Abnormal glucose challenge test in absence of oral glucose tolerance test – are there consequences?

Abstract

This is a retrospective analysis of mothers with abnormal 1-hour, 50-grams glucose challenge test (GCT) who did not take a 3-hour, 100-gram oral glucose tolerance test (OGTT). This study group of women was compared to three control groups, based on an OGTT diagnostic test- normal OGTT, single pathological value and gestational diabetes mellitus. Overall- 4,185 women were included and sub-divided accordingly into four groups: Group A-340 (8.12%)- no OGTT; Group B-2,585 (61.77%)- Norm OGTT (All values normal); Group C- 564 (13.48%)- SinOGTT (single pathological value) and Group D- 696 (16.63%)- Gestational Diabetes Mellitus (GDM, ≥ 2 pathological values). Groups A, C and D had higher rates of intrapartum Caesarean Delivery (10.29%, 11.52% and 10.19% vs. 8.43%, p < .0001). Group A had highest rates of neonatal adverse outcomes, as neonatal intensive care unit (NICU) admission (12.4% vs. 8.4%, 11.0% and 10.0%, p = .039), small for gestational age (SGA) neonates (7.0% vs. 5.3%, 3.7% and 6.0%, p = .0092) and neonatal hypoglycaemia (3.5% vs. 1.3%, 3.2% and 2.9%, p = .007). A multivariable regression revealed that having an abnormal GCT without an OGTT was an independent risk factor for neonatal intensive care unit admission, neonatal hypoglycaemia and intrapartum caesarean delivery. We concluded that women with pathological GCT who did not complete OGTT have higher rates of obstetric adverse outcomes. They should be closely monitored during delivery and should not be overlooked. IMPACT STATEMENT What is already known on this subject? Adverse outcomes of gestational diabetes mellitus are well established. But, the group of women who fail to complete a confirmatory OGTT following a pathological GCT is not well described. What the results of this study add? Our results point out that women who fail to complete an OGTT, suffer from higher rates of obstetric complications, presumably attributed to disrupted glucose values, but also to poor prenatal care. What the implications are of these findings for clinical practice and/or further research? These women should not be overlooked. They should be closely monitored during labour and delivery.