Antenatal haemoglobin A1c and risk of large-for-gestational-age infants in a multi-ethnic cohort of women with gestational diabetes

Association between HbA1c Levels and Fetal Macrosomia and Large for Gestational Age Babies in Women with Gestational Diabetes Mellitus: A Systematic Review and Meta-Analysis of 17,711 Women

Gestational diabetes mellitus (GDM) is the most common metabolic disorder in pregnancy. GDM is associated with serious maternal and fetal complications, in particular, fetal macrosomia and large for gestational age (LGA), which predisposes to a higher risk of childhood obesity and type 2 diabetes mellitus later in life. Early prediction and diagnosis of GDM leads to early interventions such as diet and lifestyle, which could mitigate the maternal and fetal complications associated with GDM. Glycated haemoglobin A1c (HbA1c) has been widely used for monitoring, screening for and diagnosing diabetes and prediabetes. Increasing evidence has also showed that HbA1c could indicate fetal glucose supply. Thus, we hypothesise that the HbA1c level at around 24 to 28 weeks may predict the development of fetal macrosomia or an LGA baby in women with GDM, which could be useful for better prevention of fetal macrosomia and LGA. We searched MEDLINE, EMBASE, Cochrane and Google Scholar databases from inception to November 2022 for relevant studies that reported at least one HbA1c level during 24-28 weeks of pregnancy and fetal macrosomia or an LGA baby. We excluded studies that were not published in the English language. No other search filters were applied during the search. Two independent reviewers selected eligible studies for meta-analysis. Two independent reviewers performed data collection and analyses. The PROSPERO registration number is CRD42018086175. A total of 23 studies were included in this systematic review. Of these, 8 papers reported data of 17,711 women with GDM that allowed for inclusion in a meta-analysis. The obtained results demonstrated the prevalence of fetal macrosomia was 7.4% and of LGA, 13.36%. Meta-analyses showed that the estimated pooled risk ratio (RR) for LGA in women with high HbA1c values compared to normal or low values was 1.70 (95% CI: 1.23-2.35), p = 0.001; and the pooled RR for fetal macrosomia was 1.45 (95% CI: 0.80 to 2.63), p = 0.215. Further research is needed to evaluate the utility of HbA1c levels in predicting the delivery of a baby with fetal macrosomia or LGA in pregnant women.

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.

A critical appraisal and potentially new conceptual approach to screening and diagnosis of gestational diabetes

The aim of this article was a critical appraisal of current GDM screening and diagnosis status as well as a presentation of a potentially new approach to this perinatologic and public health problem of increasing clinical significance. Medline, EMBASE and Cochrane databases were searched. Most professional organisations recommend universal screening at 24-28 weeks of gestation, while some of them state that selective screening could also be recommended. Expert opinions regarding GDM diagnosis significantly differ throughout the world. Authors call for an open and broad professional and scientific discussion and suggest a combination of screening and diagnosis procedures in a form of one-step 1-h screening method, creation of regional GDM diagnostic criteria and standardisation of outcome-based randomised control trials. They also advise introduction of a conceptually new approach, where the risk of hyperglycaemia rather than insisting on GDM diagnosis itself should be detected.

Measuring glycated haemoglobin in women with gestational diabetes mellitus: How useful is it?

BACKGROUND

Glycated haemoglobin (HbA1c) is an important tool for assessing glycaemic status in patients with diabetes, but its usefulness in gestational diabetes mellitus (GDM), is unclear.

AIMS

The aim of this study is to evaluate whether HbA1c in women with GDM is valuable in predicting adverse pregnancy outcomes.

MATERIALS AND METHODS

A retrospective review of women with GDM who had HbA1c measured at diagnosis of GDM (GHb-diag) and at 36 weeks gestation (GHb-36 weeks) was conducted. The association between HbA1c and various pregnancy outcomes was assessed RESULTS: Among 1244 women with GDM in our cohort, both GHb-diag and GHb-36 weeks were independent predictors for large-for-gestation (LGA) babies (OR 1.06, P = 0.005 and OR 1.06, P = 0.002, respectively) and neonatal hypoglycaemia (OR 1.10, P < 0.001 and OR 1.09, P < 0.001, respectively). Women with HbA1c ≥ 5.4% (35 mmol/mol) at diagnosis had significantly greater risk for LGA (15.3% vs 8.2%, P < 0.001) and neonatal hypoglycaemia (42.2% vs 23.6%, P < 0.001) than those below this cut-off. The difference between GHb-diag and GHb-36 weeks was small and improvement in HbA1c by 36 weeks was not associated with better pregnancy outcomes.

CONCLUSION

We showed that measurement of HbA1c, either at the time of diagnosis of GDM or toward the end of pregnancy, were both associated with adverse pregnancy outcomes. Women with elevated HbA1c (>5.4% or 35 mmol/mol) at diagnosis of GDM should be monitored closely during pregnancy. However, there is not enough evidence to suggest that repeating HbA1c toward the end of pregnancy will provide additional information in predicting adverse pregnancy outcomes.

The utility of HbA1c for screening gestational diabetes mellitus and its relationship with adverse pregnancy outcomes

AIMS

To evaluate the utility of glycated hemoglobin A1c (HbA1c) for screening gestational diabetes mellitus (GDM) and analyze its association with adverse pregnancy outcomes in a cohort of pregnant women.

METHODS

Women with singleton pregnancies, who completed a 2h oral glucose tolerance test (OGTT) and HbA1c test at gestational week 24-28 were enrolled in this retrospective study. Clinical information was obtained and statistical analyses were performed to assess the diagnostic value of HbA1c for GDM and the association of HbA1c with adverse pregnancy outcomes.

RESULTS

Of the 1959 pregnant women enrolled in the study, 413 were diagnosed with GDM. A HbA1c cutoff value <4.8% (29mmol/mol) showed adequate sensitivity to exclude GDM (85.0%) but low specificity (31.8%). While HbA1c cutoff value ≥5.5% (37mmol/mol) presented adequate specificity (95.7%) but low sensitivity (14.8%) in diagnosing GDM. Adoption of HbA1c as a screening test for GDM could eliminate the need for an OGTT in 34.7% women in our study, however, with 6.5% being wrongly diagnosed. HbA1c level was significantly associated with the risk of preterm delivery, neonatal hyperbilirubinemia, and neonatal asphyxia.

CONCLUSIONS

Whether adoption of HbA1c as a screening test for GDM would benefit pregnant women remains to be determined. However, HbA1c might be a useful tool to predict patients at increased risk of several adverse pregnancy outcomes.

Is There a Role for HbA1c in Pregnancy?

Outside pregnancy, HbA1c analysis is used for monitoring, screening for and diagnosing diabetes and prediabetes. During pregnancy, the role for HbA1c analysis is not yet established. Physiological changes lower HbA1c levels, and pregnancy-specific reference ranges may need to be recognised. Other factors that influence HbA1c are also important to consider, particularly since emerging data suggest that, in early pregnancy, HbA1c elevations close to the reference range may both identify women with underlying hyperglycaemia and be associated with adverse pregnancy outcomes. In later pregnancy, HbA1c analysis is less useful than an oral glucose tolerance test (OGTT) at detecting gestational diabetes. Postpartum, HbA1c analysis detects fewer women with abnormal glucose tolerance than an OGTT, but the ease of testing may improve follow-up rates and combining HbA1c analysis with fasting plasma glucose or waist circumference may improve detection rates. This article discusses the relevance of HbA1c testing at different stages of pregnancy.

The associations between triglyceride to high-density lipoprotein cholesterol ratios and the risks of gestational diabetes mellitus and large-for-gestational-age infant

OBJECTIVE

To evaluate the associations between triglyceride to high-density lipoprotein cholesterol (TG/HDL-C) ratios and the risks of gestational diabetes mellitus (GDM) and delivering large-for-gestational-age (LGA) infant.

DESIGN

This was a single-centre prospective observational study.

PATIENTS

Six hundred and thirty-six women with a singleton pregnancy were recruited.

MEASUREMENTS

Lipids profile, HbA1c and glucose were measured at the time of oral glucose tolerance test (OGTT) during 24-28 gestational weeks. TG/HDL-C ratios were calculated and clinical data including perinatal parameters were analysed.

RESULTS

The prevalence of GDM was 17·30% (n = 110) and LGA was 3·93% (n = 25) in this study. TG/HDL-C ratios were found to be significantly higher in GDM group (P < 0·01) and LGA group (P = 0·045) compared with those in non-GDM group and non-LGA group, respectively. TG/HDL-C ratios were independently associated with the risks of GDM (OR = 1·64, P = 0·02) and LGA (OR = 2·87, P < 0·01). The area under the combined ROC curve of TG/HDL-C ratio and HbA1c to detect GDM was 0·705 (95% CI, 0·637-0·772). Furthermore, the area under the ROC curve of TG/HDL-C ratio combined with HbA1c and prepregnancy BMI to detect LGA was 0·806 (95% CI, 0·719-0·893).

CONCLUSIONS

TG/HDL-C ratios in combination with HbA1c and prepregnancy BMI can be good markers to predict the risks of GDM and delivering LGA infant.

Feasibility of neonatal pulse wave velocity and association with maternal hemoglobin A1c

BACKGROUND

Use of non-invasive peripheral arterial tonometry to assess arterial stiffness has not been studied in neonates. Perinatal factors impact childhood vascular health, but the effect in neonates remains to be examined.

OBJECTIVES

To examine the feasibility of pulse wave velocity (PWV) among healthy term neonates, and to evaluate the effects of perinatal factors on neonatal PWV.

METHODS

Pregnant women with singleton gestation presenting for routine care were enrolled. Postnatally, PWV measurements of their neonates were obtained using an arterial tonometer. A variability index was calculated for each PWV measurement. Intra- and inter-observer reproducibility were illustrated with Bland-Altman plots. Medical records were reviewed. Relationships between neonatal PWV and perinatal factors were examined.

RESULTS

PWV measurements were attempted in 76 neonates and successfully obtained in 67 (88%). Using PWV measurements with a variability index ≤ 0.25 (48 neonates), the intra-class coefficient was 0.69. The mean differences (limits of agreement) for intra- and inter-rater reproducibility were 0.02 (-3.64 to 3.60) and 0.34 (-2.23 to 2.39), respectively. Median neonatal PWV was 2.80 m/s (range 0.60-8.40). Neonates of mothers with HgbA1c ≥6% had significantly higher PWV than neonates of mothers with HgbA1c <6% (4.12 m/s, 95% CI 3.22-5.02, vs. 2.78 m/s, 95% CI 2.28-3.28, p = 0.02).

CONCLUSIONS

Neonatal PWV using peripheral arterial tonometry is feasible and reproducible when using measurements with a variability index ≤ 0.25. Neonates of mothers with increased HgbA1c had higher PWV, suggesting an effect of maternal hyperglycemia on neonatal vasculature. The long-term implications of this finding warrant further investigation.

Application of glycated hemoglobin in the perinatal period

Glycated hemoglobin (HbA1c) is a special fragment formed by the binding of glucose to the C chain or D chain of hemoglobin A and as a result of non-enzymatic catalysis of mature hemoglobin and glucose, which is an indicator used to evaluate the blood glucose control in diabetes mellitus (DM) patients. Recent researches indicated that HbA1c could be applied in gestational diabetes mellitus (GDM) and pregnancy combined DM, and increasing of HbA1c was close associated with adverse outcomes of women with pregnancy combined DM and GDM. HbA1c was reported to have a significant importance in monitoring congenital malformation, abortion, perinatal mortality, preeclampsia, postpartum abnormal glucose metabolism, vascular complications and so on, which could be a test item during the second trimester. Sensitivity of HbA1c in diagnoses of DM is lower than oral glucose tolerance test (OGTT), thus OGTT is still the golden standard of GDM. Emphasis should be put on standardization of detection and threshold of HbA1c and establishment of HbA1c normal ranges of different trimesters, when HbA1c is used to diagnose pregnancy combined DM and GDM, and evaluate effects of treatments.

Is gestational diabetes mellitus an independent risk factor for macrosomia: a meta-analysis?

PURPOSE

The aim of our meta-analysis was to explore whether gestational diabetes mellitus (GDM) is an independent risk factor for macrosomia or not.

METHODS

Three databases were systematically reviewed and reference lists of relevant articles were checked. Meta-analysis of published epidemiological studies (cohort and case-control studies) comparing whether GDM was associated with macrosomia. Calculations of pooled estimates were conducted in random-effect models. Heterogeneity was tested by using Chi square test and I (2) statistics. Publication bias was estimated from Egger's test (linear regression method) and Begg's test (rank correlation method).

RESULTS

Twelve studies met the inclusion criteria, including five cohort studies and seven case-control studies. The meta-analysis showed that GDM was associated with macrosomia independent of other risk factors. The adjusted odds ratio was 1.71, 95% CI (1.52, 1.94) in random-effect model, stratified analyses showed no differences regarding different study design, quality grade, definition of macrosomia, location of study and number of confounding factors adjusted for. There was no indication of a publication bias either from the result of Egger's test or Begg's test.

CONCLUSION

Our findings indicate that GDM should be considered as an independent risk factor for newborn macrosomia. To adequately evaluate the clinical evolution of GDM need to be carefully assessed and monitored.