Does the availability of maternal HbA1c results improve the accuracy of sonographic diagnosis of macrosomia?

Biomarkers for Macrosomia Prediction in Pregnancies Affected by Diabetes

Large birthweight, or macrosomia, is one of the commonest complications for pregnancies affected by diabetes. As macrosomia is associated with an increased risk of a number of adverse outcomes for both the mother and offspring, accurate antenatal prediction of fetal macrosomia could be beneficial in guiding appropriate models of care and interventions that may avoid or reduce these associated risks. However, current prediction strategies which include physical examination and ultrasound assessment, are imprecise. Biomarkers are proving useful in various specialties and may offer a new avenue for improved prediction of macrosomia. Prime biomarker candidates in pregnancies with diabetes include maternal glycaemic markers (glucose, 1,5-anhydroglucitol, glycosylated hemoglobin) and hormones proposed implicated in placental nutrient transfer (adiponectin and insulin-like growth factor-1). There is some support for an association of these biomarkers with birthweight and/or macrosomia, although current evidence in this emerging field is still limited. Thus, although biomarkers hold promise, further investigation is needed to elucidate the potential clinical utility of biomarkers for macrosomia prediction for pregnancies affected by diabetes.

Cord blood C-peptide, insulin, HbA1c, and lipids levels in small- and large-for-gestational-age newborns

Background

Small- and large-for-gestational-age (SGA, LGA) newborns are associated with metabolic syndrome in their later life. Cord blood C-peptide, insulin, glycosylated hemoglobin (HbA1c), and lipids levels may be altered in SGA and LGA newborns; however, the results are conflicting. Therefore, this study aimed to determine the effect of cord blood markers on SGA and LGA newborns.

Material/Methods

This was a prospective cohort study and included 2873 term newborns of non-diabetic women. Among these newborns, 83 (2.9%) were SGA, 2236 (77.8%) were appropriate-for-gestational-age (AGA), and 554 (19.3%) were LGA newborns. Cord blood C-peptide, insulin, HbA1c, triglyceride (TG), total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), and low-density lipoprotein cholesterol (LDL-C) levels were measured. The chi-square, Kruskal-Wallis, and Mann-Whitney tests were used to analyze categorical variables and continuous variables, respectively. Multinomial logistic regression analysis was used to determine the independent effect of these variables on SGA and LGA newborns.

Results

Cord serum TG level was significantly higher in the SGA group than in AGA and LGA groups (p<0.05). The LGA group had significantly higher cord serum insulin level than AGA and SGA groups (p<0.05). After adjustment for confounding variables, including maternal age, parity, pre-pregnancy body mass index (BMI), education, annual household income, pregnancy-induced hypertension (PIH), mode of delivery, and newborn sex, high TG and insulin levels remained significantly associated with SGA and LGA newborns, respectively (p<0.05).

Conclusions

High cord serum TG and insulin levels are independently associated with SGA and LGA newborns, respectively.

Effect of maternal lipid profile, C-peptide, insulin, and HBA1c levels during late pregnancy on large-for-gestational age newborns

BACKGROUND

Large-for-gestational age (LGA) newborns can increase the risk of metabolic syndrome. Previous studies have shown that the levels of maternal blood lipids, connecting peptide (C-peptide), insulin and glycosylated hemoglobin (HbA1c) were significantly different between LGA and appropriate-for-gestational age (AGA) newborns. This study aimed to determine the effect of the levels of maternal lipids, C-peptide, insulin, and HbA1c during late pregnancy on LGA newborns.

METHODS

This study comprised 2790 non-diabetic women in late pregnancy. Among their newborns, 2236 (80.1%) newborns were AGA, and 554 (19.9%) newborns were LGA. Maternal and neonatal characteristics were obtained from questionnaires and their case records. The levels of maternal fasting serum apolipoprotein A1 (ApoA1), triglyceride (TG), total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), C-peptide, insulin and blood HbA1c were measured. The chi-square and Mann-Whitney U test were used to analyze categorical variables and continuous variables between the AGA and LGA groups, respectively. Binary logistic regression analysis was made to determine the independent risk factors for LGA newborns.

RESULTS

Maternal TG, C-peptide, insulin and HbA1c levels were significantly higher in the LGA group than in the AGA group (P<0.05). The LGA group had significantly lower levels of maternal TC, HDL-C and LDL-C than the AGA group (P<0.05). After adjustment for confounding variables, including maternal age, pre-pregnancy body mass index, education, smoking, annual household income, amniotic fluid volume, gestational hypertension, newborn gender and gestational age at blood collection, high maternal TG levels remained significantly associated with LGA newborns (P<0.05).

CONCLUSION

High maternal TG level during late pregnancy is significantly associated with LGA newborns.

Biomarkers of maternal diabetes and its complication in pregnancy

There are specific biomarkers - indicators of normal and abnormal processes - in diabetic pregnancies that predict the degree of diabetic control as well as embryonic and fetal growth and development. They can be detected in maternal blood, amniotic fluid or in the cord plasma of the newborn infant. While the cord plasma levels are of little clinical relevance because they do not allow us to interfere with the outcome of pregnancy, biomarkers in maternal blood or amniotic fluid may help us to better control the outcome of diabetic pregnancies. Important biomarkers in maternal blood are fasting glucose, HbA1c and IGFs. Relevant biomarkers in amniotic fluid are insulin, erythropoietin and markers of bone formation and resorption. Cord plasma biomarkers include IGFs, leptin, adiponectin, resistin, markers of oxidative stress and of hypoxia. Whether these biomarkers can be predictors of long term outcome in infants of diabetic mothers is yet to be determined.

Management of gestational diabetes mellitus

The incidence of gestational diabetes mellitus (GDM) is on the increase and, if not diagnosed, managed and treated adequately, can have unfavorable maternal and fetal outcomes. Several studies have shown that glycemic values considered as adequate in the past when monitoring GDM failed to contain these adverse outcomes and randomized trials are needed to ascertain whether these targets should be lowered. Dietary restrictions remain the mainstay of GDM management and suitable physical exercise can help too. The use of rapid-acting insulin analogues (lispro and aspart) are novel treatments for improving metabolic control by reducing postprandial glycemia, while long-acting insulin analogues need to be evaluated by further studies for safety in clinical use before they can be prescribed. Numerous studies have found glyburide and metformin safe in women with GDM but more randomized controlled trials are needed, with a long-term follow-up of mother and child, to confirm these results.

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.