Menstrual cycle characteristics and steroid hormone, prolactin, and growth factor levels in premenopausal women.

PurposeMenstrual cycle characteristics are markers of endocrine milieu. However, associations between age at menarche and adulthood sex steroid hormone levels have been inconsistent, and data on menstrual characteristics and non-sex steroid hormones are sparse.MethodsWe assessed the relations of menstrual characteristics with premenopausal plasma sex steroid hormones, sex hormone binding globulin (SHBG), prolactin, and growth factors among 2,745 premenopausal women (age 32-52) from the Nurses' Health Study II. Geometric means and tests for trend were calculated using multivariable general linear models.ResultsEarly age at menarche was associated with higher premenopausal early-follicular free estradiol (percent difference  13 years = 11%), early-follicular estrone (7%), luteal estrone (7%), and free testosterone (8%) (all p trend < 0.05). Short menstrual cycle length at age 18-22 was associated with higher early-follicular total ( 39 days = 18%) and free estradiol (16%), early-follicular estrone (9%), SHBG (7%), lower luteal free estradiol (- 14%), total (- 6%), and free testosterone (- 15%) (all p trend < 0.05). Short adult menstrual length was associated with higher early-follicular total estradiol ( 31 days = 14%), SHBG (10%), lower luteal estrone (- 8%), progesterone (- 9%), total (- 11%) and free testosterone (- 25%), and androstenedione (- 14%) (all p trend < 0.05). Irregularity of menses at 18-22 was associated with lower early-follicular total (irregular vs. very regular = - 14%) and free estradiol (- 14%), and early-follicular estrone (- 8%) (All p trend < 0.05). Irregularity of adult menstrual cycle was associated with lower luteal total estradiol (irregular vs. very regular = - 8%), SHBG (- 3%), higher total (8%), and free testosterone (11%) (all p trend < 0.05).ConclusionsEarly-life and adulthood menstrual characteristics are moderately associated with mid-to-late reproductive year's hormone concentrations. These relations of menstrual characteristics with endogenous hormone levels could partially account for associations between menstrual characteristics and reproductive cancers or other chronic diseases.