Potential Impact of Revising the Diagnostic Criteria for Gestational Diabetes on Maternal Pregnancy and Infant Perinatal Outcomes.

AIMS: The revised diagnostic criteria for gestational diabetes (GDM) in New Zealand include lowering the fasting glucose from the current ≥ 5.5 to ≥ 5.3 mmol/L and replacing the current 2-h post-load glucose (≥ 9.0 mmol/L) with a 1-h glucose (≥ 10.6 mmol/L). We assessed the effects of these changes on the demographics of those diagnosed and their perinatal outcomes.

MATERIALS AND

METHODS

Participants in the GEMS trial were grouped as meeting only the revised criteria (Additional group), only the current criteria (Missed group), both criteria (Both-Criteria group), and neither criteria (Non-GDM group).

RESULTS

GDM prevalence among 3921 participants was 6.8% using the revised criteria and 5.8% using the current criteria (risk ratio 1.18, 95% CI 1.00-1.40). Women in the Additional (n = 125) and Missed groups (n = 83), who would be affected by the changes, were more likely to be overweight/obese, have a family history of diabetes, and have Asian ethnicity than women in the Non-GDM group (n = 3562). They also had less gestational weight gain and more induced labors, while their infants were born earlier, had lower birthweight, and more neonatal hypoglycemia (all p < 0.001). Women in the Missed group had lower BMI and fewer were of Pacific ethnicity than the Both-Criteria group (n = 151). They also had less pharmacotherapy use and postpartum hemorrhage.

CONCLUSIONS

Using the revised criteria will increase GDM diagnoses by identifying a high-risk group of women likely to benefit from treatment, but 35.5% of women currently treated for GDM will no longer be diagnosed, potentially compromising their health.