The relation between plasma testosterone levels and the lengths of phases of the menstrual cycle.

Plasma testosterone levels were measured in 331 women of reproductive age. The incidence of clinical signs of hyperandrogenism (hirsutism, acne) was recorded. Ovulatory activity was evaluated clinically by basal body temperature and frequent observation of changes in the appearance of the cervical os and cervical mucus. Plasma testosterone levels were abnormally elevated in patients with clinical signs of hyperandrogenism. The highest mean testosterone levels were noted in the group of hyperandrogenic women with amenorrhea. Significant prolongation of the follicular phase and shortening of the luteal phase were demonstrated to be associated with clinical signs of hyperandrogenism and elevated plasma testosterone levels. Statistically significant correlations between plasma testosterone levels and duration of phases of the menstrual cycle were observed. Testosterone levels were directly related to the length of the follicular phase and inversely related to the length of the luteal phase. A significant inverse correlation between the lengths of the two phases of the menstrual cycle was also demonstrated. These results suggest an association between hyperandrogenism and prolongation of the follicular phase and shortening of the luteal phase of the menstrual cycle, possibly related to the high incidence of infertility and menstrual irregularity reported for hyperandrogenic women.