To Örebro University

BACKGROUND: The Swedish National Board of Health and Welfare (SNBHW) recommended the new diagnostic criteria for GDM based upon Hyperglycaemia and Adverse Pregnancy Outcomes (HAPO) study thresholds. Due to limited knowledge base, no recommendations were made on GDM screening. The aim of this study is to evaluate test characteristics of risk factors and fasting blood glucose as screening tests for diagnosing GDM using diagnostic thresholds based upon HAPO study 1.75/2.0 (model I/II respectively) odds ratio for adverse pregnancy outcomes.

METHODS: This cross-sectional, population-based study included all pregnant women who attended maternal health care in Örebro County, Sweden between the years 1994-96. A 75 g OGTT with capillary fasting and 2-h blood glucose was offered to all pregnant women at week 28-32. Risk factors and repeated random glucose samples were collected. Sensitivity, specificity and predictive values of blood glucose were calculated.

RESULTS: Prevalence of GDM was 11.7% with model I and 7.2% with the model II criteria. Risk factors showed 28%, (95% CI 24-32) and 31%, (95% CI 25-37) sensitivity for model I and II respectively. A fasting cut off ≥4.8 mmol/l occurred in 24% of women with 91%, (95% CI 88-94) sensitivity and 85%, (95% CI 83-86) specificity using model I while a fasting cut off ≥5.0 mmol/l occurred in 14% with 91%, (95% CI 87-94) sensitivity and 92%, (95% CI 91-93) specificity using model II.

CONCLUSION: Risk factor screening for GDM was found to be poorly predictive of GDM but fasting glucose of 4.8-5.0 mmol/l showed good test characteristics irrespective of diagnostic model and results in a low rate of OGTTs.

AIMS: Quantify the proportional increase in gestational diabetes (GDM) prevalence when implementing the new International Association of Diabetes and Pregnancy Study Groups (IADPSG) criteria compared to prior GDM criteria, and to assess risk factors that might affect the change in prevalence.

METHODS: A systematic review and meta-analysis was performed of cohort and cross-sectional studies between January 1, 2010 to December 31, 2018 among pregnant women with GDM using IADPSG criteria compared to, and stratified by, old GDM criteria. Web of science, PubMed, EMBASE, Cochrane, Open Grey and Grey literature reports were included. The relative risk for each study was calculated. Subgroup analyses were performed by maternal age, body mass index, study design, country of publication, screening method, sampling method and data stratified according to diagnostic criteria.

RESULTS: Thirty-one cohort and cross-sectional studies with 136 705 women were included. Implementing the IADPSG criteria was associated with a 75% (RR 1.75, 95% CI 1.53-2.01) increase in number of women with GDM with evidence of heterogeneity CONCLUSIONS: The IADPSG criteria increase the prevalence of GDM, but allow movement towards more homogeneity. More studies are needed of the benefits, harms, psychological effects and health costs of implementing the IADPSG criteria.