In 2015, Queensland Health changed its screening and diagnostic criteria for GDM, in line with the ADIPS Consensus Guidelines. This resulted in 37% more women being diagnosed with GDM. To date, there have been mixed results on the impact of changing the diagnostic criteria for GDM. This study aimed to examine the impact of changing diagnostic criteria on perinatal outcomes for women diagnosed with GDM in Queensland.
Methods
We used routinely collected Queensland perinatal data of over 124,000 women to examine the difference in perinatal outcomes in the year before (2014) and after (2016) state-wide policy was changed for diagnosing GDM. Logistic regression was used to estimate the odds ratio (OR) and 95% confidence intervals (CIs) for the risk of developing key perinatal outcomes in women with GDM.
Results
In 2016, 11.9% (n = 7317) of pregnant women were diagnosed with GDM compared with 8.7% (n = 5462) in 2014. There was no difference detected for the following outcomes: pregnancy-induced hypertension (OR 1.20, 95% CI 0.88 – 1.18), caesarean delivery (OR 0.94, 95% CI 0.86 - 1.02); small-for-gestational age infants (OR 0.90 95% CI 0.79 – 1.03) and large-for-gestational age infants (OR 0.91, 95% CI 0.81 - 1.00). There was a reduction in preterm birth (OR 0.87, 95% CI 0.78 - 0.97), and respiratory distress (OR 0.83, 95% CI 0.73 - 0.95), but an increase in neonatal hypoglycaemia (OR 1.21, 95% CI 1.10 - 1.34).
Discussion
Our results add to the growing body of evidence that changing diagnostic criteria has had little impact on many outcomes for women GDM. Our study represents the largest sample of Australia women examined to date. Considering the increased costs associated with treating GDM and the personal and emotional burden a GDM diagnosis has on women, the changed diagnostic criteria needs to be questioned.