Abnormal fasting, post-load or combined glucose values on oral glucose tolerance test and pregnancy outcomes in women with gestational diabetes mellitus

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Abstract

Aims

This study aimed to investigate whether pregnancies complicated by gestational diabetes mellitus (GDM) present differences in the outcomes according to the findings on oral glucose tolerance test (OGTT), including fasting, post-load or combined abnormal blood glucose.

Materials

This was a prospective cohort study including 831 singleton pregnancies with GDM per the IADPSG criteria. According to their fasting blood glucose value on OGTT the women were categorized in three groups: (i) GDM women with fasting plasma glucose levels > 92 mg/dl and normal post-load values (T0 abnormal group), (ii) patients with abnormal values at 60′ and/or 120′ and normal fasting values (T-post group) and (iii) patients with combined fasting and post-load abnormal blood glucose values (T-comb). Regression analysis was used to test the independent contribution of the different groups, along with maternal and fetal characteristics, in prediction of (i) large for gestational age (LGA), (ii) need for insulin treatment and (iii) birthweight centile.

Results

GDM with abnormal fasting blood glucose was an independent risk factor for LGA (OR 2.91, 95% CI 1.33–6.36) and was associated with higher birthweight centile (10.25, 95% CI 0.27–20.25). GDM with combined fasting and post-load abnormal blood glucose was an independent risk factor for insulin treatment (OR 2.94, 95% CI 1.93–4.47).

Conclusions

Women with GDM and abnormal fasting blood glucose are at increased risk for large for gestational age neonates, while women with GDM and combined fasting and post-load abnormal blood glucose are at increased risk for insulin therapy.

Introduction

Gestational diabetes mellitus (GDM) develops during pregnancy in women whose pancreatic function is insufficient to overcome the insulin resistance associated with the pregnant state [1]. According to the International Association of Diabetes and Pregnancy Study Groups (IADPSG) criteria, the diagnosis of GDM is established when elevated plasma glucose is detected during a 75 g 2-hour oral glucose tolerance test (OGTT) between the 24th and 28th weeks of gestation [2]. According to the Hyperglycemia and Adverse Pregnancy Outcome (HAPO) Study, approximately half of women diagnosed with GDM had abnormal fasting blood glucose, while the rest had abnormal post-prandial blood glucose values [3]. Previous studies have reported that abnormal fasting blood glucose is associated with increased need for insulin therapy in GDM complicated pregnancies [4], [5], [6], [7]. Aim of this study is to investigate, the differences between GDM complicated pregnancies with abnormal fasting, post-load or combined blood glucose values on OGTT, regarding outcomes of the pregnancy.

Section snippets

Study design

We followed prospectively a cohort of pregnant women with singleton pregnancy and gestational diabetes mellitus (GDM), who attended our prenatal clinic.

Setting

Our study is a part of a large prospective study from 2010 to 2018, undertaken in the Second Department of obstetrics and Gynaecology, National and Kapodistrian University of Athens, Areteion Hospital in collaboration with a private medical setting of antenatal care Embryocare, Fetal Medicine Unit, Athens, Greece. All participating women signed

Results

From the initial cohort of 10.638 pregnancies, 6818 met the inclusion criteria, of which 831 (11.5%) were complicated by GDM. 180 (21.7%) of the GDM complicated pregnancies had abnormal fasting only blood glucose at OGTT, 402 (48.4%) had abnormal post-load only blood glucose and 249 (30%) had combined fasting and post-load abnormal blood glucose values. Figure 1 displays the selection process of the included cohort.

Main findings

We compared pregnancy outcomes of women with GDM and abnormal fasting blood glucose at OGTT (T0) to those with abnormal post-load (T-post) and combined abnormal blood glucose (T-comb). The percentage of large for gestational age neonates and the mean birth weight centile were greater in the group of women with abnormal fasting blood glucose (T0). The need for insulin treatment was greater in the combined abnormal blood glucose (T-comb). Abnormal fasting blood glucose was the only independent

Conclusion

Women with GDM and abnormal fasting blood glucose are at increased risk for large for gestational age neonates, while women with GDM and combined fasting and post-load abnormal blood glucose are at increased risk for insulin therapy. These women require closer monitoring in order to avoid adverse pregnancy outcomes and further research is needed in order to identify the various pathophysiologic mechanisms that lead to this phenotype.

Declaration of Competing Interest

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Acknowledgements

None.

Funding

The present study received no funding.

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    Both authors contributed equally to this manuscript.

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