The prevalence of gestational diabetes mellitus amongst black South African women is a public health concern

Abstract

Aims: This study aimed to determine the prevalence of gestational diabetes mellitus (GDM) amongst black South African women, describe GDM-associated risk factors and clinical management, and evaluate the efficacy of the fasting plasma glucose reading in diagnosing GDM.

Methods: A cross-sectional screening study was performed. Pregnant women were recruited from the Chris Hani Baragwanath Academic Hospital in Johannesburg. A total of 1906 women underwent a two-hour 75 g oral glucose tolerance test at 24-28 weeks gestation. The World Health Organization's 2013 criteria were used to diagnose GDM.

Results: A total of 174/1906 (9.1% (95% confidence interval (CI) 7.9, 10.5)) women were diagnosed with GDM. These women had significantly higher weights and body mass indexes (BMIs), were significantly older, of higher household socioeconomic status, more likely to report a family history of diabetes, and more likely to be diagnosed with anaemia than women without GDM. An age of ≥35 years, BMI ≥ 30 kg/m², and a family history of diabetes were significant risk factors. The fasting plasma glucose reading had a high sensitivity (83.3% (95% CI 77.0, 88.5)) in diagnosing GDM and 56.9% of the women with GDM were managed by diet therapy alone.

Conclusion: This is the largest GDM prevalence study in South Africa to date. A diagnosis of GDM increases the risk of both mother and child developing Type 2 diabetes which causes further health complications, decreases longevity, and burdens a country's healthcare system. Therefore, a GDM prevalence of 9.1% is concerning and warrants further discussion around current GDM screening policies.

Keywords: Epidemiology; Gestational diabetes mellitus; Pregnancy; Screening.