In present investigation, relationship between season of birth and season of menopause, and also length of reproductive period were studied. Relationship between age of menopause and ABO & Rh blood groups and total number of pregnancy were studied too. Also, relationship between season of menopause and season of first menarche were investigated. Our population were 129 Hamadanian women.

Results showed that average age of menopause, in our cases was 48.9 years; birth season of 40.3 percent of them was summer, and also, season of menopause in 48.7 percent of them was summer. Frequency of blood group A, was 31.9; and frequency of Rh positive was 80.4 percent, among our subjects. Statistical analysis of obtained data show that there are significant correlations between age and season of menopause and some biological features that we studied.