The postprandial glucose profile in the diabetic pregnancy

Use of new technologies for monitoring and treating diabetes in pregnancy

During the last century, there were two breakthroughs in diabetes management and monitoring that changed the course of treatment: the discovery of insulin and the progress in the understanding of glucose monitoring. As technology evolved, glucose monitoring and insulin administration can now be achieved in a continuous fashion. In this review, the authors focus on the utility of new technologies in the management and monitoring of diabetes in pregnancy.

Glyburide for the treatment of gestational diabetes. A critical appraisal

The clinical experience with glyburide treatment of GDM has moved ahead of the science. A single randomized controlled trial of glyburide versus insulin indicates that glyburide treatment can provide a relatively safe alternative to insulin therapy. Subsequent retrospective trials have shown that up to 20% of GDM patients, especially those with substantial pretreatment hyperglycemia, are likely to require adjunctive or alternative therapy with insulin. These follow-on trials have also demonstrated that glyburide treatment, compared with insulin, actually results in lower mean glucose values and a higher percentage of "excellent glycemic control" with fewer hypoglycemic episodes. With the emerging view that glyburide treatment compared with insulin improves glycemic profiles, it should be expected to reduce the frequency of newborn obesity. Larger randomized controlled trials are necessary to clarify this question and the concerns regarding neonatal metabolic morbidity in glyburide-treated offspring.

The role of continuous glucose monitoring in clinical decision-making in diabetes in pregnancy

BACKGROUND

The continuous glucose monitoring system (CGMS) is a novel tool to assess 24-h glucose fluctuations. In pregnancies complicated by diabetes, where excellent glucose control is desired to improve maternal and fetal outcomes, CGMS may have a role in fine-tuning management.

AIMS

To assess the usefulness of CGMS in pregnant women with diabetes for medical decision-making and to evaluate patient tolerability and perception of usefulness.

METHODS

Pregnant women with diabetes at the Werribee Mercy Hospital were offered CGMS in the setting of their standard diabetes care. Treating clinicians were asked if the CGMS altered management decisions from those based on conventional glucose monitoring. The accuracy of the CGMS was assessed by comparison with the patients' finger-prick glucose readings. Patients completed a feedback questionnaire after having the CGMS and viewing their results.

RESULTS

CGMS traces (n = 68) were obtained in 55 pregnant women - 37 with gestational diabetes, ten with type 2 and eight with type 1 diabetes. Forty-two of 68 (62%) traces were assessed as providing additional information which altered clinical management decisions. This included showing undetected postprandial hyperglycaemia and overnight hypoglycaemia. Subject feedback was generally positive, with 37 of 48 (77%) respondents reporting that the benefits of the CGMS outweighed the inconvenience.

CONCLUSION

CGMS is a well-tolerated clinically useful tool in the management of gestational diabetes and pre-existing diabetes in pregnancy.

Intensive insulin therapy in pregnancy: strategies for successful implementation in pregestational diabetes mellitus

The role of intensive insulin therapy (IIT) in the reduction of long-term diabetes-related complications is well established. Normal blood glucose level prior to and during pregnancy is critical in reducing both short- and long-term morbidity and mortality in mother and infant. IIT in pregnancy, though occasionally challenging, is necessary to achieve and maintain normal blood glucose level during pregnancy. Current knowledge and recent advances in insulin formulations and delivery systems have improved our ability to achieve glycemic targets in pregnancy while limiting maternal and fetal morbidity. The objective of this review is to discuss contemporary strategies for successful use of IIT in pregnancy.

Acute hyperglycemia in uterine arteries from pregnant, but not non-pregnant mice, enhances endothelium-dependent relaxation

Poorly controlled diabetes in pregnancy, characterized by hypo- and hyperglycemia, is associated with adverse outcomes. We hypothesized that aberrant glucose levels affect vascular function in pregnancy. The effects of glucose concentration on constriction and endothelium-dependent relaxation in uterine arteries of normal C57BL/6 mice were examined. Ex-vivo arteries from 18 pregnant and 14 non-pregnant mice were mounted on a wire myograph, constricted with phenylephrine and relaxed with incremental doses of acetylcholine, in physiological saline solution containing 5 mmol/L glucose. Arteries were then exposed to solutions with 2, 5, 8 or 12 mmol/L glucose for 30 min and constriction/relaxation repeated. On altering glucose concentrations to 2, 8 or 12 mmol/L, maximal constriction was increased in arteries from pregnant but not from non-pregnant mice (paired t-test, p<0.05). Endothelium-dependent relaxation was enhanced at 12 mmol/L glucose in arteries from pregnant (two-way ANOVA, p<0.01), but not from non-pregnant mice. Endothelium-dependent relaxation in the uterine artery was pre-dominantly mediated by a non-nitric oxide/non-prostanoid mechanism, with a smaller contribution from nitric oxide, and no prostanoid-mediated relaxation. In summary, acute changes in glucose concentration alter both constriction and endothelium-dependent relaxation in uterine arteries of normal pregnant mice; these effects are unique to pregnancy.

Glucagon secretion and autonomic signaling during hypoglycemia in late pregnancy

We examined net pancreatic norepinephrine (NE) spillover, pancreatic polypeptide (PP) release, and the decrement in C-peptide to identify factors involved in the blunted counterregulatory glucagon response in pregnancy. Conscious pregnant [pregnant hypoglycemic (Ph); 3rd trimester; n = 8] and nonpregnant [nonpregnant hypoglycemic (NPh); n = 6] dogs were studied during insulin-induced (approximately 12-fold basal insulin concentrations) hypoglycemia (plasma glucose 3.1 mM). Additional dogs were studied during hyperinsulinemic euglycemia [nonpregnant euglycemic (NPe), n = 4; pregnant euglycemic (Pe), n = 5; plasma glucose 6 mM]. Arterial glucagon concentrations declined similarly in NPe and Pe. Areas under the curve (AUCs) of the changes in glucagon and epinephrine were seven- and threefold greater in NPh than Ph (P < 0.05 between groups for both). Glucagon secretion fell below basal in NPe, Pe, and Ph but rose significantly in NPh. C-peptide declined 0.25 +/- 0.06, 0.12 +/- 0.11, 0.28 +/- 0.05, and 0.13 +/- 0.02 ng/ml in NPe, Pe, NPh, and Ph, respectively (P < 0.05, NPh vs. Ph). AUCs of NE spillover were 516 +/- 274, 265 +/- 303, 506 +/- 94, and -63 +/- 79 ng, respectively (P < 0.05, NPh vs. Ph). The AUC of PP release was approximately threefold greater in NPh than Ph (P < 0.05) but not different between euglycemic groups. The current evidence strongly suggests that the blunting of glucagon secretion during insulin-induced hypoglycemia in pregnancy is related to generalized impairment of a number of different signals, including parasympathetic and sympathoadrenal stimuli and altered sensing of circulating and/or intraislet insulin.

[Use of continuous subcutaneous insulin infusion by a portable insulin pump during pregnancy in women with type 1 diabetes mellitus]

BACKGROUND/AIM

Diabetes mellitus is associated with an increased risk for neonatal morbidity and mortality. One of the most important goals in treating pregnancies complicated with diabetes is keeping glucose level within the normal range, especially in the first trimester. A portable insulin pump for continuous subcutaneous insulin infusion (CSII) represents the best form of therapy for patients with type 1 diabetes mellitus during pregnancy. The aim of our study was to evaluate the effects of therapy with a portable insulin pump for continuous subcutaneous insulin infusion during the first trimester of pregnancy on the quality of glycoregulation and pregnancy outcome in women with type 1 diabetes mellitus.

METHODS

A total of 17 newly diagnosed pregnant women with type 1 diabetes mellitus were treated with CSII therapy for three months. The parameters of glycoregulation (hemoglobin A, glycosylated--HbAlc, mean blood glucose value in daily profiles--MBG, daily requirement for insulin--IJ/kg BM), lipid levels, blood preassure and renal function were estimated before and after the therapy. These parameters were correlated with parameters of pregnancy outcome: fetal weight, APGAR score, duration of pregnancy.

RESULTS

There was a significant improvement in HbA1c (8.94 +/- 1.62 vs. 6.90 +/- 1.22 %,p < 0.05), MBG (9.23 +/- 2.22 vs. 6.41 +/- 1.72 mmol/l, p < 0.01), and daily requirement for insulin (0.66 +/- 0.22 vs. 0.55 +/- 0.13 IJ/kg BM, p < 0.05) during the CSII therapy. There were significant correlations between fetal weight and HbAlc (r = -0.60, p < 0.05), triglyceride levels (r = -0.63, p < 0.01), and the number of pregnancies (r = -0.62, p < 0.01), as well as between APGAR score and MBG (r = -0.52, p < 0.05) and cholesterol levels (r = -0.65, p < 0,01) before a portable insulin pump was applicated.

CONCLUSIONS

There was a significant improvement in the quality of glycoregulation during CSII therapy in the pregnant women with type 1 diabetes mellitus. The quality of glycoregulation in the moment of conception was the important factor for pregnancy outcome.