Hyperprolactinemia is a disease when it contributes to cycle disorders. It concerns women with extremely extended or shortened cycle – if it is extended, we have to exclude PCOS. In case of a patient without polycystic ovary syndrome but with low AMH and long cycles, we can suspect that the reason is abnormal prolactin level. However, in the majority of cases we evaluate, women have normal cycles, i.e. ovulatory cycles, but still they are treated for hyperprolactinemia – according to the abnormal result, while the patient is healthy. Prolactin is a problem inasmuch as its basic level is hard to examine. There are many factors which influence its rise, e.g. drinking a cup of coffee. Before the test, in order to obtain a reliable result, the patient should be calm, relaxed and free from stress.