HbA1c during pregnancy: Its relationship to meal related glycaemia and neonatal birth weight in patients with diabetes

Potentially modifiable predictors of adverse neonatal and maternal outcomes in pregnancies with gestational diabetes mellitus: can they help for future risk stratification and risk-adapted patient care?

BACKGROUND

Gestational diabetes mellitus (GDM) exposes mothers and their offspring to short and long-term complications. The objective of this study was to identify the importance of potentially modifiable predictors of adverse outcomes in pregnancies with GDM. We also aimed to assess the relationship between maternal predictors and pregnancy outcomes depending on HbA1c values and to provide a risk stratification for adverse pregnancy outcomes according to the prepregnancy BMI (Body mass index) and HbA1c at the 1st booking.

METHODS

This prospective study included 576 patients with GDM. Predictors were prepregnancy BMI, gestational weight gain (GWG), excessive weight gain, fasting, 1 and 2-h glucose values after the 75 g oral glucose challenge test (oGTT), HbA1c at the 1st GDM booking and at the end of pregnancy and maternal treatment requirement. Maternal and neonatal outcomes such as cesarean section, macrosomia, large and small for gestational age (LGA, SGA), neonatal hypoglycemia, prematurity, hospitalization in the neonatal unit and Apgar score at 5 min < 7 were evaluated. Univariate and multivariate regression analyses and probability analyses were performed.

RESULTS

One-hour glucose after oGTT and prepregnancy BMI were correlated with cesarean section. GWG and HbA1c at the end pregnancy were associated with macrosomia and LGA, while prepregnancy BMI was inversely associated with SGA. The requirement for maternal treatment was correlated with neonatal hypoglycemia, and HbA1c at the end of pregnancy with prematurity (all p < 0.05). The correlations between predictors and pregnancy complications were exclusively observed when HbA1c was ≥5.5% (37 mmol/mol). In women with prepregnancy BMI ≥ 25 kg/m2 and HbA1c ≥ 5.5% (37 mmol/mol) at the 1st booking, the risk for cesarean section and LGA was nearly doubled compared to women with BMI with < 25 kg/m2 and HbA1c <  5.5% (37 mmol/mol).

CONCLUSIONS

Prepregnancy BMI, GWG, maternal treatment requirement and HbA1c at the end of pregnancy can predict adverse pregnancy outcomes in women with GDM, particularly when HbA1c is ≥5.5% (37 mmol/mol). Stratification based on prepregnancy BMI and HbA1c at the 1st booking may allow for future risk-adapted care in these patients.

Association between glycated albumin, fructosamine, and HbA1c with neonatal outcomes in a prospective cohort of women with gestational diabetes mellitus

OBJECTIVE

To investigate whether glycated albumin, fructosamine, and hemoglobin A1c (HbA1c) are associated with neonatal complications in newborns of pregnant women with gestational diabetes mellitus (GDM).

METHODS

Between November 2016 and September 2017, women with a singleton pregnancy and GDM were enrolled in a prospective study in an obstetric Portuguese referral center. Glycemic markers were compared between mothers of newborns with and without complications. Multivariable logistic regression models and corresponding areas under the receiver operating characteristic curve (AUC) were used.

RESULTS

A total of 85 women participated in the study. Raised levels of glycated albumin and fructosamine were associated with at least one neonatal complication (OR- [odds ratio] estimate: 1.33, P=0.015; OR: 1.24, P=0.027, respectively) and with respiratory disorders at birth (OR 1.41, P=0.004; OR 1.26, P=0.014, respectively). HbA1c was not associated with these outcomes. All biomarkers were associated with large-for-gestational age (LGA) status (OR 1.61, P<0.001; OR 1.45, P<0.001; OR 3.62, P=0.032 for glycated albumin, fructosamine, and HbA1c, respectively). All had similar AUC for at least one neonatal complication (0.82; 0.81; 0.79, respectively). For newborn respiratory disorders, AUCs were 0.83, 0.81, and 0.76, respectively, and for LGA status were 0.81, 0.79, and 0.71, respectively.

CONCLUSION

Raised values of glycated albumin and fructosamine were associated with particular perinatal complications in newborns of mothers with GDM, better discriminating mothers of newborns with and without complications than HbA1c.

Association between glycated haemoglobin, glycated albumin and fructosamine with neonatal birthweight and large-for-date status infants in gestational diabetes mellitus: a prospective cohort study

This study aims to investigate associations between glycated haemoglobin (HbA1c), glycated albumin (GA) and fructosamine with neonatal birthweight in gestational diabetes mellitus (GDM). The prospective cohort consisted of 82 women with GDM and their newborns, enrolled between November 2016 and September 2017. Considering neonatal birthweight and birthweights ≥90th percentile for gestational age as outcomes, linear and logistic regression models were used, respectively. Fructosamine (R²=0.62) and GA (R²=0.61) performed very similarly between them and best than HbA1c (R²=0.58). The added value of GA or fructosamine to HbA1c resulted in increase in models' performances. GA attained the best discriminative ability regarding large-for-date status babies (AUC = 0.80, OR-estimate 1.58, p=.001) followed by fructosamine (AUC = 0.78, OR-estimate 1.42, p=.001) and HbA1c (AUC = 0.69, OR-estimate 3.09, p=.070). GA and fructosamine, besides from providing additional information to HbA1c, when used separately perform better than the traditional biomarker in predicting neonatal birthweight and large-for-date babies in pregnant women with GDM. Impact statement What is already known on this subject? HbA1c is the standard glycaemic indicator used in GDM. Its association with birthweight and large-for-date status has been previously reported. However, it has become increasingly questionable whether it is a suitable glycaemic marker in pregnancy. There is a growing interest in other non-traditional shorter-term glycaemic indicators, such as GA and fructosamine. Nevertheless, few studies exist and almost all are retrospective and with ethnically homogeneous study populations composed by pregnant women not only with GDM but also type 1 and type 2 diabetes mellitus. What do the results of this study add? Our prospective multi-ethnic cohort composed solely on pregnant women with GDM and their infants show that even though all of the aforementioned biomarkers are associated with birthweight and large-for-date status in GDM when used separately, GA and fructosamine seem to perform better than HbA1c. When used with HbA1c, they improve the predicting performance of the traditional marker. What are the implications of these findings for future clinical practice and/or further research? These findings suggest that GA and fructosamine can provide important additional or substitute information to HbA1c in GDM, namely in predicting birthweight and large-for-date status babies. Larger studies are needed to confirm if this non-traditional biomarkers can change clinical practice.

Safety of non-insulin glucose-lowering drugs in pregnant women with pre-gestational diabetes: A cohort study

AIMS

To evaluate the association between use of non-insulin antidiabetics in early pregnancy and the risk of miscarriages, stillbirths and major structural malformations.

MATERIALS AND METHODS

A cohort of 1511 pregnant women with pre-gestational diabetes linked to live births was identified using electronic medical records from The Health Improvement Network (THIN) for the period 1995 to 2012. Information on prescriptions, foetal outcomes and potential confounders was ascertained from both codes and free text in the THIN database. Odds ratios (OR) and 95% confidence intervals (CI) of adverse foetal outcomes in women treated with non-insulin antidiabetics during the first trimester compared to those on insulin were estimated using logistic regression to adjust for type of diabetes, glycaemic control and other maternal characteristics.

RESULTS

Among 311 pregnant women on non-insulin antidiabetics, 21.9% had a miscarriage and 1.6% a stillbirth; 1.9% of live births had major malformations. The corresponding frequencies for the 883 women on insulin were 13.3%, 1.7% and 9.6%. Insulin users more often had type 1 diabetes and poor glycaemic control. Compared to women with type 1 diabetes, those with type 2 diabetes had a higher risk of miscarriages (20.5% vs 12.8%) but a lower prevalence of malformations (4.0% vs 9.2%). Compared to women with HbA1c ≤7%, those with HbA1c >7% had a higher prevalence of malformations (12.6% vs 2.7%). After adjustment for diabetes type and glycaemic control, compared to insulin, non-insulin antidiabetic patients were associated with an OR for miscarriage of 1.19 (95% CI, 0.75-1.89), for stillbirths of 0.65 (95% CI, 0.16-2.58), and for major malformations of 0.25 (95% CI, 0.08-0.84).

CONCLUSION

Among women with diabetes, use of non-insulin antidiabetics early in pregnancy was not associated with greater risks of foetal losses or major malformations than was insulin.

Triplet Pregnancy in a Diabetic Mother With Kidney Transplant: Case Report and Review of the Literature

Triplet and higher-order multiple pregnancies can carry increased fetal and maternal complications. Reports of triplet pregnancies after kidney transplant are scarce and have been associated with perinatal complications. Presence of diabetes in such cases worsens both fetal and maternal outcomes. Here, we present a triplet pregnancy in a kidney transplant recipient with diabetes. We also reviewed the literature for causes, prevalence, and outcomes in association with chronic kidney disease, kidney transplant, and diabetes mellitus. The patient, a 31-year-female who received a living-donor kidney transplant, had a first-time pregnancy 6 years after transplant. Pregnancy was complicated by gestational diabetes, preeclampsia, and miscarriage. She continued to have postpartum-impaired glucose tolerance. She became pregnant again after 6 months but required insulin therapy during her third trimester. Pregnancy was terminated by cesarean section for a viable small boy. Two years later, she had triplet pregnancy after ovulation induction with clomiphene. Glycemic control was maintained using intensive insulin therapy guided by frequent home blood glucose monitoring (HbA1c was 5.8% at 22 wk). Both gynecologic care and nephrologic care were carried out through outpatient follow-up. Pregnancy was complicated by hypertension and mild renal dysfunction without proteinuria and ended in elective premature cesarean section at 32 weeks of gestation. She had 3 male babies with low birth weights (1320, 1380, 1275 g), with the largest baby developing sepsis and requiring an intensive care unit stay and then incubator for 49 days. The other 2 required incubators for 36 days. Their weights after 22 months were 9, 16, and 11 kg. The mother is now normotensive with normal renal function and impaired glucose tolerance. Care of diabetic kidney recipients with triplet pregnancy constitutes a special challenge requiring a multispecialty skilled team to ensure the best outcome.

Glycemic control and pregnancy outcomes in patients with diabetes in pregnancy: A retrospective study

CONTEXT

Diabetes in pregnancy (DIP) is either pregestational or gestational.

AIMS

To determine the relationship between glycemic control and pregnancy outcomes in a cohort of DIP patients.

SETTINGS AND DESIGN

In this 12-month retrospective study, a total of 325 Saudi women with DIP who attended the outpatient clinics at a tertiary center Riyadh, Saudi Arabia, were included.

SUBJECTS AND METHODS

The patients were divided into two groups, those with glycated hemoglobin (HbA1c) ≤6.5% (48 mmol/mol) and those with glycated hemoglobin (HbA1c) above 6.5%. The two groups were compared for differences in maternal and fetal outcomes.

STATISTICAL ANALYSIS USED

Independent Student's t-test and analysis of variance were performed for comparison of continuous variables and Chi-square test for frequencies. Odds ratio and 95% confidence intervals were calculated using logistic regression.

RESULTS

Patients with higher HbA1c were older (P = 0.0077), had significantly higher blood pressure, proteinuria (P < 0.0001), and were multiparous (P = 0.0269). They had significantly shorter gestational periods (P = 0.0002), more preterm labor (P < 0.0001), more perineal tears (P = 0.0406), more miscarriages (P < 0.0001), and more operative deliveries (P < 0.0001). Their babies were significantly of greater weight, had more Neonatal Intensive Care Unit (NICU) admissions, hypoglycemia, and macrosomia.

CONCLUSIONS

Poor glycemic control during pregnancy is associated with adverse maternal and fetal outcomes (shortened gestational period, greater risk of miscarriage, increased likelihood of operative delivery, hypoglycemia, macrosomia, and increased NICU admission). Especially at risk are those with preexisting diabetes, who would benefit from earlier diabetes consultation and tighter glycemic control before conception.

One-hour versus two-hour postprandial blood glucose measurement in women with gestational diabetes mellitus: which is more predictive?

The purpose of this study is to investigate postprandial 1-h (PP1) and 2-h (PP2) blood glucose measurements' correlation with adverse perinatal outcomes. This prospective cohort study consisted of 259 women with gestational diabetes mellitus. During each antenatal visit, HbA1c and fasting plasma glucose (FPG) as well as plasma glucose at PP1 and PP2 were analyzed. There were 144 patients on insulin therapy and 115 patients on diet therapy. A total of 531 blood glucose measurements were obtained at different gestational ages between 24 and 41 gestational weeks. PP2 plasma glucose measurements (but not PP1) were positively correlated with fetal macrosomia. But on adjusted analysis, neither PP1 nor PP2 measurements predicted perinatal complications. In addition to PP1 and PP2, neither FPG nor HbA1c were able to predict perinatal complications or fetal macrosomia when controlled for confounding factors except for a positive correlation between fetal macrosomia and HbA1c in patients on diet therapy. Postprandial 1-h and postprandial 2-h plasma glucose measurements were not superior to each other in predicting fetal macrosomia or perinatal complications. Based on our findings, it can be concluded that both methods may be suitable for follow-up as there are no clear advantages of one measurement over the other.

HbA1c: A Useful Screening Test for Gestational Diabetes Mellitus

BACKGROUND

Gestational diabetes mellitus (GDM) is associated with adverse maternal and fetal outcomes, and the oral glucose tolerance test (OGTT) is the recommended test for its diagnosis. We evaluated the role of glycated hemoglobin (HbA1c) in screening and diagnosis of GDM and its correlation with adverse pregnancy outcomes.

SUBJECTS AND METHODS

In this prospective observational study, OGTT and HbA1c were performed in 500 antenatal women between 24 and 28 weeks of gestation; the pregnant women were followed up thereafter. Repeat OGTT and HbA1c were done in women with GDM at 6 weeks postpartum.

RESULTS

Among the 500 women, 45 were diagnosed with GDM, for an incidence of 9%. The mean HbA1c level in women with GDM was 6.2 ± 0.6%, whereas it was 5.4 ± 0.5% in those with normoglycemia. Women with GDM had a higher incidence of pregnancy-related complications compared with normoglycemic women. An HbA1c cutoff of 5.3% had a sensitivity of 95.6% and a specificity of 51.6% for the diagnosis of GDM and would have avoided OGTT in approximately half of antenatal women, while missing 5% of the women. However, those with an abnormal HbA1c will require a confirmatory OGTT, as 50% of normoglycemic women would be misclassified as having GDM by this approach. On repeat testing postpartum, two of 45 women (4.4%) had overt diabetes mellitus, whereas five (11.1%) had impaired glucose tolerance.

CONCLUSIONS

Although HbA1c cannot replace OGTT in the diagnosis of GDM, it can be used as a screening test, avoiding OGTT in approximately 50% of women, if a cutoff of 5.3% is used.

1,5-Anhydroglucitol: a new predictor of neonatal birth weight in diabetic pregnancies

OBJECTIVE

To determine whether 1,5-anhydroglucitol is predictive of neonatal birth weight.

STUDY DESIGN

A retrospective cohort study including 85 pregnancies complicated by diabetes (Type 1=37, Type 2=24, gestational=24). Women had simultaneous hemoglobin A1c and 1,5-anhydroglucitol measurements every 4-8 weeks throughout pregnancy until delivery. Neonatal birth weight was evaluated by standardized z-scores. Linear regression analysis was performed to determine an association of 1,5-anhydroglucitol with neonatal birth weight z-score.

RESULTS

Type 1 diabetic patients had the lowest mean 1,5-anhydroglucitol of 3.5mcg/mL (SD=1.6mcg/mL) and highest mean hemoglobin A1c of 6.5% (SD=0.74%) compared to gestational diabetic patients who had the highest mean 1,5-anhydroglucitol of 6.7mcg/mL (SD=3.8mcg/mL) and lowest mean hemoglobin A1c of 6.0% (SD=0.94%). Mean 1,5-anhydroglucitol values were significantly different between diabetes types (p<0.01). Mean neonatal birth weight was above population averages for all diabetes classifications, although mean birth weight z-scores did not differ significantly between diabetic types (p=0.38). Multivariate linear regression showed a negative association between log-transformed 1,5-anhydroglucitol and birth weight (coefficient -0.82, 95% CI -1.19, -0.46).

CONCLUSION

In pregnancies complicated by diabetes, low 1,5-anhydroglucitol was associated with increased neonatal birth weight. 1,5-Anhydroglucitol may be useful in the assessment of glycemic control in pregnancy in addition to A1c.

Predictors of large and small for gestational age birthweight in offspring of women with gestational diabetes mellitus

AIM

To identify predictors of large and small for gestational age in women with gestational diabetes mellitus.

METHODS

A retrospective audit of clinical data analysed for singleton births in women diagnosed with gestational diabetes by Australasian Diabetes in Pregnancy Society guidelines from 1994 to 2009. Exclusions were: incomplete data, delivered at < 36 weeks gestation and/or last recorded weight > 4 weeks pre-delivery. We assessed: pre-pregnancy BMI, ethnicity, total maternal weight gain, weight gain before and after treatment initiation for gestational diabetes, HbA(1c) at gestational diabetes presentation and treatment modality (diet or insulin) and smoking. Birthweight was assessed using customized percentile charts (large for gestational age > 90th; small for gestational age < 10th percentile). Multiple regression analyses were undertaken; statistical significance was p < 0.05.

RESULTS

There were 1695 women first seen at (mean ± sd) 28.1 ± 5.3 weeks gestation (range 6-39). Ethnic mix was South-East Asian 36.7%, Middle Eastern 27.6%, European 22.4%, Indian/Pakistani 8.6%, Samoan 1.9%, African 1.5% and Maori 1.1%. Therapy was diet 69.1% and insulin 30.9%. Mean total weight gain was 12.3 ± 6.1 kg, the majority (10.6 ± 6.0 kg), gained before dietary intervention. There were 7.9% small for gestational age and 15.2% large for gestational age births. Significant independent large for gestational age predictors were: weight gain before intervention, pre-pregnancy BMI, weight gain after intervention and treatment type, but not HbA1c or smoking. Significant small for gestational age predictors were: weight gain before intervention, weight gain after intervention, but not pre-pregnancy BMI, HbA(1c) or smoking.

CONCLUSION

Conventional treatment for gestational diabetes mellitus concentrates on management of blood glucose levels. The trends identified here emphasize the need to also address pregnancy weight gain stratified by pre-pregnancy BMI.

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

Gestational diabetes mellitus (GDM) is a risk factor for delivering a large-for-gestational-age (LGA) infant. Haemoglobin A1c (A1C) is an indicator of glycaemic control. The objective of this study was to test whether higher A1C quartile at the time of diagnosis of GDM is associated with increased risk of delivering a LGA or macrosomic infant. Women with singleton pregnancies treated for GDM at a large diabetes and pregnancy programme located in Charlotte, North Carolina, were eligible for inclusion in this retrospective cohort study. Clinical information, including A1C at diagnosis, treatment, prior medical and obstetric history, and birth data were abstracted from medical records. LGA was defined as birthweight >90th percentile for gestational age and sex and macrosomia as birthweight >4000 g. Logistic regression was used to analyse the association of A1C at GDM diagnosis with risk of delivering LGA or macrosomic infants. This study included 502 women. Prevalences of LGA and macrosomia were 4% and 6% respectively. After adjustment there was no detectable trend of increased risk for LGA (P for trend = 0.12) or macrosomia (P for trend = 0.20) across increasing quartiles of A1C at GDM diagnosis. A1C at GDM diagnosis may not be linearly associated with LGA or macrosomia, possibly because of the mediating effect of strict glycaemic control in this clinical setting.

Diabetes gestacional: um algoritmo de tratamento multidisciplinar

O tratamento do diabetes gestacional é importante para evitar a morbimortalidade materno-fetal. O objetivo deste artigo é descrever o tratamento atualmente disponível para o manejo otimizado da hiperglicemia na gestação e sugerir um algoritmo de tratamento multidisciplinar. A terapia nutricional é a primeira opção de tratamento para as gestantes, e a prática de exercício físico leve a moderado deve ser estimulada na ausência de contraindicações obstétricas. O tratamento medicamentoso está recomendado quando os alvos glicêmicos não são atingidos ou na presença de crescimento fetal excessivo à ultrassonografia. O tratamento tradicional do diabetes gestacional é a insulinoterapia, embora mais recentemente a metformina venha sendo considerada uma opção segura e eficaz. A monitorização do tratamento é realizada com aferição da glicemia capilar e com avaliação da circunferência abdominal fetal por meio de ultrassonografia obstétrica a partir da 28ª semana de gestação.

Antepartum A1C, maternal diabetes outcomes, and selected offspring outcomes: an epidemiological review

Between 1989 and 2004, the prevalence of gestational diabetes mellitus (GDM) in the United States increased by 122%. Glycated haemoglobin, as measured by haemoglobin A1C (A1C), can potentially identify pregnant women at high risk for adverse outcomes associated with GDM including macrosomia and post-partum glucose intolerance. Our objective was to systematically review the literature with respect to A1C levels during pregnancy and associated maternal and offspring outcomes. We used MEDLINE to identify relevant publications from 1975 to 2009. We included articles if they met the following criteria: original full text articles in English; primary exposure of antepartum A1C; women with GDM at baseline or who developed GDM during the study; primary outcome of GDM, insulin use, post-partum abnormal glucose or type 2 diabetes (T2DM), birthweight, macrosomia or large for gestational age. Case series and case reports were excluded. Twenty studies met our criteria. A1C at GDM diagnosis was positively associated with post-partum abnormal glucose. Women with post-partum T2DM or impaired glucose tolerance had mean A1C at GDM diagnosis higher than those with normal post-partum glucose (P ≤ 0.002) and a 1% increase in A1C at GDM diagnosis was associated with 2.36 times higher odds of post-partum abnormal glucose 6 weeks after delivery [95% confidence interval 1.19, 4.68]. The association of A1C and birthweight varied substantially between studies, with correlation coefficients ranging from 0.11 to 0.51. A1C, a less burdensome and costly measure than an oral glucose tolerance test, appears to be an attractive measure for identifying women at high risk of adverse outcomes associated with GDM.