Prevalence and Timing of Screening and Diagnostic Testing for Gestational Diabetes Mellitus: A Population-Based Study in Alberta, Canada

Abstract

OBJECTIVEThe extent to which pregnant women are screened for gestational diabetes mellitus (GDM) at the population level is not known. We examined the rate, type, and timing of GDM screening and diagnostic testing in the province of Alberta, Canada. Geographic and temporal differences in screening rates, and maternal risk factors associated with lower likelihood of screening, were also determined. RESEARCH DESIGN AND METHODSOur retrospective linked-database cohort study included 86,842 primiparous women with deliveries between 1 October 2008 and 31 December 2012. Multivariable logistic regression analysis was used to examine maternal factors associated with lower likelihood of GDM screening. RESULTSOverall, 94% (n = 81,304) of women underwent some form of glycemic assessment in the 270 days prior to delivery. The majority (91%) received a 50-g glucose screen (GDS). Women not screened were younger and more likely to smoke and had lower maternal weight and median household income. When a diagnostic 75-g oral glucose tolerance test (OGTT) was indicated, it occurred a median of 10 (interquartile range 7, 15) days after the screen. CONCLUSIONSGDS occurred widely in a system where it was universally recommended and paid for publicly. When indicated, a 75-g OGTT was completed within 15 days in 75% of cases. Our finding that this two-step approach was widely implemented in a timely fashion supports continued endorsement of a two-step approach to screening and diagnosis of GDM. Further research is merited to assess whether the one-step GDM diagnostic approach results in different rates and timing of the 75-g OGTT and affects pregnancy outcomes.The 50-g oral glucose challenge test (GDS) is a common method of screening for gestational diabetes mellitus (GDM) in North America. This test is recommended for all women (1) or selectively for the vast majority (at least 90%) of pregnant women (2) who have at least one risk factor for GDM (i.e., older age, non-Caucasian, elevated BMI, history of adverse pregnancy outcomes, and personal or family history of

Diabetes and Pregnancy

“…Results from a Canadian prospective study show that sequential screening is associated with lower direct and indirect costs while maintaining equivalent diagnostic power when compared with 1-step testing. Recent observational data demonstrated the feasibility and good uptake of the 2-step approach (269).…”

A Modified Two-Step Screening Strategy for Gestational Diabetes Mellitus Based on the 2013 WHO Criteria by Combining the Glucose Challenge Test and Clinical Risk Factors

“…Moreover, randomized controlled trials (RCTs) showing treatment benefits for GDM used a two-step approach with a 50 g glucose challenge test (GCT) or risk factors [ 1 , 2 ]. Several professional associations therefore still adhere to a two-step approach, using a non-fasting GCT to determine whether an OGTT should be performed [ 6 , 9 , 10 ]. The GCT is easier to perform, and it is generally better tolerated than an OGTT [ 11 ].…”

Universal HbA1c Measurement in Early Pregnancy to Detect Type 2 Diabetes Reduces Ethnic Disparities in Antenatal Diabetes Screening: A Population-Based Observational Study

“…Universal HbA1c measurement at booking is also an opportunity to screen vulnerable groups with a low uptake of GDM screening. Despite a universal approach to GDM screening, reported rates of uptake in population-based studies are highly variable ranging from 50.6% to 91% [ 5 – 8 ], with lower screening rates seen in primary care settings and disparities in uptake by ethnicity and age. In NZ, indigenous Māori have a relative high prevalence of type 2 diabetes in children [ 9 ], yet the reported prevalence of GDM in Māori is only 3.3%, less than half the rate found in other non-European groups with similar rates of type 2 diabetes [ 2 ].…”