Oral glucose tolerance testing outcomes among women at high risk for gestational diabetes mellitus.

Aims: This study aimed to determine the prevalence and relationships with known risk factors of gestational diabetes mellitus (GDM) at University College Hospital, Ibadan, Nigeria.

Methods: Records of all women referred for oral glucose tolerance testing at the metabolic research unit of the Hospital over a 2 year period were reviewed. Diagnosis of GDM was made in accordance with WHO criteria. GDM diagnosis was classified as early and late based on a gestational age <24 weeks and >24 weeks respectively. Body mass index (BMI) measurements were performed for women who presented in the first trimester. Various statistical tools including student t test and Pearson's coefficient of correlation were used.

Results: A total of 765 records were reviewed. The crude prevalence rate was 13.9%. The prevalence rate among women in the first trimester was highest at 17.4% although most of the diagnoses were made in the third trimester (55.7%). A positive family history and a family history of GDM were associated significantly with a higher fasting and 2 h post-load glucose values, irrespective of current GDM diagnosis. The most consistent associations with a diagnosis of GDM were a positive family history and a history of GDM. Age above 30 years at oral glucose testing also showed significant association. There was no BMI threshold associated with a significant risk of GDM for those women presenting in the first trimester.

Conclusions: GDM is a common metabolic condition in Nigeria. Onset before the 24th week of pregnancy is not uncommon.