Background: The oral glucose tolerance test (OGTT) is the gold standard for diagnosing Gestational Diabetes (GDM). A diagnosis of GDM increases detrimental interventions, without evidence for improved outcomes unless diabetes is overt, or macrosomia extreme. Sensible diagnosis of GDM is paramount, given the test is undertaken by a majority of pregnant women. This study assesses whether a standard 75g glucose load for women of all statures presents an unfair metabolic burden to shorter women and makes a positive OGTT more likely.
Method: This is a retrospective cohort analysis performed at a single centre in Perth, Western Australia. All women who delivered at this centre in 2019 were considered for the study (n=2557); women were excluded if they did not have an OGTT or had a pre-pregnancy diagnosis of diabetes. Results from the OGTT were analysed against maternal height and controlled for body mass index.
Results: There is a positive relationship between maternal height and one and two-hour blood glucose levels, and this trend persists across all BMI categories.
Discussion: These results suggest that there is a relationship between maternal height and blood glucose levels in response to the 75g glucose load of the OGTT, supporting the hypothesis that the OGTT poses an unfair metabolic burden to shorter women.
Implications for practice: The OGTT discriminates unfairly; consideration should be given to altering the glucose dose or diagnostic parameters to produce a fairer test that does not disadvantage shorter women.