This study aims to assess the relationship between oxidative DNA damage and
iron status in women with
gestational diabetes mellitus (GDM) compared to those with normal
glucose tolerance in the first and the second trimesters of pregnancy. Maternal serum and urine samples were collected in the 11th-14th weeks and the 24th-28th weeks of gestation. In addition to oral
glucose tolerance test in the second trimester, fasting
blood glucose, HbA1c,
ferritin and
hemoglobin levels were measured in blood samples. Urinary levels of oxidative DNA damage products
8-hydroxy-2'-deoxyguanosine (8-OH-dG) and 8,5'-cyclo-2'-deoxyadenosines (S-cdA, R-cdA) were determined using liquid chromatography-tandem mass spectrometry with
isotope-dilution. In the first trimester, urinary
8-OH-dG levels were found higher in the GDM group (n = 33) than in the control group (n = 84) (p = 0.006). R-cdA and S-cdA levels were not significantly different between the two groups (p = 0.794 and p = 0.792 respectively). When the cases were stratified according to their first trimester
ferritin levels, women with ≥50th centile (≥130 ng/mL) demonstrated higher levels of
8-OH-dG and R-cdA than those under <50th centile (p = 0.034, p = 0.009). In the GDM group, there was a positive correlation between the second trimester
8-OH-dG and
ferritin and 1st-hour
glucose levels (p = 0.014, p = 0.020). This is the first study where oxidative DNA damage is evaluated in both early and late periods of pregnancy. Our findings reveal an association between GDM and
iron status and oxidative DNA damage.