Objectives: This study aimed to evaluate the potential relationship between oxidative stress, dietary intake, and serum levels of antioxidants in patients with a complete hydatidiform mole (CHM) compared with controls.

Methods: This was an observational cross-sectional study conducted in Rio de Janeiro, Brazil. A total of 140 women were enrolled in this study and divided into four groups: 43 patients with CHM, 33 women who had had an abortion, 32 healthy pregnant women, and 32 healthy non-pregnant women. All participants underwent blood sampling, assessment using a semiquantitative food frequency questionnaire, and anthropometric measurement. Blood samples were collected after overnight fasting (10-12 h). Vitamin levels (A, C, and E) were determined by ultra-performance liquid chromatography, and gamma-glutamyl transferase levels were assessed using an automated quantitative analysis system (Dimension®, Siemens).

Results: Although all groups showed sufficient serum vitamin A and E levels, the participants had inadequate dietary intake of these vitamins. Conversely, all groups had an insufficient serum level of vitamin C, despite adequate intake. The gamma-glutamyl transferase values did not differ significantly among the groups. However, elevated serum levels of this enzyme were observed in several patients.

Conclusions: All groups exhibited high levels of oxidative stress, as evaluated by gamma-glutamyl transferase levels, and had inadequate intake of antioxidant vitamins. Therefore, the high exposure to oxidative stress found in our study, even in healthy pregnant and non-pregnant women, may increase the incidence of CHM in this region.