Variation of luteinizing hormone and androgens in oligomenorrhoea and its implications for the study of polycystic ovary syndrome

We measured luteinizing hormone (LH) and androgen concentrations in patient s at different phases of the oligomenorrhoeic cycle and compared the result s with those of patients with nonnogonadotrophic amenorrhoea, Several blood samples separated by greater than or equal to 7 days were obtained from ea ch of 72 patients with oligomenorrhoea and 18 with normogonadotrophic ameno rrhoea. The oligomenorrhoeic cycle was divided into five phases: the postme nstrual phase week 1 (day 1-7) and week 2 (day 8-14), the specific oligomen orrhoeic phase (SOP, day 15 after a menstruation to day 21 before the next menstruation), the possibly periovulatory phase (days 21-11 before menstrua tion) and the premenstrual phase (days 10-1 before menstruation). Samples o btained in the possibly peri-ovulatory phase were excluded. Within individu als LN concentrations were significantly higher during the SOP than during all other phases of the oligomenorrhoeic cycle (paired a-test, P = 0.0001-0 .03). In contrast to the other phases of the oligomenorrhoeic cycle, no sig nificant differences in gonadotrophins, androgen or oestradiol concentratio ns were found between the SOP and normogonadotrophic amenorrhoea, In oligom enorrhoea timing of blood sampling influences the measurement of LH and and rogen concentrations, and the accurate interpretation of these measurements requires that the dates of menstruation both before and after the sample i s taken should be known. In patients with oligomenorrhoea blood samples sho uld be obtained during the SOP, when the endocrinology is comparable with t hat of normogonadotrophic amenorrhoea.