PREDICTORS OF OVARIAN-STEROID SECRETION IN REPRODUCTIVE-AGE WOMEN

During the baseline period (1985-1988) of a prospective study, midcycl e and luteal-phase estrogens and progestins were measured in 175 healt hy women aged 21-36 years with spontaneous, cyclic menses in Brooklyn, New York. Subjects contributed daily first-morning urine specimens an d three blood specimens during a single menstrual cycle monitored by b asal body temperature, Hormone levels were compared according to age, race, and levels of known or suspected breast cancer risk factors, Lat e age at menarche was associated with increased urinary and serum prog estin levels, Increased body weight was associated with decreased prog estin levels, even in ovulatory women. Neither weight nor age at menar che was related to estrogen levels. Cigarette smoking was associated w ith decreased midcycle and luteal-phase estradiol levels, No other fac tors were associated with differences in any of the hormones measured either midcycle or during the luteal phase, despite good statistical p ower to detect moderate differences, Sources of individual variability in ovarian steroid levels remain unexplained, These data do not suppo rt hypotheses that breast cancer risk factors act through an effect on ovarian hormones during the middle reproductive years.