Objective: To evaluate the capacity of vascular endothelial growth factor (VEGF), pregnancy-associated plasma protein-A (PAPP-A), and progesterone (P) to discriminate ectopic pregnancies (EP) from nonectopic ones. Design: Prospective, case-controlled study. Setting: Tertiary care center. Patient(s): Twenty-nine women with EP, 29 women with normal intrauterine pregnancy (nIUP), and 28 women with spontaneous miscarriage, all matched for gestational age. Intervention(s): Serum samples were obtained. Main Outcome Measure(s): Serum concentrations of VEGF, PAPP-A, and P were measured. Result(s): Serum VEGF concentrations did not show statistically significant differences among women with EP (median, 55.24 pg/mL; range, 0.20–179.24), spontaneous miscarriages (median, 26.24 pg/mL; range, 0.22–365.24), and nIUP (median, 43.24 pg/mL; range, 0.86–101.24). The median level of P was significantly increased in the nIUP group (20.58 ng/mL; range, 13.9–37.04) compared with the other two groups, but there was no statistically significant difference between the spontaneous miscarriage and EP groups. Like P, PAPP-A values were also significantly higher in the nIUP group than in the other two groups, but the difference between PAPP-A values in the EP and spontaneous abortion groups was statistically insignificant. Conclusion(s): VEGF, PAPP-A, and P cannot be used to diagnose EPs, but PAPP-A and P can at least be used to differentiate abnormal pregnancies. [Copyright &y& Elsevier]