daily injections (MDI) are often the recommended management options during pregnancy, many people with T1D utilize a variety of different technologies, including continuous glucose monitoring (CGM), continuous subcutaneous insulin infusion (CSII), and CSII including automated delivery or suspension algorithms. These systems have yielded invaluable diagnostic and therapeutic capabilities and have the potential to benefit this understudied higher-risk group. A recent prospective, multicenter study evaluating pregnant patients with T1D revealed that CGM significantly improves maternal glycemic parameters, is associated with fewer adverse neonatal outcomes, and minimizes burden. Outcome data for CSII, which is approved for use in pregnancy and has been utilized for several decades, remain mixed. Current evidence, although limited, for commercially available and emerging technologies for the management of T1D in pregnancy holds promise for improving patient and fetal outcomes.

Need for less tight glucose control in early pregnancy after embryogenesis due to high risk of maternal hypoglycaemia in women with pre-existing diabetes can be compensated by good control in late pregnancy

AIM

Poor glucose control is associated with adverse outcomes in pregnancies with pre-existing diabetes. However, strict glucose control increases the risk of severe hypoglycaemia, particularly in the first trimester. Therefore, we aimed to investigate whether less tight glucose control in the first trimester determines adverse outcomes or can be compensated for by good control in late pregnancy.

METHODS

Retrospective data were collected from 517 singleton pregnancies complicated by pre-existing diabetes delivering between 2010 and 2017. Three hundred and thirty-six pregnancies fulfilled the inclusion criteria of having available HbA_1c values either pre-conception or in the first trimester (65% type 1 diabetes, 35% type 2 diabetes).

RESULTS

Higher HbA_1c values in the first trimester were associated with increasing rates of large for gestational age (LGA) neonates, preterm delivery or neonatal intensive care unit admissions. Multiple regression analysis demonstrated third trimester HbA_1c , type 1 diabetes, multiparity and excess weight gain, but not first trimester HbA_1c , to be independently predictive for LGA. Pre-eclampsia and third trimester HbA_1c increased the risk for preterm delivery. If HbA_1c was ≤ 42 mmol/mol (6.0%) in the third trimester, rates of adverse outcomes were not significantly higher even if HbA_1c targets of ≤ 48 mmol/mol (6.5%) had not been met in the first trimester. Good first trimester glucose control did not modify the rates of adverse outcomes if HbA_1c was > 42 mmol/mol (6.0%) in the third trimester.

CONCLUSIONS

Less tight glycaemic control, for example due to high frequency of severe hypoglycaemia in the first trimester, does not lead to increased adverse neonatal events if followed by tight control in the third trimester. Besides glycaemic control, excess weight gain is a modifiable predictor of adverse outcome.

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.

Maternal Glycemic Control in Type 1 Diabetes and the Risk for Preterm Birth: A Population-Based Cohort Study

BACKGROUND

Maternal type 1 diabetes (T1D) has been linked to preterm birth and other adverse pregnancy outcomes. How these risks vary with glycated hemoglobin (or hemoglobin A1c [HbA1c]) levels is unclear.

OBJECTIVE

To examine preterm birth risk according to periconceptional HbA1c levels in women with T1D.

DESIGN

Population-based cohort study.

SETTING

Sweden, 2003 to 2014.

PATIENTS

2474 singletons born to women with T1D and 1 165 216 reference infants born to women without diabetes.

MEASUREMENTS

Risk for preterm birth (<37 gestational weeks). Secondary outcomes were neonatal death, large for gestational age, macrosomia, infant birth injury, hypoglycemia, respiratory distress, 5-minute Apgar score less than 7, and stillbirth.

RESULTS

Preterm birth occurred in 552 (22.3%) of 2474 infants born to mothers with T1D versus 54 287 (4.7%) in 1 165 216 infants born to mothers without diabetes. The incidence of preterm birth was 13.2% in women with a periconceptional HbA1c level below 6.5% (adjusted risk ratio [aRR] vs. women without T1D, 2.83 [95% CI, 2.28 to 3.52]), 20.6% in those with a level from 6.5% to less than 7.8% (aRR, 4.22 [CI, 3.74 to 4.75]), 28.3% in those with a level from 7.8% to less than 9.1% (aRR, 5.56 [CI, 4.84 to 6.38]), and 37.5% in those with a level of 9.1% or higher (aRR, 6.91 [CI, 5.85 to 8.17]). The corresponding aRRs for medically indicated preterm birth (n = 320) were 5.26 (CI, 3.83 to 7.22), 7.42 (CI, 6.21 to 8.86), 11.75 (CI, 9.72 to 14.20), and 17.51 (CI, 14.14 to 21.69), respectively. The corresponding aRRs for spontaneous preterm birth (n = 223) were 1.81 (CI, 1.31 to 2.52), 2.86 (CI, 2.38 to 3.44), 2.88 (CI, 2.23 to 3.71), and 2.80 (CI, 1.94 to 4.03), respectively. Increasing HbA1c levels were associated with the study's secondary outcomes: large for gestational age, hypoglycemia, respiratory distress, low Apgar score, neonatal death, and stillbirth.

LIMITATION

Because HbA1c levels were registered annually at routine visits, they were not available for all pregnant women with T1D.

CONCLUSION

The risk for preterm birth was strongly linked to periconceptional HbA1c levels. Women with HbA1c levels consistent with recommended target levels also were at increased risk.

PRIMARY FUNDING SOURCE

Swedish Diabetes Foundation.

The Utility of Lower Glycemic Targets for Treating Gestational Diabetes: A Retrospective Study

OBJECTIVE

In vivo study of glucose homeostasis in pregnancy suggests normal glucose levels are lower than current glycemic targets used in gestational diabetes. After the HAPO study results, our institution began using glycemic targets of fasting 85 mg/dL and 2-hour postprandial of 110 mg/dL. We reviewed our results.

METHODS

A retrospective cohort of GDM patients that delivered at KUMC from January 2007 to May 2017 was reviewed. All patients were diagnosed with the 2-step Carpenter-Coustan thresholds. High targets were compared with low targets. The primary outcome investigated was birthweight > 90% (large for gestational age, LGA).

RESULTS

604 patients were studied, and 34% were treated with low glycemic targets. Our unadjusted results showed that the low-target group had a lower incidence of LGA infants (24.0 vs. 31.8%), higher incidence of neonatal hypoglycemia (20.7 vs. 11.6%), and inductions (39.4 vs. 20.5%). After adjustment for demographic variables, only a higher risk of inductions remained (aOR 2.54 (1.44, 4.49)).

CONCLUSION

Lower glycemic targets did not produce large reductions in fetal overgrowth, but they were associated with a higher rate of inductions. As there were no observed differences in maternal or neonatal outcomes otherwise, aiming for lower glycemic targets in GDM is likely not cost-effective.

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.

Pregnancy Outcomes in Women With Diabetes-Lessons Learned From Clinical Research: The 2015 Norbert Freinkel Award Lecture

Among women with diabetes, the worst pregnancy outcome is seen in the subgroup of women with diabetic nephropathy. Development of severe preeclampsia that leads to early preterm delivery is frequent. Predictors and pathophysiological mechanisms for the development of preeclampsia among women with diabetes and observational studies that support antihypertension treatment for pregnant women with microalbuminuria or diabetic nephropathy preventing preeclampsia and early preterm delivery are presented here. Obtaining and maintaining strict glycemic control before and during pregnancy is paramount to prevent preterm delivery. The cornerstones of diabetes management are appropriate diet and insulin, although the risk of severe hypoglycemia always needs to be taken into account when tailoring a diabetes treatment plan. Pathophysiological mechanisms of the increased risk of hypoglycemia during pregnancy are explored, and studies evaluating the use of insulin analogs, insulin pumps, and continuous glucose monitoring to improve pregnancy outcomes and to reduce the risk of severe hypoglycemia in pregnant women with type 1 diabetes are reported. In addition to strict glycemic control, other factors involved in fetal overgrowth are explored, and restricting maternal gestational weight gain is a promising treatment area. The optimal carbohydrate content of the diet is discussed. In summary, the lessons learned from this clinical research are that glycemic control, gestational weight gain, and antihypertension treatment all are of importance for improving pregnancy outcomes in pregnant women with preexisting diabetes. An example of how to use app technology to share the recent evidence-based clinical recommendations for women with diabetes who are pregnant or planning pregnancy is given.

Glycemic targets in the second and third trimester of pregnancy for women with type 1 diabetes

OBJECTIVE

To assess the relationship between second and third trimester glycemic control and adverse outcomes in pregnant women with type 1 diabetes, as uncertainty exists about optimum glycemic targets.

RESEARCH DESIGN AND METHODS

Pregnancy outcomes were assessed prospectively in 725 women with type 1 diabetes from the Diabetes and Pre-eclampsia Intervention Trial. HbA1c (A1C) values at 26 and 34 weeks' gestation were categorized into five groups, the lowest, <6.0% (42 mmol/mol), being the reference. Average pre- and postprandial results from an eight-point capillary glucose profile the previous day were categorized into five groups, the lowest (preprandial <5.0 mmol/L and postprandial <6.0 mmol/L) being the reference.

RESULTS

An A1C of 6.0-6.4% (42-47 mmol/mol) at 26 weeks' gestation was associated with a significantly increased risk of large for gestational age (LGA) (odds ratio 1.7 [95% CI 1.0-3.0]) and an A1C of 6.5-6.9% (48-52 mmol/mol) with a significantly increased risk of preterm delivery (odds ratio 2.5 [95% CI 1.3-4.8]), pre-eclampsia (4.3 [1.7-10.8]), need for a neonatal glucose infusion (2.9 [1.5-5.6]), and a composite adverse outcome (3.2 [1.3-8.0]). These risks increased progressively with increasing A1C. Results were similar at 34 weeks' gestation. Glucose data showed less consistent trends, although the risk of a composite adverse outcome increased with preprandial glucose levels between 6.0 and 6.9 mmol/L at 34 weeks (3.3 [1.3-8.0]).

CONCLUSIONS

LGA increased significantly with an A1C ≥6.0 (42 mmol/mol) at 26 and 34 weeks' gestation and with other adverse outcomes with an A1C ≥6.5% (48 mmol/mol). The data suggest that there is clinical utility in regular measurement of A1C during pregnancy.

Higher gestational weight gain is associated with increasing offspring birth weight independent of maternal glycemic control in women with type 1 diabetes

OBJECTIVE

We evaluate the association between gestational weight gain and offspring birth weight in singleton term pregnancies of women with type 1 diabetes.

RESEARCH DESIGN AND METHODS

One hundred fifteen consecutive women referred at <14 weeks were retrospectively classified as underweight (prepregnancy BMI <18.5 kg/m(2); n = 1), normal weight (18.5-24.9; n = 65), overweight (25.0-29.9; n = 39), or obese (≥30.0; n = 10). Gestational weight gain was categorized as excessive, appropriate, or insufficient according to the Institute of Medicine recommendations for each BMI class. Women with nephropathy, preeclampsia, and/or preterm delivery were excluded because of restrictive impact on fetal growth and limited time for total weight gain.

RESULTS

HbA1c was comparable at ∼6.6% (49 mmol/mol) at 8 weeks and ∼6.0% (42 mmol/mol) at 36 weeks between women with excessive (n = 62), appropriate (n = 37), and insufficient (n = 16) gestational weight gain. Diabetes duration was comparable, and median prepregnancy BMI was 25.3 (range 18-41) vs. 23.5 (18-31) vs. 22.7 (20-30) kg/m(2) (P = 0.05) in the three weight gain groups. Offspring birth weight and birth weight SD score decreased across the groups (3,681 [2,374-4,500] vs. 3,395 [2,910-4,322] vs. 3,295 [2,766-4,340] g [P = 0.02] and 1.08 [-1.90 to 3.25] vs. 0.45 [-0.83 to 3.18] vs. -0.02 [-1.51 to 2.96] [P = 0.009], respectively). In a multiple linear regression analysis, gestational weight gain (kg) was positively associated with offspring birth weight (g) (β = 19; P = 0.02) and birth weight SD score (β = 0.06; P = 0.008) when adjusted for prepregnancy BMI, HbA1c at 36 weeks, smoking, parity, and ethnicity.

CONCLUSIONS

Higher gestational weight gain in women with type 1 diabetes was associated with increasing offspring birth weight independent of glycemic control and prepregnancy BMI.

Can hemoglobin A1c in early pregnancy predict adverse pregnancy outcomes in diabetic patients?

OBJECTIVE

To examine the association of elevated early pregnancy hemoglobin A1c (HbA1c) levels with adverse pregnancy outcomes in women with preexisting diabetes mellitus.

STUDY DESIGN

Retrospective cohort study of 330 women with preexisting diabetes enrolled in a Diabetes in Pregnancy Program at an academic institution between 2003 and 2011 who had an early HbA1c determination. The frequencies of composite maternal adverse pregnancy outcomes (birth at<37 weeks, preeclampsia, and medically indicated birth <39 weeks), and composite fetal adverse pregnancy outcomes [shoulder dystocia, Apgar scores<7 at 5 minutes, small for gestational age (SGA), large for gestational age (LGA), and stillbirth] were compared between HbA1c categories (<6.5, 6.5-7.4, 7.5-8.4 and ≥ 8.5%).

RESULTS

There was no statistically significant difference between composite adverse maternal pregnancy outcomes and composite adverse fetal pregnancy outcomes as well as other individual outcomes between different HbA1c categories. Of the vaginally delivered women in our cohort, the 37 patients with HbA1c levels of ≥ 8.5% had a significantly higher frequency of fetal shoulder dystocia than the 62 with HbA1c levels of < 8.5% (24.2 vs. 1.6%, P = 0.002). Neonates of patients with HbA1c ≥ 8.5% were more likely to have low five minute Apgar scores than neonates of patients with HbA1c < 8.5%, but this was of borderline statistical significance (7.4% vs. 0.5%, P = 0.05).

CONCLUSION

In patients with preexisting diabetes mellitus, HbA1c levels of ≥ 8.5% during early pregnancy are not useful in predicting most adverse outcomes, although there may be an increased risk for shoulder dystocia.

Pregnancy in women with type 1 diabetes: have the goals of St. Vincent declaration been met concerning foetal and neonatal complications?

OBJECTIVE

In 1989 the St. Vincent declaration set a five-year target for approximating outcomes of pregnancies in women with diabetes to those of the background population. We investigated and quantified the risk of adverse pregnancy outcomes in pregnant women with type 1 diabetes (T1DM) to evaluate if the goals of the 1989 St. Vincent Declaration have been obtained concerning foetal and neonatal complications.

METHODS

Twelve population-based studies published within the last 10 years with in total 14,099 women with T1DM and 4,035,373 women from the background population were identified. The prevalence of four foetal and neonatal complications was compared.

RESULTS

In women with T1DM versus the background population, congenital malformations occurred in 5.0% (2.2-9.0) (weighted mean and range) versus 2.1% (1.5-2.9), relative risk (RR) = 2.4, perinatal mortality in 2.7% (2.0-6.6) versus 0.72% (0.48-0.9), RR = 3.7, preterm delivery in 25.2% (13.0-41.7) versus 6.0% (4.7-7.1), RR = 4.2 and delivery of large for gestational infants in 54.2% (45.1-62.5) versus 10.0%, RR = 4.5. Early pregnancy HbA1c was positively associated with adverse pregnancy outcomes.

CONCLUSION

The risk of adverse pregnancy outcomes was two to five times increased in women with T1DM compared with the general population. The goals of the St. Vincent declaration have not been achieved.

Hypoglycaemia during pregnancy in women with Type 1 diabetes

AIMS

To explore incidence, risk factors, possible pathophysiological factors and clinical management of hypoglycaemia during pregnancy in women with Type 1 diabetes.

METHODS

Literature review.

RESULTS

In women with Type 1 diabetes, severe hypoglycaemia occurs three to five times more frequently in early pregnancy than in the period prior to pregnancy, whereas in the third trimester the incidence of severe hypoglycaemia is lower than in the year preceding pregnancy. The frequency distribution of severe hypoglycaemia is much skewed, as 10% of the pregnant women account for 60% of all recorded events. Risk factors for severe hypoglycaemia during pregnancy include a history with severe hypoglycaemia in the year preceding pregnancy, impaired hypoglycaemia awareness, long duration of diabetes, low HbA(1c) in early pregnancy, fluctuating plasma glucose values (≤ 3.9 mmol/l or ≥ 10.0 mmol/l) and excessive use of supplementary insulin injections between meals. Pregnancy-induced nausea and vomiting seem not to be contributing factors.

CONCLUSIONS

Striving for near-normoglycaemia with focus on reduction of plasma glucose fluctuations during pregnancy should have high priority among clinicians with the persistent aim of improving pregnancy outcome among women with Type 1 diabetes. Pre-conception counselling, carbohydrate counting, use of insulin analogues, continuous subcutaneous insulin infusion (insulin pump) therapy and real-time continuous glucose monitoring with alarms for low glucose values might be relevant tools to obtain near-normoglycaemia without episodes of severe hypoglycaemia.

Stillbirth in diabetic pregnancies

Pregnancy in women with pregestational diabetes is associated with high perinatal morbidity and mortality. Stillbirth accounts for the majority of cases with perinatal death. Intrauterine growth restriction, pre-eclampsia, foetal hypoxia and congenital malformations may be contributing factors, but more than 50% of stillbirths are unexplained. Majority of stillbirths are characterised by suboptimal glycaemic control during pregnancy. Foetal hypoxia and cardiac dysfunction secondary to poor glycaemic control are probably the most important pathogenic factors in stillbirths among pregnant diabetic women. There is thus a need for new strategies for improving glycaemic control to near-normal levels throughout pregnancy and for preventing and treating hypertensive disorders in pregnancy. Antenatal surveillance tests including ultrasound examinations of the foetal growth rate, kick counting and non-stress testing of foetal cardiac function are widely used. However, future research should establish better antenatal surveillance tests to identify the infants susceptible to stillbirth before it happens.

Diabetic mothers and their newborn infants - rooming-in and neonatal morbidity

AIM

As a result of increased neonatal morbidity, the infants of diabetic mothers have routinely been admitted to a neonatal special care unit (NSCU). We therefore investigated whether the offer of rooming-in diabetic mothers and their newborn infants has an effect on neonatal morbidity.

METHODS

The records of an old cohort of 103 infants routinely admitted to the NSCU, and a new cohort (N = 102), offered rooming-in were assessed for neonatal morbidity.

RESULTS

Eighty-four (82%) of the new cohort infants followed their mothers to the maternity ward; whereas 19 (18%) were transferred to the NSCU chiefly because of prematurity. Ten infants were later transferred to the NSCU for minor problems. Neonatal morbidity and neonatal hypoglycaemia were significantly less common in the new cohort than in the old cohort [27 (26%) vs. 55 (54%), p < 0.001 and 42 (41%) vs. 64 (63%), p = 0.0027 respectively]. Maternal HbA1c in late pregnancy was significantly lower in the new cohort, but the only independent predictors of neonatal morbidity were belonging to the old cohort and preterm delivery.

CONCLUSION

Neonatal care with rooming-in mothers with type 1 diabetes and their newborn infants seems safe and is associated with reduced neonatal morbidity, when compared with routine separation of infants from their mothers.

Glucose monitoring during pregnancy

Self-monitoring of blood glucose in women with mild gestational diabetes has recently been proven to be useful in reducing the rates of fetal overgrowth and gestational weight gain. However, uncertainty remains with respect to the optimal frequency and timing of self-monitoring. A continuous glucose monitoring system may have utility in pregnant women with insulin-treated diabetes, especially for those women with blood sugars that are difficult to control or who experience nocturnal hypoglycemia; however, continuous glucose monitoring systems need additional study as part of larger, randomized trials.

Progression of diabetic retinopathy during pregnancy in women with type 2 diabetes

AIMS/HYPOTHESIS

We studied the progression of diabetic retinopathy during pregnancy in women with type 2 diabetes.

METHODS

Fundus photography was performed at median 10 (range 6-21) and 28 (27-37) gestational weeks in 80 of 110 (73%) consecutively referred pregnant women with type 2 diabetes. Diabetic retinopathy was classified in five stages. Progression was defined as at least one stage of deterioration of diabetic retinopathy and/or development of macular oedema on at least one eye between the two examinations. Macular oedema was defined as retinal thickening and/or hard exudates within a diameter of 1,500 microm in the macula area.

RESULTS

Diabetic retinopathy, mainly mild, was present in 11 (14%) women in early pregnancy. Median duration of diabetes was 3 years (range 0-16 years). At baseline, HbA(1c) was 6.4% (1.0) (mean [SD]), systolic BP 121 (13) and diastolic BP 72 (9) mmHg. Prior to pregnancy, 22 (28%) women had been on insulin treatment. During pregnancy 74 women (93%) were treated with insulin and 11 (14%) with antihypertensive medication. Progression of diabetic retinopathy was observed in 11 (14%) women. Progression was mainly mild, but one woman with poor glycaemic control and uncontrolled hypertension progressed from mild retinopathy to sight-threatening retinopathy with proliferations, clinically significant macular oedema and impaired vision in both eyes. Progression of diabetic retinopathy was associated with a longer duration of diabetes (p = 0.03) and insulin treatment before pregnancy (p = 0.004).

CONCLUSIONS/INTERPRETATION

Despite a low risk of progression of retinopathy in pregnant women with type 2 diabetes, sight-threatening deterioration did occur.

Microalbuminuria, preeclampsia, and preterm delivery in pregnant women with type 1 diabetes: results from a nationwide Danish study

OBJECTIVE

To study the association between microalbuminuria and development of preeclampsia and preterm delivery in pregnant women with type 1 diabetes.

RESEARCH DESIGN AND METHODS

This was a population-based prospective study in 846 normoalbuminuric or microalbuminuric women with type 1 diabetes without antihypertensive treatment in early pregnancy. Data were collected prospectively by one to three caregivers in each center and reported to a central registry.

RESULTS

The prevalence of microalbuminuria in the first trimester was 10%, median diabetes duration was 11 years, and third-trimester A1C was 6.6%. The frequencies of preeclampsia and preterm delivery before 34 weeks in the microalbuminuric group were 40 and 13%, both significantly higher than those in the normoalbuminuric group (12 and 6%, respectively, P < 0.001). After adjustments for possible confounders, significant predictors for development of preeclampsia were microalbuminuria (odds ratio 4.0 [95% CI]), nulliparity (3.1 [1.9-5.1]), and third-trimester A1C (1.3 [1.1-1.5] per 1% increase). Delivery before 34 weeks was associated with early microalbuminuria in univariate analyses, but in multivariate analyses A1C was the only significant predictor of this outcome. Preeclampsia was associated with a threefold higher risk of delivery before 34 weeks.

CONCLUSIONS

The presence of microalbuminuria in early pregnancy is associated with a fourfold increased risk of developing preeclampsia. A1C values during pregnancy are highly predictive of both preeclampsia and preterm delivery. Future research with antihypertensive treatment in normotensive, microalbuminuric pregnant women to prevent preeclampsia is proposed.