Selective versus universal screening for gestational diabetes mellitus: an evaluation of predictive risk factors

Objective: To assess whether selective screening for gestational diabetesmellitus (GDM) on the basis of risk-factor assessment is a practicable alternative to universal screening. Design: Case-control study. Setting: A 212-bed regional specialist hospital in Melbourne, providing services in obstetrics and gynaecology, paediatrics, geriatrics and rehabilitation. Subjects: 6032 women who gave birth at the hospital, May 1996 to August 1997 and November 1997 to August 1998; all were screened for GDM, and 313 were diagnosed with the condition. Main outcome measures: Odds ratios (ORs) for risk factors (age, obesity, family history of diabetes mellitus and high-risk racial heritage) in women with GDM compared to those without GDM; proportion of women with GDM whose diagnosis would have been missed by selective screening. Results: ORs were 1.9 for age greater than or equal to 25 years (95% CI, 1.3-2.7), 2.3 for body mass index greater than or equal to 27 kg/m(2) (95% CI, 1.6-3.3), 2.5 for high-risk racial heritage (95% CI, 2.0-3.2), and 7.1 for family history of diabetes mellitus (95% CI, 5.6-8.9). Other proposed criteria (previous GDM and glycosuria) added no further diagnostic power. Selective screening using the above four criteria would have missed two of 313 cases (0.6%) and could have saved screening up to 1025 women without GDM (17% of all women). Conclusions: Selective screening for GDM based on prior risk assessment can reduce the need for testing, with negligible loss of diagnostic efficiency.