The hormonal profile in a patient with an ectopic pregnancy (EP) differs in many respects from that of a patient with a normal intrauterine pregnancy (IUP). Although there are several reports using different hormones for early diagnosis of ectopic pregnancy most of the results are contradictory. In this study, therefore, we prospectively investigated the maternal serum level of beta-human chorionic gonadotropin (beta-hCG), progesterone (P), estradiol (E2), human placental lactogen (HPL), alfafetoprotein (AFP) and cancer antigen 125 (CA 125) during the first trimester of normal and abnormal pregnancies. Serum samples were obtained from 20 women with normal IUPs, 15 women whose pregnancies complicated with spontaneous abortion and 31 women with surgically and pathologically confirmed EPs. The mean serum levels of beta-hCG, E2 and p in patients with EPs (9490.55 +/- 3071.2 mlU/ml, 100.1 +/- 22.09 pg/ml, 4.18 +/- 1.19 ng/ml, respectively) were significantly lower than those measured in normal IUPs (73796.8 +/- 15554.7 mlU/ml, 500.15 +/- 98.84 pg/ml, 19.2 +/- 2.8 ng/ml, respectively p < 0.001) and significantly lower than in patients with spontaneous abortion (22524 +/- 6213 mlU/ml, p < 0.05, 339.8 +/- 112.16 pg/ml, p < 0.01, 10.59 +/- 3.03 ng/ml, p < 0.05 respectively). No significant difference was recorded with respect to serum levels of HPL, AFP and CA 125 among the groups. We also investigated the diagnostic value of simple E2 and P in patients with EPs. We could not identify a discriminatory cutoff value because there was a considerable overlap in serum P and E2 levels between the patients with IUPs and EPs.(ABSTRACT TRUNCATED AT 250 WORDS)