Inadequacy of the risk factor based approach to detect gestational diabetes mellitus.

Objective: To evaluate the present risk factor based approach in diagnosis of gestational diabetes mellitus (GDM) in Sri Lanka in comparison with new guidelines proposed by the International Association of Diabetes and Pregnancy Study Groups (IADPSG).

Methods: A community based cross sectional descriptive study was conducted among pregnant women with gestational age of 24-28 weeks and residing in Anuradhapura district. All eligible pregnant women from selected Medical Officers of Health areas were invited to participate. The 75 g oral glucose tolerance test was carried out among all participants.

Results: According to IADPSG criteria, 36 (8.9%) of pregnant women had GDM, compared to 29 (7.2%) according to WHO criteria. Prevalence of GDM in the study population (positive by one or both methods) was 10.6% (n=43) (95% CI 7.9-13.9%). Of these 43 women,22 (51.1%) had positive results by both methods. Seven (16.3%) and 14 (32.6%) mothers were positive only according to WHO and IADPSG criteria respectively. Out of 29 mothers who fulfilled WHO criteria, only one had an abnormal fasting plasma glucose, but 28 had abnormal 2 hour values. A total of 170 (42.0%) participants had at least one risk factor or early indicator of GDM. A risk based approach would have detected only 22 GDM patients according to IADPSG criteria, missing 14 cases (38.9%) who did not have any of the risk factors for GDM.

Conclusions: The risk factor based approach misses more than one third of GDM cases. Urgent revision of current GDM screening guidelines is recommended.