section name header

Evidence summaries

Abnormal Screening Glucose Challenge Test in Pregnancy and Future Risk of Diabetes

An abnormal screening glucose tolerance test in pregnancy appears to increase the future risk of diabetes. Level of evidence: "B"

Comment: The quality of evidence is upgraded by large magnitude of effect.

In a population-based, retrospective cohort study 1 15 381 women referred for an antepartum oral glucose tolerance test (OGTT) indicative of an abnormal 50-g glucose challenge test (GCT), but without GDM, were matched (for age, region, socioeconomic status, and year of delivery) with up to 4 other women without such referral (n = 61 237). The two cohorts were followed over a median 6.4 years for the development of diabetes. The rate of incident DM was 5.04 cases per 1000 person-years in the cohort of women who underwent an antepartum OGTT, compared with 1.74 cases per 1000 person-years in women without an OGTT. The hazard ratio for subsequent DM in women with abnormal GCT was 2.56 (95% CI 2.28 to 2.87, P < 0.0001).

A cross-sectional study 2 determined the proportion of women who progress to type 2 diabetes mellitus (T2DM) and associated risk factors 5 to 6 years after hyperglycaemia first detected in pregnancy (includes GDM) in Cape Town, South Africa. Each participant had a 75 g OGTT; anthropometric measurements and a survey were administered. Mean age was 37.2 years (SD 6.0). Of the 498 participants 220 were followed-up for 5 - 6 years. 48 % (95% CI 41.2 to 54.4) progressed to T2DM, 5.5% (95% CI 3.1 to 9.4) had impaired fasting glucose, and 10.5% (95% CI 7.0 to 15.3) had impaired glucose tolerance. When GDM was categorized post hoc according to WHO 2013 guidelines, progression in the diabetes in pregnancy group was 81% (95% CI 70.2 to 89.0) and 31.3% (95% CI 24.4 to 39.3) in the GDM category. Factors associated with risk of progression to T2DM were; waist circumference (odds ratios [OR] 1.1, 95% CI 1.0 to 1.1, p = 0.007), hip circumference (OR 0.9, 95% CI 0.8 to 1.0, p = 0.001), and BMI (OR 1.1, 95% CI 1.0 to1.3, p = 0.001), and at baseline: insulin (OR 25.8, 95% CI 3.9 to 171.4, p = 0.001) and oral hypoglycaemic treatment during HFDP (OR 4.1, 95% CI 1.3 to 12.9, p = 0.018), fasting (OR 2.7, 95% CI 1.5 to 4.8, p = 0.001), and oral glucose tolerance test 2-hour glucose concentration at HFDP diagnosis (OR 4.3, 95% CI 2.4 to 7.7, p < 0.001). There was no control group.

References

  • Retnakaran R, Shah BR. Abnormal screening glucose challenge test in pregnancy and future risk of diabetes in young women. Diabet Med 2009;26(5):474-7. [PubMed]
  • Chivese T, Norris SA, Levitt NS. Progression to type 2 diabetes mellitus and associated risk factors after hyperglycemia first detected in pregnancy: A cross-sectional study in Cape Town, South Africa. PLoS Med 2019;16(9):e1002865.[PubMed]

Primary/Secondary Keywords