Severe hypoglycaemia during pregnancy in women with Type 1 diabetes is common and planning pregnancy does not decrease the risk

Smoking and diabetes interplay: A comprehensive review and joint statement

Evidence shows that smoking increases the risk of pre-diabetes and diabetes in the general population. Among persons with diabetes, smoking has been found to increase the risk of all-cause mortality and aggravate chronic diabetic complications and glycemic control. The current paper, which is a joint position statement by the French-Speaking Society on Tobacco (Société Francophone de Tabacologie) and the French-Speaking Society of Diabetes (Société Francophone du Diabète), summarizes the data available on the association between smoking and diabetes and on the impact of smoking and smoking cessation among individuals with type 1, type 2, and gestational diabetes mellitus. It also provides evidence-based information about the pharmacological and behavioral strategies for smoking cessation in these patients.

Mechanisms of Congenital Malformations in Pregnancies with Pre-existing Diabetes

PURPOSE OF REVIEW

Fetuses of diabetic mothers are at increased risk for congenital malformations. Research in recent decades using animal and embryonic stem cell models has revealed many embryonic developmental processes that are disturbed by maternal diabetes. The aim of this review is to give clinicians a better understanding of the reasons for rigorous glycemic control in early pregnancy, and to provide background to guide future research.

RECENT FINDINGS

Mouse models of diabetic pregnancy have revealed mechanisms for altered expression of tissue-specific genes that lead to malformations that are more common in diabetic pregnancies, such as neural tube defects (NTDs) and congenital heart defects (CHDs), and how altered gene expression causes apoptosis that leads to malformations. Embryos express the glucose transporter, GLUT2, which confers susceptibility to malformation, due to high rates of glucose uptake during maternal hyperglycemia and subsequent oxidative stress; however, the teleological function of GLUT2 for mammalian embryos may be to transport the amino sugar glucosamine (GlcN) from maternal circulation to be used as substrate for glycosylation reactions and to promote embryo cell growth. Malformations in diabetic pregnancy may be not only due to excess glucose uptake but also due to insufficient GlcN uptake. Avoiding maternal hyperglycemia during early pregnancy should prevent excess glucose uptake via GLUT2 into embryo cells, and also permit sufficient GLUT2-mediated GlcN uptake.

The effect of smoking on the risk of gestational diabetes mellitus and the OGTT profile during pregnancy

OBJECTIVE

To analyze the relationship between smoking and the risk of GDM, as well as with the OGTT profile during pregnancy.

PATIENTS AND METHODS

A total of 7437 pregnant women were studied. OGTT was performed at the 3rd trimester. Women were categorized as non-smokers (A), as those who ceased smoking at pregnancy (B), and as smokers (C).

RESULTS

5434 (73.1%) women were group A, 1191 (16%) group B and 812 (10.9%) group C. The rates of GDM among the groups were: A 33.7%, B 34.2%, C 34.2% (ns). However, the number of individuals requiring insulin treatment was significantly different: A 39.2%, B 47.5%, C 50.6% (p < 0.001). Regarding OGTT, fasting glucose levels were significantly higher in group C (89 ± 13 vs 86 ± 12 mg/dl) compared to A, whereas 3-h glucose values were significantly lower (104 ± 33 vs 112 ± 32 mg/dl) (p < 0.001). Group B demonstrated intermediate glucose concentrations. Similar findings were observed in women without GDM. In women with GDM, higher 1-h glucose levels were measured in group C (210 ± 31 vs 205 ± 28 mg/dl) compared with A (p = 0.024). Further, group C sub-analysis found that those who smoked more than 10 cigarettes showed significantly lower 3-h glucose levels (111 ± 31 vs 128 ± 40 mg/dl) compared to those who smoked less than 10 (p = 0.006). HbA1c in women with GDM was higher in group C (4.6 ± 0.6 vs 4.5 ± 0.6%) compared with A (p = 0.027).

CONCLUSIONS

The present study did not show any correlation between smoking and GDM risk. However, OGTT profile and HbA1c differed according to smoking status in women with and without GDM.

Prevalence of Hypoglycaemia among Insulin-Treated Pregnant Women with Diabetes Who Achieved Tight Glycaemic Control

Objectives

To determine the prevalence of hypoglycaemia using continuous glucose monitoring system (CGMS) among insulin-treated pregnant women with diabetes whose glycosylated haemoglobin (HbA1c) were <6.0% and identify the risk factors associated with hypoglycaemia occurrence.

Methodology

We conducted a cross-sectional study using 6-days CGMS to detect the prevalence of hypoglycaemia in 31 insulin-treated pregnant women with diabetes who achieved HbA1c <6.0%. Patients were required to log-keep their self-monitoring blood glucose (SMBG) readings and hypoglycaemia events.

Results

Eight women experienced confirmed hypoglycaemia with additional seven experienced relative hypoglycaemia, giving rise to prevalence rate of 45.2% (one had both confirmed and relative hypoglycaemia). Nine relative hypoglycaemia and 17 confirmed hypoglycaemic events were recorded. Sixteen (94%) out of 17 confirmed hypoglycaemia events recorded by CGMS were asymptomatic and were missed despite performing regular SMBG. Nocturnal hypoglycaemia events were recorded in seven women. Univariable analysis did not identify any association between conventional risk factors and hypoglycaemia events in our cohort.

Conclusion

Insulin-treated pregnant women with diabetes who achieved HbA1c <6.0% were associated with high prevalence of hypoglycaemia. Asymptomatic hypoglycaemia is common in our cohort and frequently missed despite regular SMBG. Present study did not identify any association between conventional risk factors and hypoglycaemia events in our cohort.

Smoking affects the oral glucose tolerance test profile and the relationship between glucose and HbA1c in gestational diabetes mellitus

AIMS

Current smokers in the general population have a lower 2 h plasma glucose after an oral glucose tolerance test (OGTT) and a higher HbA1c than non-smokers, but the relationships between OGTT/HbA1c and smoking status have not been addressed in pregnancy. We analysed glycaemic measurements in women with gestational diabetes mellitus in relation to smoking status.

METHODS

We performed a review of the prospectively collected database of the diabetes and pregnancy clinic. We included women with gestational diabetes mellitus and a singleton pregnancy who delivered between 1986 and 2006. Bivariate and multivariate analyses were used to evaluate patient characteristics in relation to smoking status.

RESULTS

A total of 2361 women met the inclusion criteria: 556 (23.5%) were active smokers, 266 (11.3%) quit during pregnancy and 1539 (65.2%) were non-smokers. Most baseline characteristics were similar across groups. Diagnostic OGTT was performed at a gestational age of [median (25th, 75(th) centiles)] 29 weeks (26, 33). Women who smoked at the beginning of pregnancy had a higher 1-h plasma glucose than non-smokers [11.8 (11, 12.7), 11.6 (11, 12.6) and 11.5 (10.8, 12.5) mmol/l, for active smokers, those who quit during pregnancy and non-smokers, respectively, P < 0.001] and a lower 3-h plasma glucose [7.3 (5.9, 8.4), 7.6 (6.4, 8.7) and 8.0 (6.8, 9.0) mmol/l, respectively, P < 0.001]. HbA1c was higher in women who smoked at the beginning of pregnancy. Multiple regression analysis confirmed the independent association of smoking status with HbA1c and OGTT plasma glucose.

CONCLUSIONS

In women with gestational diabetes mellitus who smoke at the beginning of pregnancy, the shape of the OGTT is consistent with accelerated glucose absorption, and HbA1c is higher than expected for glycaemic values.

Mechanisms of hypoglycemia unawareness and implications in diabetic patients

Hypoglycemia unawareness (HU) is defined at the onset of neuroglycopenia before the appearance of autonomic warning symptoms. It is a major limitation to achieving tight diabetes and reduced quality of life. HU occurs in approximately 40% of people with type 1 diabetes mellitus (T1DM) and with less frequency in T2DM. Though the aetiology of HU is multifactorial, possible mechanisms include chronic exposure to low blood glucose, antecedent hypoglycaemia, recurrent severe hypoglycaemia and the failure of counter-regulatory hormones. Clinically it manifests as the inability to recognise impeding hypoglycaemia by symptoms, but the mechanisms and mediators remain largely unknown. Prevention and management of HU is complex, and can only be achieved by a multifactorial intervention of clinical care and structured patient education by the diabetes team. Less know regarding the impact of medications on the development or recognition of this condition in patients with diabetes. Several medications are thought to worsen or promote HU, whereas others may have an attenuating effect on the problem. This article reviews recent advances in how the brain senses and responds to hypoglycaemia, novel mechanisms by which people with insulin-treated diabetes develop HU and impaired counter-regulatory responses. The consequences that HU has on the person with diabetes and their family are also described. Finally, it examines the evidence for prevention and treatment of HU, and summarizes the effects of medications that may influence it.

Glycemic targets in pregnancies affected by diabetes: historical perspective and future directions

The definition of optimal glycemic control in pregnancies affected by diabetes remains enigmatic. Diabetes phenotypes are heterogeneous. Moreover, fetal macrosomia insidiously occurs even with excellent glycemic control. Current blood glucose (BG) targets (FBG ≤95, 1-h post-prandial <140, 2 h <120 mg/dL) have improved perinatal outcomes, but arguably they have not normalized. The conventional management approach has been to replicate a pattern of glycemia in normal pregnancy. Although these patterns are lower than previously appreciated, a randomized controlled trial (RCT) has never compared current vs. lower glucose targets powered on maternal/fetal outcomes. This paper provides historical context to the current targets by reviewing evidence supporting their evolution. Using lower targets (FBG <90, 1 h <122, 2 h <110, mean BG ≤95 mg/dL) may help normalize outcomes, but phenotypic differences (type 1 vs. type 2 vs. gestational diabetes) might require different glycemic goals. There remains a critical need for well-designed RCTs to confirm optimal glycemic control that minimizes both small for and large for gestational age across pregnancies affected by diabetes.

Diabetes and pregnancy: an endocrine society clinical practice guideline

OBJECTIVE

Our objective was to formulate a clinical practice guideline for the management of the pregnant woman with diabetes.

PARTICIPANTS

The Task Force was composed of a chair, selected by the Clinical Guidelines Subcommittee of The Endocrine Society, 5 additional experts, a methodologist, and a medical writer.

EVIDENCE

This evidence-based guideline was developed using the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) system to describe both the strength of recommendations and the quality of evidence.

CONSENSUS PROCESS

One group meeting, several conference calls, and innumerable e-mail communications enabled consensus for all recommendations save one with a majority decision being employed for this single exception.

CONCLUSIONS

Using an evidence-based approach, this Diabetes and Pregnancy Clinical Practice Guideline addresses important clinical issues in the contemporary management of women with type 1 or type 2 diabetes preconceptionally, during pregnancy, and in the postpartum setting and in the diagnosis and management of women with gestational diabetes during and after pregnancy.

The incidence of severe hypoglycaemia in pregnant women with type 1 diabetes mellitus can be reduced with unchanged HbA1c levels and pregnancy outcomes in a routine care setting

AIMS

To investigate whether the incidence of severe hypoglycaemia in pregnant women with type 1 diabetes can be reduced without deteriorating HbA1c levels or pregnancy outcomes in a routine care setting.

METHODS

Two cohorts (2004-2006; n=108 and 2009-2011; n=104) were compared. In between the cohorts a focused intervention including education of caregivers and patients in preventing hypoglycaemia was implemented. Women were included at median 8 (range 5-13) weeks. Severe hypoglycaemia (requiring assistance from others) was prospectively reported in structured interviews.

RESULTS

In the first vs. second cohort, severe hypoglycaemia during pregnancy occurred in 45% vs. 23%, p=0.0006, corresponding to incidences of 2.5 vs. 1.6 events/patient-year, p=0.04. Unconsciousness and/or convulsions occurred at 24% vs. 8% of events. Glucagon and/or glucose injections were given at 15% vs. 5% of events. At inclusion HbA1c was comparable between the cohorts while in the second cohort fewer women reported impaired hypoglycaemia awareness (56% vs. 36%, p=0.0006), insulin dose in women on multiple daily injections was lower (0.77 IU/kg (0.4-1.7) vs. 0.65 (0.2-1.4), p=0.0006) and more women were on insulin analogues (rapid-acting 44% vs. 97%, p<0.0001; long-acting 6% vs. 76%, p<0.0001) and insulin pumps (5% vs. 23%, p<0.0001). Pregnancy outcomes were similar in the two cohorts.

CONCLUSIONS

A 36% reduction in the incidence of severe hypoglycaemia in pregnancy with unchanged HbA1c levels and pregnancy outcomes was observed after implementation of focused intervention against severe hypoglycaemia in a routine care setting. Improved insulin treatment, increased health professional education and fewer women with impaired hypoglycaemia awareness may contribute.

Comparison of Insulin Lispro Protamine Suspension with NPH Insulin in Pregnant Women with Type 2 and Gestational Diabetes Mellitus: Maternal and Perinatal Outcomes

Insulin therapy is still the gold standard in diabetic pregnancy. Insulin lispro protamine suspension is an available basal insulin analogue. Aim. To study pregnancy outcomes of women with type 2 and gestational diabetes mellitus when insulin lispro protamine suspension or human NPH insulin was added to medical nutrition therapy and/or short-acting insulin. Methods. In this retrospective study, for maternal outcome we recorded time and mode of delivery, hypertension, glycaemic control (fasting blood glucose and HbA1c), hypoglycemias, weight increase, and insulin need. For neonatal outcome birth weight and weight class, congenital malformations was recorded and main neonatal complications. Two-tail Student's t-test and chi-square test were performed when applicable; significant P < 0.05. Results. Eighty-nine pregnant women (25 with type 2 diabetes and 64 with gestational diabetes mellitus; 53 under insulin lispro protamine suspension and 36 under human NPH insulin) were recruited. Maternal and neonatal outcomes were quite similar between the two therapeutic approaches; however, insulin need was higher in NPH. At the end of pregnancy, eight women with gestational diabetes continued to use only basal insulin analogue. Conclusions. Pregnancy outcome in type 2 and gestational diabetes mellitus with insulin lispro protamine suspension was similar to that with NPH insulin, except for a lower insulin requirement.

Managing type 1 diabetes mellitus in pregnancy--from planning to breastfeeding

Type 1 diabetes mellitus in pregnant women increases the risk of adverse outcomes for mother and offspring. Careful preconception counselling and screening is important, with particular focus on glycaemic control, indications for antihypertensive therapy, screening for diabetic nephropathy, diabetic retinopathy and thyroid dysfunction, as well as review of other medications. Supplementation with folic acid should be initiated before conception in order to minimize the risk of fetal malformations. Obtaining and maintaining tight control of blood glucose and blood pressure before and during pregnancy is crucial for optimizing outcomes; however, the risk of severe hypoglycaemia during pregnancy is a major obstacle. Although pregnancy does not result in deterioration of kidney function in women with diabetic nephropathy and normal serum creatinine levels, pregnancy complications such as pre-eclampsia and preterm delivery are more frequent in these women than in women with T1DM and normal kidney function. Rapid-acting insulin analogues are considered safe to use in pregnancy and studies on long-acting insulin analogues have provided reassuring results. Immediately after delivery the insulin requirement declines to approximately 60% of the prepregnancy dose, and remains 10% lower than before pregnancy during breastfeeding.

The importance of hypoglycemia in diabetic patients

Hypoglycemia is one of the most important complications of diabetes treatment. The risk of severe hypoglycemia is higher in elderly patients, those having comorbidities such as vascular disease or renal failure, pregnant women and in children with type 1diabetes. Moreover, in type 2 diabetes, progressive insulin deficiency, longer duration of diabetes, and tight glycemic control increase the risk of hypoglycemia as much as type 1 diabetes.Episodes hypoglycemia may lead to impairment of counter-regulatory system, with the potential of development of hypoglycemia unawareness. So, hypoglycemia may increase the vascular events even death in addition to other possible detrimental effects. Glycemic control should be individualized based on patient characteristics with some degree of safety. Recognition of hypoglycemia risk factors, blood glucose monitoring, selection of appropriate regimens and educational programs for healthcare professionals and patients with diabetes are the major issues to maintain good glycemic control, minimize the risk of hypoglycemia, and prevent long- term complications.

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.