Copper/Zinc Ratio Can Be a Marker to Diagnose Ectopic Pregnancy and Is Associated with the Oxidative Stress Status of Ectopic Pregnancy Cases

It was aimed to evaluate serum zinc and copper levels and oxidative stress parameters in ectopic pregnancy cases, healthy pregnant women, and healthy non-pregnant women. In this cross-sectional case-control study, 30 patients diagnosed with tubal ectopic pregnancy in the gynecology clinic of a tertiary hospital constituted the study group. A healthy pregnant control group (n = 30) was formed of age, body mass index (BMI), and gestational week-matched subjects, and a healthy non-pregnant control group (n = 30) was formed of age and BMI-matched women. The groups were compared in terms of demographic characteristics and laboratory parameters including serum zinc (Zn) level, serum copper (Cu) level, serum malondialdehyde (MDA) level, serum catalase (CAT) activity, serum glutathione peroxidase (GPX) activity, and serum superoxide dismutase (SOD) activity. The groups were similar in respect of demographic characteristics. In the ectopic pregnancy group, serum GPX activity and Cu level were significantly lower, and serum SOD and CAT activity and Zn and MDA levels were higher compared with those of the healthy pregnant and healthy non-pregnant groups. The Cu/Zn ratio showed a significant, positive correlation with the serum GPX activity and serum progesterone level and a negative correlation with serum SOD and CAT activity. When 1.14 was taken as the cutoff value, sensitivity and specificity of the Cu/Zn ratio to determine ectopic pregnancy were 73.3% and 80.0%, respectively. Comparing the area under curve (AUC) in the ROC (receiver operating characteristic) curve analysis, the Cu/Zn ratio was determined to be more valuable than the Cu or Zn values alone in predicting ectopic pregnancy. In correlation analysis, serum beta hCG level showed a negative correlation with SOD and CAT activities and Zn levels. Serum progesterone level showed a negative correlation with serum CAT and SOD activities and MDA and zinc levels and a positive correlation with serum GPX activity and serum copper level (p < 0.05 for all). The current study can be considered of value as the first study in literature to show a significantly lower serum Zn level and higher serum Cu level in ectopic pregnancy cases compared with healthy pregnant control cases. This is also the first study to have revealed an association between the serum Cu/Zn ratio, oxidative status, and ectopic pregnancy. Furthermore, the serum Cu/Zn ratio was found to be useful in the diagnosis of ectopic pregnancy cases.