Objective  To observe the alterations of each menstrual factor in ovarian aging.

  Methods  The data were obtained from one-year observation of a prospective cohort involving 323 healthy women in the age of 30-54 years in a community in Beijing. Menstrual diary was kept and serum level of follicle-stimulating hormone (FSH) was tested. The participants were divided into groups based on age, FSH level, and stages of reproductive aging. Alterations of length of menstrual cycle (LMC), length of menstrual period, and menstrual volume were analyzed in each group.

  Results  Age:the mean LMC extended after the age of 40 years, obviously after 48, and peaked with (67.04±36.77) days in ≥ 52-year-old group. The mean length of menstrual period did not vary much with age. However, the variation of mean length of menstrual period gradually increased with age after 44 years old, peaked in 50- to 51-year-old group. The menstrual volume scores were approximately stable between 38 and 47 years of age, with a peak of(45.06±93.54) in 48- to 49-year-old group and a minimum of (15.87±13.81) in ≥ 52-year-old group. FSH level:LMC increased with elevation of FSH levels. There was no significant difference in the mean length of menstrual period among FSH level groups, but the variation of length of menstrual period was maximum in 20 < FSH ≤ 40 U/L group. The maximum mean menstrual volume score was (30.69±31.84), observed in 10 < FSH ≤ 15 U/L group, while the minimum was (17.38±24.38) in FSH > 40 U/L group. Stages of reproductive aging:the length of menstrual period and menstrual volume scores among each stage showed no statistically significant difference(P > 0.05).

  Conclusions  The LMC altered significantly in ovarian aging, which could be used as staging criteria of reproductive aging. The length of menstrual period and menstrual volume are also showing some characteristic changes, possibly of some clinical values.