Background:
Diagnosing gestational diabetes mellitus (GDM) remains controversial, with ongoing disagreement regarding optimal diagnostic criteria to identify and treat women at risk despite the stricter diagnostic criteria recommended by the WHO in 2013. These WHO2013 criteria for GDM (GDMWHO2013) identify pregnancies with milder degrees of hyperglycaemia compared to the current practise in several countries. Fasting glucose levels vary markedly between populations and have been reported high in Danish pregnant women suggesting a high prevalence of GDMWHO2013.
We evaluated maternal and neonatal outcomes in untreated women who met WHO2013 diagnostic criteria for GDM using universal screening.
Methods:
Universal screening for GDM at 24-28 weeks was performed by a 75 g oral glucose tolerance test with assessment of venous plasma glucose at 0, 1-hour and 2-hours in a prospective unselected cohort. GDM diagnosis was defined by current Danish “2-hour glucose ³9.0mmol/L only” criterion (GDMDK) and by WHO2013 criteria (fasting ³5.1, 1-hour ³10.0 or 2-hour glucose ³8.5 mmol/L, GDMWHO2013). Presence of GDMDK, GDMWHO2013 and New-GDM (GDMWHO2013 positive and GDMDK negative) was reported.
Results:
Universal GDM screening was completed by 465 pregnant women at 25.7 weeks, of whom 62% fulfilled the Danish indications for risk-factor-based screening. GDMWHO2013 prevalence was 21.5% (N=100) and GDMDK 2.2% (N=10). New-GDM was seen in 19.4% (N=90/465), of whom 90% (N=81) had a fasting glucose ³5.1 mmol/L and these women were left untreated. New-GDM-women had higher frequencies of pregnancy-induced hypertension (13.3 vs 4.1%, P=0.002) and caesarean section (28.9 vs 18.7%, P=0.042) than No-GDM-women. Neonates of the New-GDM-women had higher birth weight z-scores (0.43 vs -0.11, P<0.0001) and frequencies of large-for-gestational-age (22.2 vs 9.9%, P=0.004), neonatal hypoglycaemia (8.9 vs 1.9%, P=0.004) and admission to intensive care unit (16.7 vs 5.8%, P=0.002).
Conclusion:
GDM prevalence increased 10-fold to one out of five when applying the WHO2013 diagnostic criteria in a Danish population. The untreated women diagnosed by WHO2013 criteria and their offspring had clinically relevant higher risks of adverse outcomes than women without GDM and would probably have benefitted from lifestyle advice.