Pregnant women and women taking oral contraceptives show urinary excretion values of 5-S-cysteinyldopa and of 6-hydroxy-5-methoxyindole-2-carboxylic acid in the same range as nonpregnant women not taking oral contraceptives. The excretion of these melanoma markers can therefore be used in in the biochemical diagnosis of metastatic melanoma in pregnancy and in women taking oral contraceptives.