Introduction: alterations in the circulating level of tumour necrosis factor-α (TNF-α) has been proposed to be involved in the pathogenesis of gestational diabetes mellitus (GDM), but its role is not completely understood, findings from studies done across different ethnic groups are often inconsistent. We carried out this study to determine maternal serum level of TNF-a and it's association with body weight status in a group of Nigerian women with GDM.

Methods: a cross sectional analytical study conducted among 169 pregnant women, 85 with GDM and 84 with normal gestation. Diagnosis of GDM was made between 24-28 weeks gestation according to the WHO diagnostic criteria. Maternal serum level of TNF-α was measured and compared between the study groups.

Results: maternal serum TNF-α level was significantly higher in the pregnant women with GDM than in the controls (2.50 ± 0.30 vs. 2.10 ± 0.30 pg/ml, p < 0.05). Also when comparing the serum TNF-α levels of the pregnant women with GDM and the controls for each level of body mass index, serum TNF-α levels remained significantly higher in both the normal weight and overweight pregnant women with GDM compared to their matched controls (2.40 ± 0.30 vs. 1.90 ± 0.20 pg/ml, p < 0.05) and (2.60 ± 0.30 vs. 2.30 ± 0.20 pg/ml, p < 0.05) respectively.

Conclusion: it is concluded that pregnant women with GDM in this study have higher maternal serum TNF-α level compared to the pregnant women with normal glucose tolerance regardless of body weight status.