Aim:
Background: Gestational diabetes mellitus is a common pregnancy condition characterized by the occurrence of spontaneous hyperglycemia throughout pregnancy. Aims: to assess whether various blood groups can be associated with the occurrence of gestational diabetes mellitus and if malondialdehyde can be used for the diagnosis of GDM.

Material and methods:
Methods: A case control study started from September 2022 to June 2023 enrolled 200 pregnant women aged between 15-45 years, cases included 100 patients selectively collected with a confirmed diagnosis of gestational diabetes mellitus, and 100 were healthy normal in Kerbala obstetrics and gynecology hospital, both patient and controls group categorized according to blood group type.

Results:
Results: Pregnant women with gestational diabetes mellitus are mostly of blood group AB in comparison with pregnant women without Gestational diabetes mellitus, and both A and B were significantly higher among control pregnant women, additionally, two groups' blood group O levels were almost identical. Malondialdehyde mean was significantly higher in pregnant women with Gestational diabetes mellitus with p-values 0.001. Statistically significant differences could not be detected in the mean levels of MDA across the various blood groups (p= 0.505).

Conclusions:
Conclusion: This research reveals that mother’s ABO blood group has a role in the development of GDM and the blood group AB is more likely to develop GDM, blood group A & B are less likely to develop GDM and may be regarded as a protective factor. MDA can be used for the diagnosis of GDM but further studies are required to support this finding.