Serum concentrations of CA 125, CA 15-3, CA 19-9 and CEA in normal pregnancy: a longitudinal study

Although cancer diagnosed during pregnancy is rare, the coexistence of pregnancy and malignancy becomes more common in view of prolongation of reproductive age. Therefore, it is important that the specificity of a tumor marker be evaluated during pregnancy to avoid misinterpretation in the follow-up of a pregnant cancer patient. The present study aims to investigate the serum concentrations of CA-125, CA 15-3, CA 19-9 and CEA in healthy pregnant women through gestation. In this prospective study, we followed thirty healthy pregnant women. Blood samples were obtained during each trimester of pregnancy (10-12, 22-24 and 34-36 weeks). The maternal serum levels of CA-125, CA 15-3, CA 19-9 and CEA were measured using electrochemiluminescence immunoassay. There was no difference between the first and second trimester serum levels of CA 125, CEA and CA 19-9. However, serum CA 125 levels in third trimester were found to be significantly elevated in pregnants compared to the second trimester (median values 19.6 vs. 15.6 IU/mL, p = 0,009). Similarly, the serum CEA levels in third trimester were significantly higher than those of second trimester (median values 1.1 vs. 0.7 ng/ml, p = 0.001). It is also found that CEA and CA 19-9 assay values were significantly elevated in the third trimester of pregnancy when compared with the first trimester of pregnancy (CEA median values 1.1 vs. 0.7 ng/ml, p = 0.02 and CA 19-9 median values 11.6 vs. 7.7 IU/mL, p = 0,02). Three trimester had statistically similar levels for serum CA 15-3 (median values 17.5, 19.7 and 18.3 U/mL, respectively). The four tumor markers assay values were found generally within the normal range. These findings suggest that maternal serum levels of CA 125, CEA and CA 19-9 were increased during third trimester of pregnancy. However, these elevations were within the normal range. CA 15-3 is independent of gestation and reliable tumor markers in monitoring malignancy in pregnant patients.